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Document and Entity Information - USD ($)	12 Months Ended
Document and Entity Information - USD ($)	Dec. 31, 2019	Mar. 05, 2020	Jun. 30, 2019
Document and Entity Information
Document Type	10-K
Document Period End Date	Dec. 31, 2019
Entity Registrant Name	BICYCLE THERAPEUTICS PLC
Entity Well Known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Interactive Data Current	Yes
Entity Small Business	true
Entity Emerging Growth Company	true
Entity Ex Transition Period	true
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		17,994,772
Entity Public Float			$ 114,461,603
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0001761612
Amendment Flag	false

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash	$ 92,117	$ 63,380
Accounts receivable	201	5,021
Prepaid expenses and other current assets	4,884	2,076
Research and development incentives receivable	6,944	6,292
Total current assets	104,146	76,769
Property and equipment, net	2,292	1,818
Operating lease right‑of‑use assets	2,056
Other assets	1,700	3,039
Total assets	110,194	81,626
Current liabilities:
Accounts payable	1,949	1,887
Accrued expenses and other current liabilities	6,144	7,032
Deferred revenue, current portion	728	10
Total current liabilities	8,821	8,929
Warrant liability		4,804
Operating lease liabilities	1,251
Deferred revenue, net of current portion	4,929	14,625
Other long‑term liabilities	1,995	897
Total liabilities	16,996	29,255
Commitments and contingencies (Note 12)
Shareholders’ equity (deficit):
Ordinary shares, £0.01 nominal value; 31,995,653 and 15,452,420 shares authorized at December 31, 2019 and December 31, 2018, respectively; 17,993,701 shares issued and outstanding at December 31, 2019; 898,675 shares issued and 814,728 shares outstanding at December 31, 2018	227	10
Additional paid‑in capital	195,056	1,857
Accumulated other comprehensive loss	(1,535)	(1,751)
Accumulated deficit	(100,550)	(69,942)
Total shareholders’ equity (deficit)	93,198	(69,826)
Total liabilities, convertible preferred shares and shareholders’ equity (deficit)	$ 110,194	81,626
Series A Convertible Preferred Shares
Shareholders’ equity (deficit):
Convertible preferred shares		41,820
Series B1 Convertible Preferred Shares
Shareholders’ equity (deficit):
Convertible preferred shares		54,621
Series B2 Convertible Preferred Shares
Shareholders’ equity (deficit):
Convertible preferred shares		$ 25,756

Consolidated Balance Sheets (Parenthetical) - £ / shares	Dec. 31, 2019	Dec. 31, 2018
Ordinary shares, nominal value	£ 0.01	£ 0.01
Ordinary shares, shares authorized	31,995,653	15,452,420
Ordinary shares, shares issued	17,993,701	898,675
Ordinary shares, shares outstanding	17,993,701	814,728
Series A Convertible Preferred Shares
Convertible preferred shares, nominal value	£ 0.01	£ 0.01
Convertible preferred shares, shares authorized	0	3,000,001
Convertible preferred shares, shares issued	0	2,800,001
Convertible preferred shares, shares outstanding	0	2,800,001
Series B1 Convertible Preferred Shares
Convertible preferred shares, nominal value	£ 0.01	£ 0.01
Convertible preferred shares, shares authorized	0	4,690,485
Convertible preferred shares, shares issued	0	3,947,198
Convertible preferred shares, shares outstanding	0	3,947,198
Series B2 Convertible Preferred Shares
Convertible preferred shares, nominal value	£ 0.01	£ 0.01
Convertible preferred shares, shares authorized	0	1,403,633
Convertible preferred shares, shares issued	0	1,323,248
Convertible preferred shares, shares outstanding	0	1,323,248

Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Operations and Comprehensive Loss
Collaboration revenues	$ 13,801	$ 7,136	$ 2,060
Operating expenses:
Research and development	25,540	20,761	11,866
General and administrative	14,560	8,121	6,407
Total operating expenses	40,100	28,882	18,273
Loss from operations	(26,299)	(21,746)	(16,213)
Other income (expense):
Interest and other income	814	169	50
Other expense, net	(5,377)	(665)	(119)
Total other expense, net	(4,563)	(496)	(69)
Net loss before income tax provision	(30,862)	(22,242)	(16,282)
Benefit from income taxes	(254)	(396)	(23)
Net loss	(30,608)	(21,846)	(16,259)
Net loss attributable to ordinary shareholders	$ (30,608)	$ (21,846)	$ (16,259)
Net loss per share attributable to ordinary shareholders, basic and diluted	$ (2.77)	$ (49.78)	$ (48.81)
Weighted average ordinary shares outstanding, basic and diluted	11,045,370	438,862	333,125
Comprehensives Loss:
Net loss	$ (30,608)	$ (21,846)	$ (16,259)
Other comprehensive income (loss):
Foreign currency translation adjustment	216	(1,820)	2,355
Total comprehensive loss	$ (30,392)	$ (23,666)	$ (13,904)

Consolidated Statements of Convertible Preferred Shares and Shareholders’ Equity (Deficit) - USD ($) $ in Thousands	Series A Convertible Preferred Shares	Series B1 Convertible Preferred Shares	Series B2 Convertible Preferred Shares	Ordinary Shares	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit	Total
Beginning balance at Dec. 31, 2016	$ 41,820
Beginning balance (in shares) at Dec. 31, 2016	2,800,001
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares		$ 54,621
Issuance of convertible preferred shares (in shares)		3,947,198
Ending balance at Dec. 31, 2017	$ 41,820	$ 54,621
Ending balance (in shares) at Dec. 31, 2017	2,800,001	3,947,198
Beginning balance at Dec. 31, 2016				$ 4	$ 323	$ (2,286)	$ (31,837)	$ (33,796)
Beginning balance (in shares) at Dec. 31, 2016				316,215
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards				$ 1	114			115
Issuance of restricted share awards (in shares)				48,480
Issuance of ordinary shares upon exercise of share options (in shares)				4,300
Share based compensation expense					401			401
Foreign currency translation adjustment						2,355		2,355
Net loss							(16,259)	(16,259)
Ending balance at Dec. 31, 2017				$ 5	838	69	(48,096)	(47,184)
Ending balance (in shares) at Dec. 31, 2017				368,995
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares			$ 25,756
Issuance of convertible preferred shares (in shares)			1,323,248
Ending balance at Dec. 31, 2018	$ 41,820	$ 54,621	$ 25,756
Ending balance (in shares) at Dec. 31, 2018	2,800,001	3,947,198	1,323,248
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards				$ 1	223			224
Issuance of restricted share awards (in shares)				95,644
Issuance of ordinary shares in exchange for surrender of vested share options				$ 4	(4)
Issuance of ordinary shares in exchange for surrender of vested share options (in shares)				340,728
Issuance of ordinary shares upon exercise of share options (in shares)				9,361
Share based compensation expense					800			800
Foreign currency translation adjustment						(1,820)		(1,820)
Net loss							(21,846)	(21,846)
Ending balance at Dec. 31, 2018				$ 10	1,857	(1,751)	(69,942)	$ (69,826)
Ending balance (in shares) at Dec. 31, 2018				814,728				814,728
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares			$ 1,583
Issuance of convertible preferred shares (in shares)			80,385
Conversion of convertible preferred shares to ordinary shares	$ (41,820)	$ (54,621)	$ (27,339)
Conversion of convertible preferred shares to ordinary shares (in shares)	(2,800,001)	(3,947,198)	(1,403,633)
Ending balance (in shares) at Dec. 31, 2019	0	0	0
Increase (decrease) in shareholders' equity (deficit)
Conversion of convertible preferred shares to ordinary shares				$ 146	123,634			$ 123,780
Conversion of convertible preferred shares to ordinary shares (in shares)				11,647,529
Reclassification of warrant liability to additional paid-in capital and exercise of warrants				$ 9	10,018			10,027
Reclassification of warrant liability to additional paid-in capital and exercise of warrants (in shares)				723,992
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses of $8.5 million				$ 59	56,322			56,381
Number of shares issued (in shares)				4,637,666
Issuance of restricted share awards				$ 2	395			397
Issuance of restricted share awards (in shares)				83,947
Issuance of ordinary shares upon exercise of share options				$ 1	142			143
Issuance of ordinary shares upon exercise of share options (in shares)				85,839
Share based compensation expense					2,688			2,688
Foreign currency translation adjustment						216		216
Net loss							(30,608)	(30,608)
Ending balance at Dec. 31, 2019				$ 227	$ 195,056	$ (1,535)	$ (100,550)	$ 93,198
Ending balance (in shares) at Dec. 31, 2019				17,993,701				17,993,701

Consolidated Statements of Convertible Preferred Shares and Shareholders’ Equity (Deficit) (Parenthetical) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Consolidated Statements of Convertible Preferred Shares and Shareholders’ Equity (Deficit)
Offering expenses	$ 587
Fair value of warrants	$ 3,254

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net loss	$ (30,608)	$ (21,846)	$ (16,259)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	3,083	1,023	515
Depreciation and amortization	960	712	332
Change in fair value of warrant liability	5,381	665	119
Changes in operating assets and liabilities:
Accounts receivable	4,909	(400)
Non-cash research and development expense			856
Research and development incentives receivable	(383)	(3,586)	(1,407)
Prepaid expenses and other current assets	(2,723)	(1,329)	(330)
Operating lease right‑of‑use assets	712
Other assets	(397)	(301)	(1,039)
Accounts payable	220	(169)	67
Accrued expenses and other current liabilities	(852)	2,557	1,267
Lease liabilities	(709)
Deferred revenue	(9,295)	(3,947)	14,081
Other long-term liabilities	1,089	543	383
Net cash used in operating activities	(28,613)	(26,078)	(1,415)
Cash used in investing activities:
Purchases of property and equipment	(1,555)	(1,186)	(1,113)
Net cash used in investing activities	(1,555)	(1,186)	(1,113)
Cash flows from financing activities:
Proceeds from issuance of ADSs in initial public offering, net of issuance costs	56,957	(576)
Proceeds from the exercise of share options and sale of ordinary shares	143	1	1
Proceeds from the exercise of warrants	6
Net cash provided by financing activities	58,440	25,430	57,876
Effect of exchange rate changes on cash	465	(2,449)	2,913
Net increase (decrease) in cash	28,737	(4,283)	58,261
Cash at beginning of period	63,380	67,663	9,402
Cash at end of period	92,117	63,380	67,663
Supplemental disclosure of cash flow information
Cash paid for income taxes	117	73
Cash paid for amounts included in the measurement of operating lease liabilities	891
Purchases of property and equipment included in accounts payable and accrued expenses	76
Advance billings on deferred revenue included in accounts receivable		5,045
Deferred initial public offering costs accrued but not paid		1,076
Conversion of convertible preferred shares to ordinary shares upon closing of the initial public offering	123,780
Reclassification of warrant liability to additional paid-in capital	10,021
Series B1 Convertible Preferred Shares
Cash flows from financing activities:
Proceeds from issuance of convertible preferred shares, net of issuance costs			$ 57,875
Series B2 Convertible Preferred Shares
Cash flows from financing activities:
Proceeds from issuance of convertible preferred shares, net of issuance costs	$ 1,334	26,005
Supplemental disclosure of cash flow information
Series B2 convertible preferred financing costs accrued but not paid		$ 249

Nature of the business and basis of presentation	12 Months Ended
Nature of the business and basis of presentation	Dec. 31, 2019
Nature of business and basis of presentation
Nature of the business and basis of presentation	1. Nature of the business and basis of presentation Bicycle Therapeutics plc (collectively with its subsidiaries, the “Company”) is a clinical‑stage biopharmaceutical company developing a novel and differentiated class of medicines, which the Company refers to as Bicycles, for diseases that are underserved by existing therapeutics. Bicycles are a unique therapeutic modality combining the pharmacology usually associated with a biologic with the manufacturing and pharmacokinetic properties of a small molecule. The Company’s initial internal programs are focused on oncology indications with high unmet medical need. The Company’s lead product candidate, BT1718, is a Bicycle Toxin Conjugate (“BTC”) that is being developed to target tumors that express Membrane Type 1 matrix metalloprotease. BT1718 is being investigated for safety, tolerability and efficacy in an ongoing Phase I/IIa clinical trial in collaboration with, and fully funded by, the Centre for Drug Development of Cancer Research UK. The Company is also evaluating BT5528, a second-generation BTC targeting Ephrin type‑A receptor 2, or EphA2, in a Company-sponsored Phase I/II study and conducting Investigational New Drug application, or IND, ‑enabling activities for BT8009, a BTC targeting Nectin-4. The Company’s discovery pipeline in oncology includes Bicycle-based systemic immune cell agonists and Bicycle tumor-targeted immune cell agonists (TICAs™). Beyond oncology, the Company is collaborating with biopharmaceutical companies and organizations in therapeutic areas that include anti‑infective, cardiovascular, ophthalmology and respiratory indications. The accompanying consolidated financial statements include the accounts of Bicycle Therapeutics plc and its wholly owned subsidiaries, BicycleTx Limited, BicycleRD Limited and Bicycle Therapeutics Inc. All intercompany balances and transactions have been eliminated on consolidation. The accompanying consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Share capital reorganization In May 2019, the Company’s board of directors and shareholders approved the reorganization of the Company’s share capital by issuing ordinary shares as bonus shares to each holder of ordinary shares on the basis of 1.429 bonus shares for each ordinary share in issue (having the effect of a one for 1.429 share split (without having an impact on the nominal value of the ordinary shares)), which was effected on May 13, 2019. All issued and outstanding share and per share amounts of ordinary shares and share options included in the accompanying consolidated financial statements have been adjusted to reflect this share split for all periods presented. In addition, the number of ordinary shares that will be issued to the holders of the Company’s convertible preferred shares (Note 6) and warrants to subscribe for Series A and Series B1 convertible preferred shares (Note 7) in conjunction with the closing of the initial public offering (“IPO”) has been adjusted accordingly, as well as the number of ordinary shares over which options have been granted. On May 22, 2019, Bicycle Therapeutics Limited (“BTL”) re-registered as a public limited company, and changed its name to Bicycle Therapeutics plc. The Company historically conducted its business through BTL and its wholly owned subsidiaries, BicycleTx Limited, BicycleRD Limited and Bicycle Therapeutics Inc., and, therefore the historical consolidated financial statements previously presented the consolidated results of operations of BTL. Following the completion of the Company’s re-registration in May 2019, the consolidated financial statements of BTL became the historical consolidated financial statements of the Company. Initial public offering On May 28, 2019, the Company completed its IPO, pursuant to which it issued and sold 4,333,333 American Depositary Shares (“ADSs”), representing the same number of ordinary shares at a public offering price of $14.00 per ADS. In addition, in June 2019, the Company issued and sold an additional 304,333 ADSs, pursuant to the partial exercise of the underwriters’ option to purchase additional ADSs. The aggregate net proceeds received by the Company from the IPO were $56.4 million, after deducting underwriting discounts and commissions of $4.5 million and offering expenses of $4.0 million. Upon the closing of the IPO, all of the Company’s outstanding convertible preferred shares automatically converted into 11,647,529 ordinary shares, on a 1:1.429 basis. In addition, warrants to subscribe for Series A and Series B1 convertible preferred shares that were not exercised in conjunction with the IPO automatically became warrants to subscribe for ordinary shares, and meet the criteria to be classified as shareholders’ equity (deficit). As such, following the final remeasurement on May 28, 2019, the Company reclassified the carrying value of the warrant liability to additional paid-in-capital in the consolidated balance sheet. 2017 Reorganization Prior to December 2017, the development of Bicycles was conducted by Bicycle Therapeutics Limited (for the purpose of the 2017 Reorganization referred to as “BTL OldCo.”), a limited liability company incorporated in England and Wales on July 13, 2009, and its wholly‑owned U.S. subsidiary, Bicycle Therapeutics Inc., which was incorporated in Delaware in April 2016. During 2017, the Company entered into a series of transactions to effect a reorganization, and created a new holding company to facilitate its ability to pursue an IPO, Bicycle Therapeutics Limited (for the purpose of the 2017 Reorganization referred to as “BTL NewCo.”). These transactions are collectively referred to as the 2017 Reorganization. The 2017 Reorganization was enacted through a share‑for‑share exchange pursuant to which the shareholders of BTL OldCo. exchanged their shares for equivalent shares of BTL NewCo. Thereafter, BTL OldCo. transferred the entire issued share capital in Bicycle Therapeutics Inc. to BTL NewCo. and certain of its assets, including all employees, were transferred to BicycleTx Limited, a newly created subsidiary of BTL NewCo. The 2017 Reorganization was accounted for as a transaction of entities under common control. Upon completion of the 2017 Reorganization, the historical consolidated financial statements of BTL OldCo. became the historical consolidated financial statements of the Company, which had nominal assets and liabilities and had not conducted any operations other than the actions incidental to the share exchange and its incorporation. The Company concluded that the reorganization resulted in no change in the material rights and preferences of each respective class of equity interests and no change in the fair value of each respective class of equity interests before and after the reorganization. Liquidity The Company is subject to risks common to companies in the biotechnology industry, including but not limited to, risks of failure of preclinical studies and clinical trials, the need to obtain marketing approval for any drug product candidate that it may identify and develop, the need to successfully commercialize and gain market acceptance of its product candidates, dependence on key personnel and collaboration partners, protection of proprietary technology, compliance with government regulations, development by competitors of technological innovations, and the ability to secure additional capital to fund operations. Product candidates currently under development will require significant additional research and development efforts, including preclinical and clinical testing and regulatory approval prior to commercialization. Even if the Company’s research and development efforts are successful, it is uncertain when, if ever, the Company will realize significant revenue from product sales. The accompanying consolidated financial statements have been prepared on the basis of continuity of operations, realization of assets and the satisfaction of liabilities and commitments in the ordinary course of business. Since inception, the Company has devoted substantially all of its efforts to business planning, research and development, recruiting management and technical staff, and raising capital. The Company has funded its operations with proceeds from sales of convertible preferred shares (Note 6) and proceeds received from its collaboration arrangements (Note 10) and most recently, with proceeds from the IPO completed in May 2019. The Company has incurred recurring losses since inception, including net losses of $30.6 million for the year ended December 31, 2019, $21.8 million for the year ended December 31, 2018 and $16.3 million for the year ended December 31, 2017. As of December 31, 2019, the Company had an accumulated deficit of $100.6 million. The Company expects to continue to generate operating losses in the foreseeable future. As of March 10, 2020, the issuance date of the annual consolidated financial statements for the year ended December 31, 2019, the Company expects that its cash will be sufficient to fund its operating expenses and capital expenditure requirements through at least twelve months from the issuance date of the annual consolidated financial statements. The Company expects its expenses to increase substantially in connection with ongoing activities, particularly as the Company advances its preclinical activities and clinical trials for its product candidates in development. Accordingly, the Company will need to obtain additional funding in connection with continuing operations. If the Company is unable to raise capital when needed, or on attractive terms, it could be forced to delay, reduce or eliminate its research or drug development programs or any future commercialization efforts. Although management continues to pursue these plans, there is no assurance that the Company will be successful in obtaining sufficient funding on terms acceptable to the Company to fund continuing operations, if at all.

Summary of Significant Accounting Policies

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies

Summary of Significant Accounting Policies

2. Summary of Significant Accounting Policies

Use of estimates

The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, the disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of expenses during the reporting periods. Significant estimates and assumptions reflected in these consolidated financial statements include, but are not limited to, the accrual for research and development expenses, revenue recognition, the fair value of ordinary shares and the valuation of the warrant liability prior to the Company’s IPO, share-based compensation expense, and income taxes. The Company bases its estimates on historical experience, known trends and other market‑specific or other relevant factors that it believes to be reasonable under the circumstances. Estimates are periodically reviewed in light of reasonable changes in circumstances, facts and experience. Changes in estimates are recorded in the period in which they become known. Actual results could differ from those estimates or assumptions.

Foreign currency and currency translation

The functional currency is the currency of the primary economic environment in which an entity’s operations are conducted. On June 1, 2019, Bicycle Therapeutics plc adopted the U.S. dollar as its functional currency. Bicycle Therapeutics plc is a holding company that has no operating activities and its primary functions are to serve as a financing vehicle to fund the operations of the Company’s operating entities, to serve as the listing company needed to access U.S. capital markets, and to hold investments. Therefore, its financing source is the primary indicator of its cash flows and its functional currency. The change in functional currency from the British Pound Sterling is due to a change in the source of Bicycle Therapeutics plc’s financing and cash flows, which following the completion of the IPO is now primarily the U.S. Dollar (“USD”). Historically its financing had been in British Pound Sterling.

The functional currency of Bicycle Therapeutics plc’s wholly owned non-U.S. subsidiaries, BicycleTx Limited and BicycleRD Limited, is the British Pound Sterling and the functional currency of its U.S. subsidiary, Bicycle Therapeutics Inc. is the USD. The functional currency of the Company’s subsidiaries is the same as the local currency.

Monetary assets and liabilities denominated in currencies other than the functional currency are remeasured into the functional currency at rates of exchange prevailing at the balance sheet dates. Non‑monetary assets and liabilities denominated in foreign currencies are remeasured into the functional currency at the exchange rates prevailing at the date of the transaction. Exchange gains or losses arising from foreign currency transactions are included in the determination of net loss for the respective periods. Adjustments that arise from exchange rate changes on transactions denominated in a currency other than the local currency are included in general and administrative expense in the consolidated statements of operations and comprehensive loss as incurred. The Company recorded a foreign exchange gain of $0.9 million, a foreign exchange gain of $0.3 million and a foreign exchange loss of $0.6 million and for the years ended December 31, 2019, 2018 and 2017, respectively.

The Company translates the assets and liabilities of BicycleTx Limited and BicycleRD Limited into USD at the exchange rate in effect on the balance sheet date. Revenues and expenses are translated at the average exchange rate in effect during the period. Unrealized translation gains and losses are recorded as a cumulative translation adjustment, which is included in the consolidated statements of convertible preferred shares and shareholders’ equity (deficit) as a component of accumulated other comprehensive loss.

Concentrations of credit risk and of significant suppliers

Financial instruments that potentially expose the Company to concentrations of credit risk consist primarily of cash and accounts receivable. The Company deposits its cash in financial institutions in amounts that may exceed federally insured limits and has not experienced any losses on such accounts. The Company does not believe it is exposed to any unusual credit risk beyond the normal credit risk associated with commercial banking relationships.

Accounts receivable primarily consist of amounts due under the collaboration agreements between BicycleTx Limited and AstraZeneca AB (“AstraZeneca”) and Sanofi (formerly Bioverativ) and between BicycleRD Limited and Oxurion NV. (“Oxurion”), formerly ThromboGenics NV. (Note 10), for which the Company does not obtain collateral. As of December 31, 2019, the Company’s revenue to date has primarily been generated from the collaboration agreements with AstraZeneca, Sanofi, the Dementia Discovery Fund and Oxurion.

The Company relies, and expects to continue to rely, on a small number of vendors to manufacture supplies and raw materials for its development programs. These programs could be adversely affected by a significant interruption in these manufacturing services or the availability of raw materials.

Cash and cash equivalents

The Company considers all highly liquid investments with original maturities of three months or less at date of purchase to be cash equivalents. The Company had no cash equivalents at December 31, 2019 and 2018.

Accounts receivable

The Company makes judgments as to its ability to collect outstanding receivables and provides an allowance for receivables when collection becomes doubtful. Provisions are made based upon a specific review of all significant outstanding invoices and the overall quality and age of those invoices. To date, the Company has not had any write‑offs of bad debt, and the Company did not have an allowance for doubtful accounts as of December 31, 2019 and 2018.

Deferred offering costs

The Company capitalizes certain legal, professional accounting and other third‑party fees that are directly associated with in‑process equity financings as deferred offering costs until such financings are consummated. After consummation of the equity financing, these costs are recorded in shareholders’ equity (deficit) as a reduction of proceeds generated as a result of the offering. Should an in‑process equity financing be abandoned, the deferred offering costs will be expensed immediately as a charge to operating expenses in the consolidated statements of operations and comprehensive loss.

Property and equipment

Property and equipment are stated at cost, less accumulated depreciation and amortization. Depreciation and amortization expense is recognized using the straight‑line method over the estimated useful lives of the respective assets as follows:


		Estimated Useful Life
Laboratory equipment		3 to 5 years
Leasehold improvements		Lesser of lease term or useful life
Computer equipment		3 years
Furniture and office equipment		5 years

Costs for capital assets not yet placed into service are capitalized as construction‑in‑progress and depreciated in accordance with the above guidelines once placed into service. Upon retirement or sale, the cost of assets disposed of and the related accumulated depreciation are removed from the accounts and any resulting gain or loss is included in loss from operations. As of December 31, 2019 and 2018, there have been no significant asset retirements to date. Expenditures for repairs and maintenance are charged to expense as incurred.

Impairment of long‑lived assets

Long‑lived assets consist of property and equipment. Long‑lived assets to be held and used are tested for recoverability whenever events or changes in business circumstances indicate that the carrying amount of the assets may not be fully recoverable. Factors that the Company considers in deciding when to perform an impairment review include significant underperformance of the business in relation to expectations, significant negative industry or economic trends and significant changes or planned changes in the use of the assets. If an impairment review is performed to evaluate a long‑lived asset group for recoverability, the Company compares forecasts of undiscounted cash flows expected to result from the use and eventual disposition of the long‑lived asset group to its carrying value. An impairment loss would be recognized when estimated undiscounted future cash flows expected to result from the use of an asset group are less than its carrying amount. The impairment loss would be based on the excess of the carrying value of the impaired asset group over its fair value, determined based on discounted cash flows. To date, the Company has not recorded any impairment losses on long‑lived assets.

Fair value measurements

Certain assets and liabilities of the Company are carried at fair value under GAAP. Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. Valuation techniques used to measure fair value must maximize the use of observable inputs and minimize the use of unobservable inputs. Financial assets and liabilities carried at fair value are to be classified and disclosed in one of the following three levels of the fair value hierarchy, of which the first two are considered observable and the last is considered unobservable:

Level 1 — Quoted prices in active markets for identical assets or liabilities.

Level 2 — Observable inputs (other than Level 1 quoted prices), such as quoted prices in active markets for similar assets or liabilities, quoted prices in markets that are not active for identical or similar assets or liabilities, or other inputs that are observable or can be corroborated by observable market data.

Level 3 — Unobservable inputs that are supported by little or no market activity that are significant to determining the fair value of the assets or liabilities, including pricing models, discounted cash flow methodologies and similar techniques.

Prior to the IPO, the Company’s warrant liability was carried at fair value, determined according to the fair value hierarchy described above (Note 3). The carrying values of accounts receivable, research and development incentives receivable, other current assets, accounts payable and accrued expenses and other current liabilities approximate their fair values due to the short‑term nature of these assets and liabilities.

Warrant liability

Prior to the IPO, the Company classified warrants to subscribe for Series A and Series B1 convertible preferred shares (Note 6) as a liability on its consolidated balance sheets as these warrants to subscribe for Series A and Series B1 convertible preferred shares were free‑standing financial instruments that might have required the Company to transfer assets upon exercise. The warrant liability was initially recorded at fair value upon the date of the warrants’ issuance and was subsequently remeasured to fair value at each reporting date. Changes in the fair value of the warrant liability were recognized as a component of other expense, net in the consolidated statements of operations and comprehensive loss. Upon the closing of the IPO, warrants to subscribe for Series A and Series B1 convertible preferred shares that were not exercised or expired in conjunction with the IPO automatically became warrants to subscribe for ordinary shares, and meet the criteria to be classified as shareholders’ equity (deficit). As such, following the final remeasurement on May 28, 2019, the Company reclassified the carrying value of the warrant liability to additional paid-in-capital in the consolidated balance sheet.

Segment and geographic information

Operating segments are defined as components of a business for which separate discrete financial information is available for evaluation by the chief operating decision maker in deciding how to allocate resources and assess performance. The Company and its chief operating decision maker, the Company’s Chief Executive Officer, view the Company’s operations and manages its business as a single operating segment, which is developing a unique class of chemically synthesized medicines based on its proprietary constrained peptides.

The Company operates in two geographic regions: the United Kingdom and the United States.

Leases

The Company determines if an arrangement is a lease at inception. Operating leases are included in operating lease right‑of‑use (“ROU”) assets, other current liabilities, and operating lease liabilities in the Company’s consolidated balance sheet. The Company has not entered into any financing leases.

ROU assets represent the Company’s right to use and control an underlying asset for the lease term and lease liabilities represent the Company’s obligation to make lease payments arising from the lease. ROU assets and liabilities are recognized at commencement date based on the present value of lease payments over the lease term. As the Company’s leases do not provide an implicit rate, the Company uses its incremental borrowing rate based on the information available at commencement date in determining the present value of lease payments. The ROU asset also includes lease payments made before the lease commencement date and excludes any lease incentives. The Company’s lease terms may include options to extend or terminate the lease when it is reasonably certain that the Company will exercise that option.

The components of a lease shall be split into three categories, if applicable: lease components (e.g., land, building, etc.), non‑lease components (e.g., common area maintenance, maintenance, consumables, etc.), and non‑components (e.g., property taxes, insurance, etc.). The fixed and in‑substance fixed contract consideration (including any related to non‑components) must then be allocated based on fair values to the lease components and non‑lease components. The Company’s facilities operating leases may have lease and non‑lease components to which the Company has elected to apply a practical expedient to account for each lease component and related non‑lease component as one single component. The lease component results in a right‑of‑use asset being recorded on the balance sheet. Lease expense for lease payments is recognized on a straight‑line basis over the lease term.

Revenue recognition

The Company’s revenues are generated primarily through collaborative arrangements and license agreements with pharmaceutical companies. The terms of these arrangements may include (i) performing research and development services using the Company’s bicyclic peptide screening platform with the goal of identifying compounds for further development and commercialization, (ii) options to obtain additional research and development services or licenses for additional targets, or to optimize product candidates, upon the payment of option fees, or (iii) the transfer of intellectual property rights (licenses).

The terms of these arrangements typically include payment to the Company of one or more of the following: non‑refundable, upfront license fees; payments for research and development services; fees upon the exercise of options to obtain additional services or licenses; payments based upon the achievement of defined collaboration objectives; future regulatory and sales‑based milestone payments; and royalties on net sales of future products.

The Company recognizes revenue in accordance with ASU 2014‑09, Revenue from Contracts with Customers (Topic 606) (“ASC 606”) and all subsequent amendments. This standard applies to all contracts with customers, except for contracts that are within the scope of other standards, such as leases, insurance, collaboration arrangements and financial instruments.

Under ASC 606, an entity recognizes revenue when its customer obtains control of promised goods or services, in an amount that reflects the consideration which the entity expects to receive in exchange for those goods or services.

To determine revenue recognition for arrangements that the Company determines are within the scope of ASC 606, it performs the following five steps: (i) identify the contract(s) with a customer; (ii) identify the performance obligations in the contract; (iii) determine the transaction price; (iv) allocate the transaction price to the performance obligations in the contract; and (v) recognize revenue when, or as, the Company satisfies the performance obligations. The Company only applies the five‑step model to contracts when it is probable that the entity will collect substantially all of the consideration it is entitled to in exchange for the goods or services it transfers to the customer. As part of the accounting for these arrangements, the Company must make significant judgments, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each performance obligation.

Once a contract is determined to be within the scope of ASC 606, the Company assesses the goods or services promised within the contract and determines those that are performance obligations. Arrangements that include rights to additional goods or services that are exercisable at a customer’s discretion are generally considered options. The Company assesses if these options provide a material right to the customer and if so, they are considered performance obligations.

Performance obligations are promised goods or services in a contract to transfer a distinct good or service to the customer. The promised goods or services in the Company’s contracts with customers primarily consist of license rights to the Company’s intellectual property for research and development, research and development services, options to acquire additional research and development services, and options to obtain additional licenses, such as a commercialization license for a potential product candidate. Promised goods or services are considered distinct when: (i) the customer can benefit from the good or service on its own or together with other readily available resources, and (ii) the promised good or service is separately identifiable from other promises in the contract. In assessing whether promised goods or services are distinct, the Company considers factors such as the stage of development of the underlying intellectual property, the capabilities of the customer to develop the intellectual property on their own and whether the required expertise is readily available. In addition, the Company considers whether the collaboration partner can benefit from a promise for its intended purpose without the receipt of the remaining promises, whether the value of the promise is dependent on the unsatisfied promises, whether there are other vendors that could provide the remaining promises, and whether it is separately identifiable from the remaining promises.

The Company estimates the transaction price based on the amount of consideration the Company expects to receive for transferring the promised goods or services in the contract. The consideration may include both fixed consideration and variable consideration. At the inception of each arrangement that includes variable consideration, the Company evaluates the amount of the potential payments and the likelihood that the payments will be received. The Company utilizes either the most likely amount method or expected value method to estimate variable consideration to include in the transaction price based on which method better predicts the amount of consideration expected to be received. The amount included in the transaction price is constrained to the amount for which it is probable that a significant reversal of cumulative revenue recognized will not occur. At the end of each subsequent reporting period, the Company re‑evaluates the estimated variable consideration included in the transaction price and any related constraint, and if necessary, adjusts its estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch‑up basis in the period of adjustment.

After the transaction price is determined it is allocated to the identified performance obligations based on the estimated standalone selling price. The Company must develop assumptions that require judgment to determine the standalone selling price for each performance obligation identified in the contract. The Company utilizes key assumptions to determine the standalone selling price, which may include other comparable transactions, pricing considered in negotiating the transaction, probabilities of technical and regulatory success and the estimated costs. Certain variable consideration is allocated specifically to one or more performance obligations in a contract when the terms of the variable consideration relate to the satisfaction of the performance obligation and the resulting amounts allocated to each performance obligation are consistent with the amounts the Company would expect to receive for each performance obligation.

The Company then recognizes as revenue in the amount of the transaction price that is allocated to the respective performance obligation when (or as) each performance obligation is satisfied at a point in time or over time, and if over time based on the use of an input method.

Licenses of intellectual property: If a license to the Company’s intellectual property is determined to be distinct from the other promises or performance obligations identified in the arrangement, the Company recognizes revenue from non‑refundable, upfront fees allocated to the license when the license is transferred to the customer and the customer is able to use and benefit from the license. For licenses that are combined with other promises, such as research and development services and a research license, the Company utilizes judgment to assess the nature of the combined performance obligation to determine whether the combined performance obligation is satisfied over time or at a point in time and, if over time, the appropriate method of measuring progress for purposes of recognizing revenue. The Company evaluates the measure of progress each reporting period and, if necessary, adjusts the measure of performance and related revenue recognition. The measure of progress, and thereby periods over which revenue should be recognized, are subject to estimates by management and may change over the course of the research and development and licensing agreement.

Research and Development Services: The promises under the Company’s collaboration agreements may include research and development services to be performed by the Company on behalf of the partner. Payments or reimbursements resulting from the Company’s research and development efforts are recognized as the services are performed and presented on a gross basis because the Company is the principal for such efforts.

Customer Options: The Company evaluates the customer options to obtain additional items (i.e. additional license rights) for material rights, or options to acquire additional goods or services for free or at a discount. Optional future services that reflect their standalone selling prices do not provide the customer with a material right and, therefore, are not considered performance obligations and are accounted for as separate contracts. If optional future services include a material right, they are accounted for as performance obligations. The Company determines an estimated standalone selling price of any material rights for the purpose of allocating the transaction price. The Company considers factors such as the identified discount and the probability that the customer will exercise the option. Amounts allocated to a material right are not recognized as revenue until, at the earliest, the option is exercised or expires.

Milestone payments: The Company’s collaboration agreements may include development and regulatory milestones. The Company evaluates whether the milestones are considered probable of being reached and estimates the amount to be included in the transaction price using the most likely amount method. The Company evaluates factors such as the scientific, clinical, regulatory, commercial, and other risks that must be overcome to achieve the particular milestone in making this assessment. If it is probable that a significant revenue reversal would not occur, the associated milestone value is included in the transaction price. Milestone payments that are not within the Company’s control or the licensee’s control, such as regulatory approvals, are not considered probable of being achieved until those approvals are received. At the end of each reporting period, the Company re‑evaluates the probability of achievement of such milestones and any related constraint, and if necessary, adjusts the estimate of the overall transaction price. Any such adjustments are recorded on a cumulative catch‑up basis, which would affect collaboration revenue and net loss in the period of adjustment.

Royalties: For sales‑based royalties, including milestone payments based on the level of sales, the Company determines whether the sole or predominant item to which the royalties relate is a license. When the license is the sole or predominant item to which the sales‑based royalty relates, the Company recognizes revenue at the later of: (i) when the related sales occur, or (ii) when the performance obligation to which some or all of the royalty has been allocated has been satisfied (or partially satisfied). To date, the Company has not recognized any sales‑based royalty revenue resulting from the Company’s collaboration agreements.

The Company receives payments from customers based on billing schedules established in each contract. Up‑front payments and fees are recorded as deferred revenue upon receipt or when due until the Company performs its obligations under these arrangements. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional, such as when the Company has a contractual right to payment per the terms of the contract.

For a complete discussion of accounting for collaboration revenues, see Note 10, “Significant Agreements”

Government grants

From time to time, the Company may enter into arrangements with governmental entities for the purposes of obtaining funding for research and development activities. The Company recognizes government grant funding in the consolidated statements of operations and comprehensive loss as the related expenses being funded are incurred. The Company classifies government grants received under these arrangements as a reduction to the related research and development expense incurred. The Company analyzes each arrangement on a case‑by‑case basis. For the year ended December 31, 2019, the Company recognized $0.6 million, as a reduction of research and development expense related to government grant arrangements. There were no grant proceeds recognized for the years ended December 31, 2018 or 2017.

Research and development costs

Research and development costs are expensed as incurred. Research and development expenses consist of costs incurred in performing research and development activities, including salaries, share‑based compensation and benefits, travel, facilities costs, materials and laboratory supplies, and external costs of outside vendors engaged to conduct preclinical development, clinical development activities, as well as to manufacture clinical trial materials. Facilities costs primarily include the allocation of rent, utilities, and depreciation.

Non‑refundable prepayments for goods or services that will be used or rendered for future research and development activities are deferred and capitalized until the related goods are delivered or the related services are performed, or until it is no longer expected that the goods will be delivered, or the services rendered.

Research and manufacturing contract costs and accruals

The Company has entered into various research and development and manufacturing contracts, including contracts with respect to preclinical studies and clinical trials, with companies both inside and outside of the United States. These agreements are generally cancelable with 90 days or less notice, and related costs are recorded as research and development expenses as incurred. The Company records accruals for estimated ongoing costs. When evaluating the adequacy of the accrued liabilities, the Company analyzes progress of the research and development and manufacturing activities, including the phase or completion of events, invoices received and contracted costs. Significant judgments and estimates are made in determining the accrued balances at the end of any reporting period. Actual results could differ from the Company’s estimates. The Company’s historical accrual estimates have not been materially different from the actual costs.

Research and development incentives and receivable

The Company, through its subsidiaries in the United Kingdom, receives reimbursements of certain research and development expenditures as part of a United Kingdom government’s research and development tax reliefs program. Under the program, the Company is able to surrender trading losses that arise from qualifying research and development expenses incurred by the Company’s subsidiaries in the United Kingdom for a tax credit of up to 14.5% of the surrenderable losses.

Management has assessed the Company’s research and development activities and expenditures to determine which activities and expenditures are likely to be eligible under the research and development incentive program described above. At each period end, management estimates the reimbursement available to the Company based on available information at the time.

The Company recognizes income from the research and development incentives when the relevant expenditure has been incurred, the associated conditions have been satisfied and there is reasonable assurance that the reimbursement will be received. The Company records these research and development incentives as a reduction to research and development expenses in the statements of operations and comprehensive loss, as the research and development tax credits are not dependent on us generating future taxable income, the Company’s ongoing tax status, or tax position. The research and development incentives receivable represent an amount due in connection with the above program. The Company recorded a reduction to research and development expense of $6.7 million, $5.9 million and $2.9 million during the years ended December 31, 2019, 2018 and 2017, respectively.

Patent costs

All patent‑related costs incurred in connection with preparing, filing and prosecuting patent applications are expensed as incurred due to the uncertainty about the recovery of the expenditure. Amounts incurred are classified as general and administrative expenses in the consolidated statements of operations and comprehensive loss.

Share‑based compensation

The Company measures all equity awards granted to employees and directors based on the fair value on the date of grant. Compensation expense of those awards is recognized over the requisite service period, which is generally the vesting period of the respective award. The Company records the expense for awards with only service‑based vesting conditions using the straight‑line method. The Company accounts for forfeitures as they occur.

The Company has granted awards with both a service condition that vest over time and a performance condition that will accelerate vesting upon the achievement of a specified collaboration revenue threshold. For equity awards that contain both performance and service conditions, the Company recognizes share‑based compensation expense using an accelerated attribution model over the requisite service period when the achievement of a performance‑based milestone is probable based on the relative satisfaction of the performance condition as of the reporting date.

For share‑based awards granted to non‑employee consultants, the measurement date for non-employee awards is the date of grant. The compensation expense is then recognized over the requisite service period, which is the vesting period of the respective award, without subsequent changes in the fair value of the award.

The fair value of each restricted ordinary share award is based on the fair value of the Company’s ordinary shares, less any applicable purchase price. The fair value of each share option is estimated using the Black‑Scholes option‑pricing model, which requires inputs based on certain subjective assumptions, including the fair value of ordinary shares, the expected share price volatility, the expected term of the award, the risk‑free interest rate, and expected dividends.

Prior to the IPO, the Company utilized significant estimates and assumptions in determining the fair value of its common stock. Given the absence of an active market for the Company’s ordinary shares, the board of directors determined the estimated fair value of the Company’s equity instruments based on input from management which utilized the most recently available independent third‑party valuation, and considering a number of objective and subjective factors, including external market conditions affecting the biotechnology industry sector. The third party valuation reports performed utilized various valuation methodologies in accordance with the framework of the American Institute of Certified Public Accountants’ Technical Practice Aid, Valuation of Privately‑Held Company Equity Securities Issued as Compensation, to estimate the fair value of its ordinary shares. Each valuation methodology includes estimates and assumptions that require judgment. These estimates and assumptions include a number of objective and subjective factors in determining the value of the Company’s ordinary shares at each grant date, including the following: (1) prices paid for the Company’s convertible preferred shares, which the Company had sold to outside investors in arm’s‑length transactions, and the rights, preferences, and privileges of the Company’s convertible preferred shares and ordinary shares; (2) the Company’s stage of development; (3) the fact that the grants of share‑based awards involved illiquid securities in a private company; and (4) the likelihood of achieving a liquidity event for the ordinary shares underlying the share‑based awards, such as an IPO or sale of the Company, given prevailing market conditions.

Expected volatility is calculated based on reported volatility data for a representative group of publicly traded companies for which historical information was available. The historical volatility is calculated based on a period of time commensurate with the assumption used for the expected term. The risk‑free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant commensurate with the expected term assumption. The Company uses the simplified method, under which the expected term is presumed to be the midpoint between the vesting date and the end of the contractual term. The Company utilizes this method due to the lack of historical exercise data and the plain nature of its share‑based awards. The Company uses the remaining contractual term for the expected life of non‑employee awards. The expected dividend yield is assumed to be zero as the Company has never paid dividends and has no current plans to pay any dividends on ordinary shares.

The Company classifies share‑based compensation expense in its consolidated statements of operations and comprehensive loss in the same manner in which the award recipient’s payroll costs are classified or in which the award recipient’s service payments are classified.

Comprehensive loss

Comprehensive loss includes net loss as well as other changes in shareholders’ equity (deficit) that result from transactions and economic events other than those with shareholders. The Company records unrealized gains and losses related to foreign currency translation as a component of other comprehensive loss in the consolidated statements of operations and comprehensive loss.

Contingencies

Liabilities for loss contingencies arising from claims, assessments, litigation, fines, penalties and other sources are recorded when it is probable that a liability has been incurred and the amount can be reasonably estimated. At each reporting date, the Company evaluates whether or not a potential loss amount or a potential loss range is probable and reasonably estimable under the provisions of the authoritative guidelines that address accounting for contingencies. The Company expenses costs as incurred in relation to such legal proceedings as general and administrative expense within the consolidated statements of operations and comprehensive loss.

Income taxes

The Company accounts for income taxes using the asset and liability method, which requires the recognition of deferred tax assets and liabilities for the expected future tax consequences of events that have been recognized in the consolidated financial statements or in the Company’s tax returns. Deferred tax assets and liabilities are determined on the basis of the differences between the consolidated financial statements and tax basis of assets and liabilities using enacted tax rates in effect for the year in which the differences are expected to reverse. Changes in deferred tax assets and liabilities are recorded in the provision for income taxes. The Company assesses the likelihood that its deferred tax assets will be recovered from future taxable income and, to the extent it believes, based upon the weight of available evidence, that it is more likely than not that all or a portion of the deferred tax assets will not be realized, a valuation allowance is established through a charge to income tax expense. Potential for recovery of deferred tax assets is evaluated by estimating the future taxable profits expected and considering prudent and feasible tax planning strategies.

The Company accounts for uncertainty in income taxes recognized in the consolidated financial statements by applying a two‑step process to determine the amount of tax benefit to be recognized. First, the tax position must be evaluated to determine the likelihood that it will be sustained upon external examination by the taxing authorities. If the tax position is deemed more‑likely‑than‑not to be sustained, the tax position is then assessed to determine the amount of benefit to recognize in the consolidated financial statements. The amount of the benefit that may be recognized is the largest amount that will more likely than not be realized upon ultimate settlement. The provision for income taxes includes the effects of any resulting tax reserves, or unrecognized tax benefits, that are considered appropriate as well as the related net interest and penalties.

Net loss per share

The Company follows the two‑class method when computing net loss per share as the Company has issued shares that meet the definition of participating securities. The two‑class method determines net loss per share for each class of ordinary and preferred securities according to dividends declared or accumulated and participation rights in undistributed earnings. The two‑class method requires income available to ordinary shareholders for the period to be allocated between ordinary and preferred securities based upon their respective rights to receive dividends as if all income for the period had been distributed.

Basic net loss per share attributable to ordinary shareholders is computed by dividing the net loss attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding for the period. Diluted net loss attributable to ordinary shareholders is computed by adjusting net loss attributable to ordinary shareholders to reallocate undistributed earnings based on the potential impact of dilutive securities. Diluted net loss per share attributable to ordinary shareholders is computed by dividing the diluted net loss attributable to ordinary shareholders by the weighted average number of ordinary shares outstanding for the period, including potential dilutive ordinary shares assuming the dilutive effect of ordinary share equivalents.

Prior to the Company’s IPO, convertible preferred shares contractually entitled the holders of such shares to participate in dividends but contractually do not require the holders of such shares to participate in losses of the Company. Accordingly, in periods in which the Company reported a net loss, such losses were not allocated to such preferred securities. In periods in which the Company reported a net loss attributable to ordinary shareholders, diluted net loss per share attributable to ordinary shareholders is the same as basic net loss per share attributable to ordinary shareholders, since dilutive ordinary shares are not assumed to have been issued if their effect is anti‑dilutive.

Recently adopted accounting pronouncements

In February 2016, the FASB issued ASU No. 2016‑02, Leases (Topic 842) (“ASU 2016‑02”). This guidance revises existing practice related to accounting for leases under ASC Topic 840 Leases (“ASC 840”). ASU 2016‑02 requires lessees to recognize most leases on their balance sheet as a right‑of‑use asset and a lease liability. The lease liability is equal to the present value of lease payments and the right‑of‑use asset is based on the lease liability, subject to adjustment such as for initial direct costs. For income statement purposes, the new standard retains a dual model similar to ASC 840, requiring leases to be classified as either operating or finance. For lessees, operating leases will result in straight‑line expense (similar to current accounting by lessees for operating leases under ASC 840). In July 2018, the FASB issued ASU No. 2018‑11, Leases (Topic 842) Targeted Improvements, which provides an additional transition method that allows entities to initially apply the new standard at the adoption date and recognize a cumulative‑effect adjustment to the opening balance of retained earnings in the period of adoption without restating prior periods. The guidance is effective for annual reporting periods beginning after December 15, 2018 and interim periods within those fiscal years, and early adoption is permitted. The Company adopted the new standard on January 1, 2019 by applying the new lease requirements at the adoption date without restating prior periods. In connection with the adoption of ASU 2016‑02 the Company recorded an impact of approximately $2.7 million on its consolidated balance sheet to record right‑of‑use‑assets and $2.6 million to record lease liabilities on January 1, 2019, which are primarily related to the lease of the Company’s corporate headquarters in the U.K. and the lease of its office and laboratory space in Lexington, Massachusetts. The adoption of ASU 2016‑02 did not have a material impact on the Company’s results of operations or cash flows.

In June 2018, the FASB issued ASU No. 2018‑07, Compensation — Stock Compensation: Improvements to Nonemployee Share‑Based Payment Accounting (“ASU 2018‑07”) to simplify the accounting for share‑based payments to non‑employees by aligning it with the accounting for share‑based payments to employees, with certain exceptions. The new guidance expands the scope of ASC 718, Compensation — Stock Compensation, to include share‑based payments granted to non‑employees in exchange for goods or services used or consumed in an entity’s own operations and supersedes the guidance in ASC Topic 505‑50, Equity‑Based Payments to Non‑Employees. The guidance is effective for public business entities in annual periods beginning after December 15, 2018 and interim periods within those years. Early adoption is permitted. The Company adopted the new standard on January 1, 2019. The adoption did not have a material impact on the Company’s financial position, results of operations or cash flows.

In August 2018, the FASB issued ASU No. 2018‑15, Intangibles (Topic 350): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, which aligns the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. This standard also requires customers to amortize the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement. The Company early adopted this standard, as of April 1, 2019, on a prospective basis for applicable implementation costs. The adoption of this standard would not have had a material impact to historical accounting periods. The Company capitalized approximately $0.1 million of implementation cost for the year ended December 31, 2019.

Recently Issued Accounting Pronouncements

In December 2019, the FASB issued ASU 2019-12, “Income Taxes: Simplifying the Accounting for Income Taxes,” intended to simplify the accounting for income taxes by eliminating certain exceptions related to the approach for intraperiod tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The new guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The standard is effective for annual periods beginning after December 15, 2020 and interim periods within, with early adoption permitted. Adoption of the standard requires certain changes to primarily be made prospectively, with some changes to be made retrospectively. We are currently assessing the impact of this standard on our financial condition and results of operations.

In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”). ASU 2016-13 will change how companies account for credit losses for most financial assets and certain other instruments. For trade receivables, loans and held-to-maturity debt securities, companies will be required to recognize an allowance for credit losses rather than reducing the carrying value of the asset. ASU 2016-13 is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption is permitted. The Company is currently evaluating the potential impact that the adoption of ASU 2016-13 will have on the Company’s financial position and results of operations.

Fair value of financial assets and liabilities

12 Months Ended

Dec. 31, 2019

Fair value of financial assets and liabilities

Fair value of financial assets and liabilities

3. Fair value of financial assets and liabilities

The warrant liability for warrants to subscribe for convertible preferred shares was initially recorded at fair value upon the date of the warrants’ issuance and was subsequently remeasured to fair value at each reporting date (Note 7). Upon the closing of the IPO on May 28, 2019, warrants that were not exercised or expired in conjunction with the IPO automatically became warrants to subscribe for ordinary shares, and met the criteria to be classified as shareholders’ equity (deficit). As such, following the final remeasurement on May 28, 2019, the Company reclassified the carrying value of the outstanding warrant liability to additional paid-in-capital in the consolidated balance sheet. As such, there is no warrant liability at December 31, 2019.

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands):


	Fair Value Measurement
	as of December 31, 2018 using:
	Level 1		Level 2		Level 3		Total
Liabilities:
Warrant liability	$	—	$	—	$	4,804	$	4,804
	$	—	$	—	$	4,804	$	4,804

During the years ended December 31, 2019 and 2018, there were no transfers between levels.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Property and equipment, net

12 Months Ended

Dec. 31, 2019

Property and equipment, net

Property and equipment, net

4. Property and equipment, net

Property and equipment, net consisted of the following (in thousands):


	December 31,
	2019		2018
Laboratory equipment	$	4,326	$	3,356
Leasehold improvements		300		75
Computer equipment and software		229		221
Furniture and office equipment		120		99
		4,975		3,751
Less: Accumulated depreciation and amortization		(2,683)		(1,933)
	$	2,292	$	1,818

Depreciation expense was $1.0 million, $0.7 million and $0.3 million for the years ended December 31, 2019, 2018 and 2017, respectively.

Accrued expenses and other current liabilities

12 Months Ended

Dec. 31, 2019

Accrued expenses and other current liabilities

Accrued expenses and other current liabilities

5. Accrued expenses and other current liabilities

Accrued expenses and other current liabilities consisted of the following (in thousands):


	December 31,
	2019		2018
Accrued employee compensation and benefits	$	2,514	$	1,610
Accrued external research and development expenses		2,055		3,814
Income taxes payable		1		15
Accrued professional fees		867		1,494
Current portion of operating lease liabilities		640		—
Other		67		99
	$	6,144	$	7,032

Convertible preferred shares	12 Months Ended
Convertible preferred shares	Dec. 31, 2019
Convertible preferred shares
Convertible preferred shares	6. Convertible preferred shares The Company has issued Series A convertible preferred shares (“Series A Preferred Shares”), Series B1 convertible preferred shares (“Series B1 Preferred Shares”), and Series B2 convertible preferred shares (“Series B2 Preferred Shares”) (collectively the “Preferred Shares”). On May 26, 2017 the Company completed the issue of 3,562,583 Series B1 Preferred Shares at a price per share of £11.2278, for gross cash proceeds of $51.9 million. In addition, on October 27, 2017, an additional unaffiliated investor subscribed for a further 384,615 Series B1 Preferred Shares at a price per share of £13, for gross cash proceeds of $6.6 million. These two transactions are collectively referred to as “the Series B1 Financing”. In conjunction with the Series B1 Financing, the Company also issued warrants to subscribe for 743,287 Series B1 Preferred Shares to the subscribers of the Series B1 Preferred Shares (Note 7). The Company allocated a portion of the proceeds equal to the fair value of the warrants at the date of grant to the warrant liability, and the remaining amount was allocated to the Series B1 Preferred Shares. On December 20, 2018, the Company completed the issue of 1,323,248 Series B2 preferred shares at a price per Series B2 preferred share of £15.55, for gross cash proceeds of $26.1 million (the “Series B2 Financing”). In conjunction with the Series B2 Financing, the existing holders of warrants to subscribe for Series B1 preferred shares surrendered 194,911 warrants to subscribe for the same number of Series B1 preferred shares and the Company issued a further 194,911 warrants to subscribe for the same number of Series B1 preferred shares to the new investor. In conjunction with the Series B2 Financing, the Company designated all previously outstanding Series B preferred shares as Series B1 preferred shares. On January 3, 2019, the Company completed the issue of 80,385 Series B2 preferred shares at a price per share of £15.55, for gross cash proceeds of $1.6 million. Upon the closing of the IPO in May 2019, all of the Company’s outstanding convertible preferred shares automatically converted into 11,647,529 ordinary shares on a 1:1.429 basis.

Warrant liability

12 Months Ended

Dec. 31, 2019

Warrant liability

Warrant liability

7. Warrant liability

On May 26, 2017, the Company issued 200,000 warrants to subscribe for Series A Preferred Shares at £0.01 each, which are exercisable at any time after May 26, 2017 provided that they have not otherwise lapsed in accordance with their terms. The warrants to subscribe for Series A Preferred Shares expire upon the earlier of (i) 10 years from their issuance date, or (ii) upon an IPO or exit unless an exercise delay notice is provided by the Series A warrant holder, in which case they will expire 12 months following an IPO or exit. On May 28, 2019, in conjunction with the completion of the IPO, 120,000 warrants to subscribe for Series A Preferred Shares were exercised for 171,480 ordinary shares. The holders of the remaining 80,000 warrants provided the Company with an exercise delay notice, which are exercisable into 114,320 ordinary shares following the completion of the IPO, as adjusted for the impact of the Share Capital Reorganization (Note 1). As of December 31, 2019, 65,000 warrants are outstanding, which are exercisable into 92,885 ordinary shares.

On May 26, 2017, in conjunction with the issuance of 3,562,583 Series B1 Preferred Shares at a price per share of £11.2278, the Company issued 627,903 warrants to subscribe for Series B1 Preferred Shares with an exercise price of £0.01. In addition, on October 27, 2017, in conjunction with the issuance of 384,615 Series B1 Preferred Shares the Company issued a further 115,384 warrants to subscribe for Series B1 Preferred Shares with an exercise price of £0.01. In conjunction with the Series B2 Financing, the existing holders of warrants to subscribe for Series B1 preferred shares surrendered 194,911 warrants to subscribe for the same number of Series B1 preferred shares and the Company issued a further 194,911 warrants to subscribe for the same number of Series B1 preferred shares to the new investor. The transfer of warrants between investors did not have an impact to the valuation of the warrant liability, as this represents a transaction between shareholders and the Company did not issue any new instruments or change the rights and preferences of the underlying warrants to subscribe for Series B1 preferred shares.

On March 7, 2019, the holders of the Series B1 warrants to subscribe for Series B1 Preferred Shares agreed that 50% of the warrants would be exercised in conjunction with the IPO and 50% of the warrants would expire. The Company assessed this event as a modification to the terms of the Series B1 warrants and, remeasured the warrant liability immediately before and immediately after the modification, which resulted in an incremental change in fair value of $0.1 million, which is included in other expense for the year ended December 31, 2019. On May 28, 2019, in conjunction with the completion of the IPO, all Series B1 Preferred share warrants were exercised for 531,077 ordinary shares, as adjusted for the impact of the Share Capital Reorganization (Note 1).

Prior to the completion of the IPO, the warrants to subscribe for Series A and Series B1 Preferred Shares were recorded as a liability and remeasured to fair value at each reporting date (Note 3). Changes in the fair value of the warrant liability were recognized as other expense, net in the consolidated statements of operations and comprehensive loss. Upon the closing of the IPO on May 28, 2019, warrants that were not exercised in conjunction with the IPO automatically became warrants to subscribe for ordinary shares, and meet the criteria to be classified as shareholders’ equity (deficit). As such, following the final remeasurement on May 28, 2019, the Company reclassified the carrying value of the warrant liability to additional paid-in-capital in the consolidated balance sheet.

The following table provides a roll-forward of the fair values of the Company’s warrant liability for which fair value was determined by Level 3 inputs (in thousands):


	Warrant
	Liability
Fair value at December 31, 2018	$	4,804
Change in fair value of warrant liability recorded as other expense		5,381
Conversion of warrant liability to equity upon closing of IPO and exercise of warrants		(10,021)
Impact of exchange rates on translation of warrant liability to USD included in accumulated other comprehensive income (loss)		(164)
Fair value at December 31, 2019	$	—

The warrant liability in the table above consisted of the fair value of warrants to subscribe for Series A and Series B1 Preferred Shares (see Note 6) and, prior to the IPO, was based on significant inputs not observable in the market, which represent a Level 3 measurement within the fair value hierarchy. The Company’s valuation of the warrants to subscribe for Series A and Series B1 Preferred Shares utilized the Black‑Scholes option‑pricing model, which incorporates assumptions and estimates to value the warrant liability. The Company assessed these assumptions and estimates on a quarterly basis prior to the closing of the IPO in May 2019.

The quantitative elements associated with the Company’s Level 3 inputs impacting the fair value measurement of the warrant liability included the fair value per share of the underlying Series A and Series B1 preferred shares or ordinary shares at the time of final remeasurement, into which the warrants were exercisable, the remaining contractual term of the warrants, risk‑free interest rate, expected dividend yield and expected volatility of the price of the underlying convertible preferred shares.

The most significant assumption in the Black‑Scholes option‑pricing model impacting the fair value of the warrant liability was the fair value of the Series A and Series B1 preferred shares, or ordinary shares at the time of final remeasurement, into which the warrant is exercisable as of each remeasurement date. Given the absence of an active market for the Company’s equity securities prior to the IPO, the Company determined the fair value per share of the convertible preferred shares underlying the warrants by taking into consideration the implied value derived from an independent third‑party valuation of the Company’s ordinary shares, adjusted for certain restrictions on the exercise of the B1 warrants per their contractual terms. Assumptions related to the remaining term, risk-free interest rate, expected dividend yield and expected volatility did not have an impact to the fair value of the warrants because the exercise price of the warrants was £0.01, and the fair value of the warrant was equal to the difference between the exercise price and the fair value regardless of the assumptions. The Company historically had been a private company and lacked company‑specific historical and implied volatility information of its shares. Therefore, it estimated its expected share volatility based on the historical volatility of publicly traded peer companies for a term equal to the remaining contractual term of the warrants. The risk‑free interest rate was determined by reference to the U.S. Treasury yield curve for time periods approximately equal to the remaining contractual term of the warrants. The Company had estimated a 0% dividend yield based on the expected dividend yield and the fact that the Company has never paid or declared dividends. The following table presents the unobservable inputs to the fair value measurement of the warrant liability:


		Remeasurement upon closing
	of the IPO on May 28, 2019						December 31, 2018
	Series A			Series B1			Series A			Series B1
	Warrants			Warrants			Warrants			Warrants (1)
Risk-free rate		2.2	%		2.1	%		2.6	%		2.5	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected term (years)		8.0			5.8			8.4			6.25
Expected volatility		74.7	%		78.2	%		75.4	%		79.6	%
Exercise price	£	0.01		£	0.01		£	0.01		£	0.01
Fair value of preferred shares or ordinary shares underlying the warrant	$	12.28		$	12.28		$	8.61		$	4.15

⁽¹⁾

The fair value of the Series B1 preferred shares underlying the warrants to purchase Series B1 preferred shares at December 31, 2018 includes a 50% probability that the warrants will be not be exercisable prior to the IPO, based on their contractual terms.

Ordinary shares	12 Months Ended
Ordinary shares	Dec. 31, 2019
Ordinary shares
Ordinary shares	8. Ordinary shares Each holder of ordinary shares is entitled to one vote per ordinary share and to receive dividends when and if such dividends are recommended by the board of directors and declared by the shareholders. As of December 31, 2019 and 2018, the Company has not declared any dividends. As of December 31, 2019 and 2018, the Company’s authorized capital share consisted of 31,995,653 and 15,452,420 ordinary shares, respectively, with a nominal value of £0.01 per share.

Share-based compensation

12 Months Ended

Dec. 31, 2019

Share-based compensation

Share-based compensation

9. Share‑based compensation

Employee incentive pool

2019 Share Option Plan

In May 2019, the Company adopted the 2019 Share Option Plan (the “2019 Plan”), which became effective in conjunction with the IPO. In September 2019, the Compensation Committee of the Company’s Board of Directors approved immaterial clarifying amendments to the 2019 Plan which did not have an impact to the consolidated financial statements. The 2019 Plan provides for the grant of options to purchase ordinary shares and other share-based awards to officers, employees, directors and other key persons (including consultants).

The Company has initially reserved 2,470,583 ordinary shares for future issuance under the 2019 Plan. The number of ordinary shares reserved for issuance of the 2019 Plan will automatically increase on the first day of January, commencing on January 1, 2020, in an amount equal to 4% of the total number of ordinary shares outstanding on the last day of the preceding year, or a lesser number of shares determined by the Company’s board of directors, subject to adjustment in the event of a share split, share dividend or other change in capitalization. As of December 31, 2019, there were 872,646 shares available for issuance under the 2019 Plan. The number of shares reserved for issuance under the 2019 Plan was increased by 719,748 shares effective January 1, 2020.

Share options issued under the 2019 Share Option Plan have a 10 year contractual life, and either vest monthly over a three year service period, or over a four‑year service period with 25% of the award vesting on the first anniversary of the commencement date and the balance thereafter in 36 equal monthly installments. The exercise price of share options issued under the 2019 Share Option Plan shall not be less than the fair value of ordinary shares as of the date of grant.

Pre-IPO Share Options and restricted shares

Prior to the IPO, the Company issued share options and ordinary shares, as administered by the board of directors, using standardized share option and share subscription agreements. To the extent such incentives were in the form of share options, the options may have been granted pursuant to a potentially tax-favored Enterprise Management Incentive, or EMI, scheme available to U.K. employees, directors and consultants of the Company. Upon completion of the IPO, shares reserved for future issuance outside of the 2019 Share Option Plan were cancelled.

Options granted, as well as restricted shares granted as employee incentives prior to the IPO, typically vest over a four‑year service period with 25% of the award vesting on the first anniversary of the commencement date and the balance thereafter in 36 equal monthly installments and expire no later than 10 years from the date of grant.

Certain equity awards were issued in 2017 and 2018 for which 20% of the award vests upon the first anniversary of the vesting start date, 60% vests thereafter in 36 equal monthly installments, and 20% vest upon the earlier of the fourth anniversary of the vesting start date, or the achievement of a specified revenue threshold from the Company’s collaboration arrangements.

Options issued to U.K. employees prior to the IPO generally had an exercise price of £0.01 per share. The exercise price for share options granted to U.S. employees, had an exercise price that was not less than the fair value of ordinary shares as determined by the board of directors as of the date of grant. Prior to the IPO, the Company’s board of directors valued the Company’s ordinary shares based on input from management, considering the most recently available valuation of ordinary share performed by an independent third‑party valuation firm as well as additional factors which may have changed since the date of the most recent contemporaneous valuation through the date of grant.

Employee Share Purchase Plan (“ESPP”)

In May 2019, the Company adopted the 2019 Employee Stock Purchase Plan (“ESPP”), which became effective in conjunction with the IPO. The Company initially reserved 215,000 ordinary shares for future issuance under this plan. Each offering to the employees to purchase shares under the ESPP will begin on each June 1 and December 1 and will end on the following November 30 and May 31, respectively. On each purchase date, which falls on the last date of each offering period, ESPP participants will purchase ordinary shares at a price per share equal to 85% of the lesser of (1) the fair market value of the shares on the offering date or (2) the fair market value of the shares on the purchase date. The occurrence and duration of offering periods under the ESPP are subject to the determinations of the Company’s compensation committee. As of December 31, 2019, there have been no offering periods to employees under ESPP.

Share‑based compensation

The Company recorded share‑based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
Research and development expenses	$	1,286	$	513	$	241
General and administrative expenses		1,797		510		274
	$	3,083	$	1,023	$	515

Share options

The following table summarizes the Company’s option activity since December 31, 2018:


				Weighted
		Weighted		Average	Aggregate
	Number of	Average		Contractual	Intrinsic
	Shares	Exercise Price		Term	Value
				(in years)	(in thousands)
Outstanding as of December 31, 2018	863,712	$	1.01	8.75	$	3,292
Granted	2,134,538		12.01	—		—
Exercised	(85,839)		1.67	—		—
Forfeited	(278,065)		4.21	—		—
Outstanding as of December 31, 2019	2,634,346	$	9.57	9.04	$	6,107
Vested and expected to vest as of December 31, 2019	2,634,346	$	9.57	9.04	$	6,107
Options exercisable as of December 31, 2019	647,901	$	6.81	8.49	$	2,868

The weighted average grant‑date fair value of share options granted during the years ended December 31, 2019, 2018 and 2017 was $6.07 per share, $3.73 per share and $1.78 per share, respectively.

For the years ended December 31, 2019, 2018 and 2017, the Company recorded share‑based compensation expense for share options granted of $2.7 million, $0.8 million and $0.4 million, respectively. Expense for non‑employee consultants for the years ended December 31, 2019, 2018 and 2017, was immaterial.

The aggregate intrinsic value of share options is calculated as the difference between the exercise price of the share options and the fair value of the Company’s ordinary shares. The aggregate intrinsic value of share options exercised during the years ended December 31, 2019, 2018 and 2017 was $0.6 million, $23,000 and $7,000 respectively.

During the year ended December 31, 2019, 2018 and 2017, the Company granted certain performance based vesting options for the purchase of an aggregate of zero, 70,875 and 678,610 ordinary shares, respectively, for which 20% of the award vests upon the first anniversary of the vesting start date, 60% vests thereafter in 36 equal monthly installments, and 20% on the earlier of the fourth anniversary of the vesting start date, or the achievement of a specified revenue threshold from the Company’s collaboration arrangements. In May 2018, the Company determined that the performance condition became probable of achievement and recorded a cumulative catch‑up to reflect the expense as if the vesting condition was probable of achievement at the time of the grant of the award. The Company recorded expense of $0.1 million, $0.7 million and $0.3 million, during the year ended December 31, 2019, 2018 and 2017, respectively, related to these awards, which includes the acceleration of vesting expense.

The following table presents, on a weighted average basis, the assumptions used in the Black‑Scholes option‑pricing model to determine the fair value of share options granted to employees and directors:




	Year Ended
	December 31,
	2019		2018		2017
Risk-free interest rate	2.1	%	2.7	%	2.0	%
Expected volatility	77.9	%	78.6	%	79.7	%
Expected dividend yield	—		—		—
Expected term (in years)	5.86		6.07		6.07

As of December 31, 2019, total unrecognized compensation expense related to the unvested employee and director share‑based awards was $10.6 million, which is expected to be recognized over a weighted average period of 2.5 years.

Restricted shares

The Company has granted restricted shares with service‑based vesting conditions. Shares of unvested restricted shares may not be sold or transferred by the holder. These restrictions lapse according to the time‑based vesting conditions of each award. These restricted shares are subject to repurchase rights, for aggregate consideration of £1. Accordingly, the Company has recorded the proceeds from the issuance of restricted shares as a liability in the consolidated balance sheets included as a component of accrued expenses and other current liabilities. The restricted share liability is reclassified into shareholders’ (deficit) equity as the restricted shares vest.

The following table summarizes the Company’s restricted ordinary share award activity since December 31, 2018:


		Weighted Average
		Grant-Date
	Shares	Fair Value
Unvested restricted ordinary shares as of December 31, 2018	83,947	$	1.93
Issued	—		—
Forfeited	—		—
Vested	(83,947)		1.93
Unvested restricted ordinary shares as of December 31, 2019	—	$	—

In conjunction with the IPO in May 2019, the board of directors modified the vesting terms to accelerate vesting for all then unvested restricted shares. As a result, the Company recorded $0.2 million of expense upon the modification of the restricted shares during the year ended December 31, 2019.

For the years ended December 31, 2019, 2018 and 2017, the Company recorded share-based compensation of $0.4 million, $0.2 million, and $0.1 million, respectively, for unvested restricted shares granted.

The fair value of employee restricted share awards vested during the years ended December 31, 2019, 2018 and 2017, based on estimated fair values of the ordinary shares underlying the restricted share awards on the day of vesting, was $0.7 million, $0.2 million and $0.1 million, respectively.

As of December 31, 2019, there was no unrecognized compensation cost related to the unvested employee and director restricted share awards.

Significant Agreements

12 Months Ended

Dec. 31, 2019

Significant Agreements

Significant Agreements

10. Significant Agreements

For the years ended December 31, 2019, 2018 and 2017, the Company had collaboration agreements with AstraZeneca, Sanofi, (formerly Bioverativ), Oxurion (formerly ThromboGenics) and the Dementia Discovery Fund. The following table summarizes the revenue recognized in the Company’s consolidated statements of operations and comprehensive loss from these arrangements (in thousands):



	Year Ended
	December 31,
	2019		2018		2017
Collaboration revenues
AstraZeneca	$	1,683	$	1,386	$	890
Sanofi		10,724		4,007		355
Oxurion		—		1,743		815
Dementia Discovery Fund		394		—		—
Material transfer agreement		1,000		—		—
Total collaboration revenues	$	13,801	$	7,136	$	2,060

AstraZeneca Collaboration Agreement

Summary of Agreement — 2016 Agreement

In November 2016, the Company entered into a Research Collaboration Agreement (the “AstraZeneca Collaboration Agreement”) with AstraZeneca. The collaboration is focused on the research and development of Bicycle peptides that bind to up to six biological targets. After discovery and initial optimization of such Bicycle peptides, AstraZeneca will be responsible for all research and development, including lead optimization and drug candidate selection. AstraZeneca has option rights, at drug candidate selection, which allow it to obtain development and exploitation license rights with regard to such drug candidate. The initial research obligation focuses on two targets within respiratory, cardiovascular and metabolic disease. AstraZeneca also has an option to nominate up to four additional targets at any point up to the second anniversary of the agreement (“Additional Four Target Option”). The exercise of this option right results in an option fee payable to the Company of $5.0 million and the research obligations and rights are consistent with the obligations and rights related to the initial two targets discussed below.

Under the AstraZeneca Collaboration Agreement, the Company is obligated to use commercially reasonable efforts to perform research activities on the initial two targets, under mutually agreed upon research plans. The research plans includes two discrete parts, on a research program by research program basis: (i) the Bicycle Research Term, which is focused on the generation of Bicycle peptide libraries using the Company’s peptide drug discovery platform, to be screened against selected biological targets and optimization of promising compounds, with the goal of identifying compounds that meet the criteria set by the parties, and (ii) the AZ Research Term, during which AstraZeneca may select certain compounds and continue research activities on those compounds, at its sole expense, with the goal of identifying compounds that satisfy the relevant pharmacological and pharmaceutical criteria for clinical testing. AstraZeneca may, at its sole discretion, approve any compound to be progressed into drug development and, upon the selection of each drug candidate, AstraZeneca is to pay $8.0 million as an option fee, in order to obtain worldwide development and exploitation rights.

Each research program is to continue for an initial period of three years (the “Research Term”), including one year for the Bicycle Research Term and two for the AZ Research Term. AstraZeneca may extend the Research Term for each research program by twelve months (or fifteen months, if needed to complete certain toxicology studies). The Research Term for a specific program can be shorter if it is ceased due to a screening failure, a futility determination, abandonment by AstraZeneca, or upon selection of a drug candidate. AstraZeneca has certain substitution rights should a screening failure or futility determination be reached but is obligated to fund these additional efforts related to substitution.

Under the terms of the AstraZeneca Collaboration Agreement, the Company granted to AstraZeneca, for each research program, a right and license (with the right to sublicense) certain background and platform intellectual property, for the duration of the applicable Research Term, to the extent necessary or useful for AstraZeneca to conduct the activities assigned to it in the applicable research plan, but for no other purpose.

The activities under the AstraZeneca Collaboration Agreement are governed by a joint steering committee (“JSC”) formed by an equal number of representatives from the Company and AstraZeneca. The JSC oversees and reviews each research program. Among other responsibilities, the JSC monitors and reports on research progress and ensure open and frequent exchange between the parties regarding research program activities.

AstraZeneca is obligated to fund two full time equivalents (“FTE”) during the Bicycle Research Term, for each research program, based on an agreed upon FTE reimbursement rate. Payment is made quarterly in advance of services being provided.

AstraZeneca has the option to obtain development and commercialization licenses associated with each designated drug candidate in return for a fee of $8.0 million per drug candidate. In addition, AstraZeneca is required to make certain milestone payments to the Company upon the achievement of specified development, regulatory and commercial milestones. More specifically, for each research program, the Company is eligible to receive up to $29.0 million in development milestone payments and up to $23.0 million in regulatory milestone payments. The Company is also eligible for up to $110.0 million in commercial milestone payments, on a research program by research program basis. Development milestone payments are triggered upon initiation of a defined phase of clinical research for a drug candidate. Regulatory milestone payments are triggered upon approval to market a product candidate by the United States Food and Drug Administration (“FDA”) or other global regulatory authorities. Commercial milestone payments are triggered when an approved pharmaceutical product reaches certain defined levels of net sales by the licensee. In addition, to the extent any of the product candidates covered by the licenses conveyed to AstraZeneca are commercialized, the Company would be entitled to receive tiered royalty payments of mid‑single digits based on a percentage of net sales. Royalty payments are subject to certain reductions, including in certain countries where AstraZeneca faces generic competition. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, the Company may not receive any additional milestone payments or royalty payments from AstraZeneca.

Either party may terminate the AstraZeneca Collaboration Agreement if the other party has materially breached or defaulted in the performance of any of its material obligations and such breach or default continues after the specified cure period. Either party may terminate the AstraZeneca Collaboration Agreement in the event of the commencement of any proceeding in or for bankruptcy, insolvency, dissolution or winding up by or against the other party that is not dismissed or otherwise disposed of within a specified time period. AstraZeneca may terminate the AstraZeneca Collaboration Agreement, entirely or on a licensed product by licensed product or country by country basis, for convenience.

Accounting Analysis

The Company has identified the following performance obligations:

(i)

research license and the related research and development services during the Bicycle Research Term for the first target (the “Target One Research License and Related Services”),

(ii)

research license and the related research and development services during the Bicycle Research Term for the second target (the “Target Two Research License and Related Services”).

The Company concluded that the Additional Four Target Option is not a material right, as the option does not provide a discount that AstraZeneca otherwise would not have received. The Company’s participation in the joint steering committee was assessed as immaterial in the context of the contract. The Company has concluded that the research license is not distinct from the research and development services during the Bicycle Research Term as AstraZeneca cannot obtain the benefit of the research license without the Company performing the research and development services. The services incorporate proprietary technology and unique skills and specialized expertise, particularly as it relates to constrained peptide technology that is not available in the marketplace. As a result, for each research program, the research license has been combined with the research and development services into a single performance obligation.

The total transaction price was initially determined to be $1.2 million, consisting solely of research and development funding. The Company utilizes the most likely amount method to determine the amount of research and development funding to be received. Additional consideration to be paid to the Company upon the exercise of the license options by AstraZeneca or upon reaching certain milestones is excluded from the transaction price as they relate to option fees and milestones that can only be achieved subsequent to the option exercise or are outside of the initial contact term.

The Company will recognize revenue related to amounts allocated to the Research License and Related Services as the underlying services are performed over the one year Research Term using a proportional performance model over the period of service using input‑based measurements of total full‑time equivalent effort incurred to date as a percentage of total full‑time equivalent time expected and will remeasure its progress towards completion at the end of each reporting period, which best reflects the progress towards satisfaction of the performance obligation.

In October 2017, AstraZeneca selected a replacement target for the first target, and as such a new Research Term was started related to the Target One Research License and Related Services. In addition, both programs were extended. The total transaction price under the arrangement increased to $2.0 million for the additional research and development funding to be received.

For the years ended December 31, 2019, 2018 and 2017 the Company recognized $0.2 million, $1.0 million, and $0.9 million, respectively, of collaboration revenue related to the Target One and Target Two Research License and Related Services for its Collaboration Agreement with AstraZeneca. As of December 31, 2019 and 2018, the Company recorded zero deferred revenue, and $8,000 of deferred revenue, respectively, in connection with the 2016 AstraZeneca Collaboration Agreement.

May 2018 AstraZeneca Option Exercise — Additional Four Targets

Under the AstraZeneca Collaboration Agreement, AstraZeneca was granted an option to nominate up to four additional targets at any point up to the second anniversary of the agreement (“Additional Four Target Option”). In May 2018, AstraZeneca made an irrevocable election to exercise the Additional Four Target Option. As a result, AstraZeneca is entitled to obtain research and development services with respect to Bicycle peptides that bind to up to four additional targets, along with license rights to those selected targets, in exchange for an option fee of $5.0 million to be paid by AstraZeneca to the Company in January 2019. AstraZeneca is obligated to fund two FTEs during the Bicycle Research Term, for each research program, based on an agreed upon FTE reimbursement rate. Payment is made quarterly in advance of services being provided. AstraZeneca has the option to obtain worldwide development and commercialization licenses associated with each designated drug candidate in return for a fee of $8.0 million per drug candidate, upon the selection of such drug candidate, after which AstraZeneca would be required to fund development and commercialization costs, and to pay regulatory and commercial milestone payments and royalties to the Company as for the other products developed under the AstraZeneca Collaboration Agreement.

Accounting Analysis

Upon the execution of the agreement, the Company has identified the following five performance obligations associated with the AstraZeneca May 2018 Agreement:

(i)

Research license and the related research and development services during the Bicycle Research Term for the third target (the “Target Three Research License and Related Services”),

(ii)

Material right associated with the development and exploitation license option for the third target (“Target Three Material Right”),

(iii)

Material right associated with the research services option, including the underlying development and exploitation license option for the fourth target (“Target Four Material Right”),

(iv)

Material right associated with the research services option, including the underlying development and exploitation license option for the fifth target (“Target Five Material Right”), and

(v)

Material right associated with the research services option, including the underlying development and exploitation license option for the sixth target (“Target Six Material Right”).

The Company concluded that the fourth, fifth and sixth targets available for selection are options. Upon exercise, AstraZeneca will obtain a research license and the related research and development services and an option to a development and exploitation license. The Company has concluded that the research services option, including the underlying development and exploitation license options related to each respective target results in a material right as the option exercise fee related to the development and exploitation license contains a discount that AstraZeneca would not have otherwise received.

The research license and the related research and development services related to the fourth, fifth and sixth targets are not performance obligations, as they are optional services that will be performed if AstraZeneca selects additional targets and they reflect their standalone selling prices and do not provide the customer with material rights. The Company’s participation in the joint steering committee was assessed as immaterial in the context of the contract.

The total transaction price was initially determined to be $5.7 million, consisting of the $5.0 million option exercise fee and research and development funding of an estimated $0.7 million. The research and development funding is being provided based on the costs that are incurred to conduct the research and development services. The Company utilizes the most likely amount method to determine the amount of research and development funding to be received. Additional consideration to be paid to the Company upon the exercise of the license options by AstraZeneca or upon reaching certain milestones are excluded from the transaction price as they relate to option fees and milestones that can only be achieved subsequent to the license option exercise or are outside of the initial contact term.

The transaction price was allocated to the performance obligations based on the relative estimated standalone selling prices of each performance obligation. The estimated standalone selling prices for each Research License and Related Services obligation is primarily based on the nature of the services to be performed and estimates of the associated effort and costs of the services, adjusted for a reasonable profit margin what would be expected to be realized under similar contracts. The estimated standalone selling price for the material rights was determined based on the fees AstraZeneca would pay to exercise the license options, the estimated value of the License Option using comparable transactions, and the probability that (i) AstraZeneca would opt into the target development, and (ii) the license options would be exercised by AstraZeneca. Based on the relative standalone selling price, the allocation of the transaction price to the separate performance obligations is as follows (in thousands):


	Allocation of
Performance Obligations	Transaction Price
Target Three Research License and Related Services	$	650
Target 3 Material Right		1,504
Target 4 Material Right		1,204
Target 5 Material Right		1,165
Target 6 Material Right		1,127
	$	5,650

The Company will recognize revenue related to amounts allocated to the Target Three Research License and Related Services as the underlying services are performed using a proportional performance model over the period of service using input‑based measurements of total full‑time equivalent effort incurred to date as a percentage of total full‑time equivalent time expected, which best reflects the progress towards satisfaction of the performance obligation. The amount allocated to the material rights is recorded as deferred revenue and the Company will commence revenue recognition upon exercise of or upon expiry of the option. The optional future research license and the related research and development services related to the fourth, fifth and sixth targets reflect their standalone selling prices and do not provide the customer with a material right and, therefore, are not considered performance obligations and are accounted for as separate contracts. In June 2019, AstraZeneca selected a replacement target for the third target, and as such a new Research Term was started related to the Target Three Research License and Related Services. The total transaction price under the arrangement increased to $6.3 million for the additional research and development funding to be received. During the year ended December 31, 2019, the Company commenced research and development services related to the fourth and fifth targets.

For the year ended December 31, 2019, 2018 and 2017, the Company recognized $1.5 million, $0.4 million, and zero, respectively, of revenue related to the Target Three Research License and Related Service, and research and development services for the fourth target and fifth target related to the May 2018 AstraZeneca Option Exercise. As of December 31, 2019 and 2018, the Company recorded $4.9 million and $4.7 million, respectively, of deferred revenue in connection with the May 2018 AstraZeneca Option Exercise and related contracts.

Sanofi Collaboration Agreement (formerly Bioverativ)

Summary of Agreement

In August 2017, the Company entered into a Collaboration Agreement with Bioverativ Inc., which was acquired by Sanofi in March 2018 (“Sanofi”). Under the collaboration agreement with Sanofi (the “Sanofi Collaboration Agreement”), the Company was obligated to provide research and development services focused on up to three collaboration programs; (i) Sickle cell disease, (ii) Hemophilia, and (iii) and a third program (“Program 3”), which is an optional program, to be defined. The Company used its bicyclic peptide screening platform to perform research and development services for the programs and Sanofi had the ability to select a collaboration product for each program and obtain a license to develop and exploit the selected collaboration product for an additional option fee.

Under the Sanofi Collaboration Agreement, the Company was obligated to perform research activities on the initial two named collaboration programs, under mutually agreed upon research plans. The research and development services for each program consist of two stages. The first was an initial stage of screening for high affinity binders and affinity maturation of such binders to identify lead compounds led by the Company (the “BV Bicycle Research Term”). Upon the conclusion of the BV Bicycle Research Term, Sanofi could, at is sole discretion, select a certain number of collaboration compounds to move forward into the Joint Research Term. Upon selection of the collaboration compounds, Sanofi was required to pay an option fee. During the Joint Research Term, the Company and Sanofi would jointly conduct research and development activities which included lead optimization of lead compounds, in preparation for lead collaboration product nomination (“Joint Research Term”). Sanofi could, at its sole discretion, approve any compound to be progressed into drug development and upon the selection of each collaboration product candidate, Sanofi was obligated to pay $5.0 million as an option fee, in order to obtain worldwide development and exploitation rights for that collaboration product.

Each research program had an initial period of three years (the “Research Term”) unless a program was abandoned by Sanofi or extended for up to one year. The first year of each Research Term was the BV Bicycle Research Term and the remaining part of the Research Term, including any extensions of the Research Term, was the Joint Research Term.

Under the terms of the Sanofi Collaboration Agreement, the Company granted to Sanofi, for each collaboration program, a non‑exclusive, sublicensable (through multiple tiers), worldwide license under certain intellectual property of the Company to conduct the activities assigned to Sanofi in the applicable research plan for the duration of the applicable Research Term, but for no other purpose.

The activities under the Sanofi Collaboration Agreement were governed by a joint steering committee (“JSC”) formed by an equal number of representatives from the Company and Sanofi. The JSC oversaw, reviewed and recommend direction of each collaboration program and variations of or modifications to the research plans.

Under the terms of the Sanofi Collaboration Agreement, the Company received a $10.0 million up‑front cash payment. Additionally, prior to the initiation of the research plan for each collaboration program, Sanofi made a non‑refundable payment of $1.4 million for the Sickle cell program and $2.8 million for the Hemophilia program as payment for the Company’s services during the BV Bicycle Research Term. During the Joint Research Term, Sanofi was obligated to fund a minimum of two FTE’s based on an agreed upon FTE reimbursement rate and fund certain external costs incurred by the Company. Sanofi had the option to obtain development and commercialization licenses associated with each designated collaboration product candidate in return for a fee of $5.0 million per drug candidate. In addition, Sanofi was required to make certain milestone payments to the Company upon the achievement of specified development, regulatory and commercial events. More specifically, for each collaboration program, the Company was eligible to receive between $47.5 million and $67.0 million in development milestone payments for the Sickle Cell and Hemophilia programs, respectively, and up to $104.0 million in regulatory milestone payments for each program. In addition, the Company was eligible for up to $55.0 million in commercial milestone payments, on a research program by research program basis. Development milestone payments were triggered upon initiation of a defined phase of clinical research for a collaboration product. Regulatory milestone payments were triggered upon approval to market a product candidate by the FDA or other global regulatory authorities. Commercial milestone payments were triggered when an approved collaboration product reaches certain defined levels of net sales by the licensee. In addition, to the extent any of the collaboration products covered by the licenses conveyed to Sanofi were commercialized, the Company would be entitled to receive tiered royalty payments of mid‑single digits to low double digits based on a percentage of net sales. Royalty payments were subject to certain reductions, including for instances where Sanofi faces generic competition in certain countries.

Under the terms of the Collaboration Agreement, Sanofi was also provided with an option to obtain screening services on the additional Program 3 target upon making an option fee payment of $5.0 million in addition to a non‑refundable payment of $1.4 million as payment for the Company’s services related to Program 3 during the BV Bicycle Research Term. The option expired in November 2018 unexercised.

Either party could terminate the Sanofi Collaboration Agreement if the other party had materially breached or defaulted in the performance of any of its material obligations and such breach or default continues after the specified cure period. Either party could terminate the Sanofi Collaboration Agreement in the event of the commencement of any proceeding in or for bankruptcy, insolvency, dissolution or winding up by or against the other party that is not dismissed or otherwise disposed of within a specified time period. Sanofi could terminate the Sanofi Collaboration Agreement, entirely or on a program by program, licensed product by licensed product or country by country basis, for convenience upon not less than 30 days prior written notice to the Company.

Accounting Analysis

The Company identified the following four performance obligations associated with the Sanofi Collaboration Agreement:

(i)

Research License and the related research and development services during the BV Bicycle Research Term for Sickle cell program (the “Sickle Cell Research License and Related Services”),

(ii)

Research License and the related research and development services during the BV Bicycle Research Term for Hemophilia program (the “Hemophilia Research License and Related Services”),

(iii)

Material right associated with the sickle cell program development and exploitation license option (“Sickle Cell License Option Material Right”), and

(iv)

Material right associated with the hemophilia program development and exploitation license option (“Hemophilia License Option Material Right”).

The Company concluded that the option to obtain screening services on the additional Program 3 target was not a material right, as the option did not provide a discount that Sanofi otherwise would not have received. The Company’s participation in the joint steering committee was assessed as immaterial in the context of the contract. Research license and the related research and development services related to the Joint Research Term were not performance obligations at the inception of the arrangement, as they were optional services to be performed if Sanofi selected collaboration compounds for lead optimization. The amount paid by Sanofi for the services during the Joint Research Team did not reflect a discount that the customer would otherwise receive and did not provide the customer with material rights.

The total transaction price was initially determined to be $14.2 million, consisting of the $10.0 million upfront payment and non‑refundable research and development funding of $4.2 million. The Company could receive reimbursement of FTE costs and external costs associated with work under the Joint Research Term, milestone payments during the Joint Research Term, as well as upon exercise of the license options. These variable amounts were excluded from the transaction price as they related to fees and milestones that could only be achieved subsequent to the exercise of an option.

The transaction price was allocated to the performance obligations based on the relative estimated standalone selling prices of each performance obligation. The estimated standalone selling prices for the Research License and Related Services was primarily based on the nature of the services to be performed and estimates of the associated effort and costs of the services, adjusted for a reasonable profit margin what would be expected to be realized under similar contracts. The estimated standalone selling price for the material rights was determined based on the fees Sanofi would pay to exercise the license options, the estimated value of the license option using comparable transactions, and the probability that the license options would be exercised by Sanofi. Based on the relative standalone selling price, the allocation of the transaction price to the separate performance obligations was as follows (in thousands):


	Allocation of
Performance Obligations	Transaction Price
Sickle Cell Research License and Related Services	$	1,405
Hemophilia Research License and Related Services		2,811
Sickle Cell License Option Material Right		5,286
Hemophilia License Option Material Right		4,698
	$	14,200

The Company recognized revenue related to amounts allocated to the Sickle Cell and Hemophilia Research License and Related Services obligations as the underlying services were performed using a proportional performance model, over the period of service using input‑based measurements of total full‑time equivalent effort incurred to date as a percentage of total full‑time equivalent time expected, which best reflected the progress towards satisfaction of the performance obligation. The amount allocated to the material rights was recorded as deferred revenue, and the Company commenced revenue recognition when the underlying option was exercised or upon expiry of the option.

During the year ended December 31, 2019, Sanofi extended the research and development services on both programs. The arrangement consideration increased to $14.9 million. On March 28, 2019, Sanofi notified the Company that it would not exercise the Sickle Cell License Option. In addition, the collaboration with Sanofi was terminated effective October 23, 2019. As a result, deferred revenue related to amounts allocated to the Sickle Cell License Option Material Right of $5.3 million and the Hemophilia License Option Material Right of $4.7 were recognized during the year ended December 31, 2019. For the years ended December 31, 2019, 2018 and 2017, the Company recognized $10.7 million, $4.0 million and $0.4 million, respectively, of collaboration revenue related to its collaboration with Sanofi. As of December 31, 2019 and 2018, the Company recorded deferred revenue of zero and $9.9 million, respectively, related to its collaboration with Sanofi, respectively.

Oxurion Collaboration Agreement

Summary of Agreement

In August 2013, the Company entered into a Research Collaboration and License Agreement (the “Oxurion Collaboration Agreement”) with Oxurion. Under the Oxurion Collaboration Agreement, the Company is responsible for identifying Bicycle peptides related to the collaboration target, plasma kallikrein, for use in various ophthalmic indications. Oxurion is responsible for further development and product commercialization after the defined research screening is performed by the Company.

Under the Oxurion Collaboration Agreement, the Company is obligated to perform specified research activities in accordance with the research plan, which includes two stages. Stage I, now completed, focused on the screening of targets using the Company’s Bicycle peptide discovery platform with the goal of identifying compounds that meet the criteria set by the parties, and Stage II, now underway, during which Oxurion has continued research activities on selected Bicycle peptides with the goal of identifying compounds for further development and commercialization. The Company is not obligated or expected to perform any research services during Stage II of the research plan.

The Company granted certain worldwide intellectual property rights to Oxurion for the development, manufacture and commercialization of licensed compounds associated with plasma kallikrein. The Oxurion Collaboration Agreement provided for an upfront payment of €1.0 million and potential additional R&D funding, at an agreed upon FTE rate, should the research effort require more than one FTE or the research plan be amended or extended by Oxurion. In addition, Oxurion is required to make certain milestone payments to the Company upon the achievement of specified research, development, regulatory and commercial events. More specifically, for each collaboration program, the Company is eligible to receive up to €8.3 million in research and development milestones of which €1.8 million has been received as of December 31, 2019. In addition, the Company is eligible to receive up to €16.5 million upon achievement of certain regulatory milestone payments (e.g. €5 million for granting first regulatory approval in either the United States or EU for the first indication). In addition, to the extent any of the collaboration products covered by the licenses granted to Oxurion are commercialized, the Company would be entitled to receive tiered royalty payments of mid‑single digits based on a percentage of net sales. Due to the uncertainty of pharmaceutical development and the high historical failure rates generally associated with drug development, the Company may not receive any additional milestone payments or royalty payments from Oxurion.

Either party may terminate the Oxurion Collaboration Agreement if the other party has materially breached any of its material obligations and such breach continues after the specified cure period. Either party may terminate the Oxurion Collaboration Agreement in the event of the commencement of any proceeding in or for bankruptcy, insolvency, dissolution or winding up by or against the other party that is not dismissed or otherwise disposed of within a specified time period. Oxurion may terminate the Oxurion Collaboration Agreement, entirely or on a program by program, licensed product by licensed product or country by country basis, for convenience upon not less than 90 days prior written notice to the Company.

In November 2017, the parties executed the First Deed of Amendment to the Oxurion Collaboration Agreement (“First Amendment”). The First Amendment confirms that THR‑149 has been selected as a development compound under the Oxurion Collaboration Agreement. The First Amendment provided for additional research services to be performed by the Company related to the identification of two additional compounds for Oxurion, in its discretion, to select as development compounds. As for the work under the Oxurion Collaboration Agreement, the Company will perform the work under Stage I of the research plan which will be funded at a specified FTE rate, plus any direct out of pocket expenses, and Oxurion will be responsible for Stage II research and any development after the selection of a development compound. Additional milestones and royalties were added for the potential additional licensed compounds, consistent with those of the initial Oxurion Collaboration Agreement. The Company is not obligated or expected to perform any research services during Stage II of the research plan.

Accounting Analysis

Under the Oxurion Collaboration Agreement, all licenses were granted and research services to be provided by the Company were fully completed and revenue associated with those obligations was fully recognized prior to January 1, 2016. Under the First Amendment, the Company has identified a single performance obligation associated with the performance of research services associated with Stage I of the research plan for which the Company will be reimbursed for its services at a specified FTE reimbursement rate plus out of pocket costs which will be recognized on a proportional performance basis as the associated FTE efforts and costs are incurred, which best reflects the progress towards satisfaction of the performance obligation. None of the unpaid development or regulatory milestones have been included in the transaction price, as all milestone are not considered probable at December 31, 2019 and December 31, 2018.

For the years ended December 31, 2019, 2018 and 2017, the Company recognized zero, $1.7 million and $0.8 million, respectively, of revenue related to its agreements with Oxurion. As of December 31, 2018, the research services under the First Amendment were complete. The revenue recognized for the years ended December 2019, 2018 and 2017 includes zero, $1.2 million and $0.8 million, respectively, related to the achievement of developmental milestones during the advancement of the research by Oxurion into a Phase I clinical study. There was no deferred revenue recorded as of December 31, 2019 and 2018 in connection with the agreements with Oxurion.

Dementia Discovery Fund Agreement

In May 2019, the Company entered into a collaboration with the Dementia Discovery Fund (“DDF”) to use Bicycle technology for the discovery and development of novel therapeutics for dementia (the “DDF Collaboration Agreement”). In October 2019, the collaboration with DDF was expanded to include Oxford University’s Oxford Drug Discovery Institute (ODDI). Under the terms of the DDF Collaboration Agreement, the Company and DDF will collaborate to identify Bicycles that bind to clinically validated dementia targets (the “DDF Research Plan”). The Company is obligated to use commercially reasonable efforts to perform research activities under the DDF Research Plan. DDF shall not be directly engaged in the conduct of any research activities under the arrangement. ODDI will then profile these Bicycles in a range of target-specific and disease-focused assays to determine their therapeutic potential. The activities under the DDF Collaboration Agreement will be governed by a project advisory panel, composed of two representatives from the Company and DDF. The Research Advisory Panel will oversee, review and recommend direction for the Research Plans and variations of or modifications of research plans.

The Company received an upfront payment of $1.1 million in May 2019. The Company may receive up to an additional $0.7 million, upon achievement of certain milestones such as the identification of lead bicycle candidates with a certain affinity, which would be used to fund additional research and development services including lead optimization.

Intellectual property created by the collaboration shall be owned by the Company, and background intellectual property improvements shall be owned by the party from whose background intellectual property they exclusively relate. If promising lead compounds are identified, the Company, ODDI and DDF have the option (the “DDF Option”) to establish a jointly owned new company (“NewCo”) to advance the compounds through further development towards commercialization. NewCo will receive a royalty and milestone-bearing assignment and license of intellectual property from the Company for this purpose. The DDF Option is exercisable at any time until 90 days following the completion of the Research Plan and delivery of a final report. If DDF does not elect to exercise the DDF Option during the Option period, then DDF shall have no right in the collaboration intellectual property. NewCo will initially be owned 66% by the Company and 34% by DDF; however, the Company shall not be entitled to exercise more than 50% of the total voting rights related to its ownership interests. After completion of the DDF Option exercise, for a period of two years following the option exercise, NewCo shall have the right to initiate a new research program to develop up to three additional dementia targets, on a target by target basis, and the Company will be entitled to charge NewCo an agreed upon FTE rate for peptide screening and optimization for the active targets.

Either party may terminate the DDF Collaboration Agreement upon providing not less than 60 days written notice. A party may terminate the DDF Collaboration Agreement with immediate effect without notice if at any time the other party files for protection under bankruptcy or insolvency laws, makes an arrangement for the benefit of creditors, appoints a receiver, administrator, manager or trustee over its property, proposes a written agreement of composition or extension of its debts, is a party to any dissolution, winding-up or liquidation, or is in material breach that has not been remedied.

Accounting Analysis

The Company identified a single performance obligation associated with the performance of research and development services under the DDF Research Plan.

The Company concluded that the DDF Option is an immaterial obligation at the inception of the arrangement, as it represents a right to acquire shares of NewCo that have de minimis value. The DDF Option also does not contain a material right that otherwise would not have been received. The Company’s participation in the Research Advisory Panel was assessed as immaterial in the context of the contract. In addition, the Company concluded that the option for NewCo to obtain additional peptide screening and optimization services is not an obligation at the inception of the arrangement, as they are optional services and the amount that will be paid for the services do not reflect a discount that the customer would otherwise receive and do not provide the customer with material rights.

The total transaction price was initially determined to be $1.1 million, consisting of the upfront payment for research and development funding. The Company may receive additional milestone payments during the DDF Research Plan, as well as for research and development services for additional targets following the exercise of DDF Option. These variable amounts are excluded from the transaction price as they relate to fees that can only be achieved subsequent to the exercise of an option.

The transaction price was allocated to the single performance obligation of research and development services. The Company will recognize revenue as the underlying services are performed using a proportional performance model, over the period of service using input‑based measurements of total costs, including total full‑time equivalent effort incurred to date as a percentage of total costs expected, which best reflects the progress towards satisfaction of the performance obligation.

For the year ended December 31, 2019, the Company recognized $0.4 million of revenue, and recorded deferred revenue of $0.7 million for the year ended December 31, 2019 related to its collaboration with DDF.

Material Transfer Agreement

In October 2018, the Company entered into a Materials Transfer Agreement. Under the terms of the agreement, the Company agreed to transfer bicyclic peptides (the “Materials”) to the recipient for the purpose of testing the materials in order to evaluate the Company’s technology platform. The recipient agreed to pay the Company $1.0 million within 30 business days after receipt of the materials and related data package, which was paid to the Company in May 2019. The agreement has a term of 14 months after delivery of the Materials and data package and may be terminated upon 45 days’ notice by the recipient. At any point during the term of the agreement and continuing through two months after the completion of the permitted research, the recipient has the option to enter into good faith negotiations to obtain a license to the Company’s background intellectual property and/or the Company’s interest in the new substances or developments for the purpose of continued research and development of collaboration products.

For the year ended December 31, 2019 and 2018, the Company recognized $1.0 million and zero, respectively, of revenue related to its Materials Transfer Agreement, as the Company concluded that the recipient has the ability to direct the use of and obtain substantially all of the remaining benefit from the Materials upon the delivery of the Materials and the data package.

Summary of Contract Assets and Liabilities

Up‑front payments and fees are recorded as deferred revenue upon receipt or when due until such time as the Company satisfies its performance obligations under these arrangements. A contract asset is a conditional right to consideration in exchange for goods or services that the Company has transferred to a customer. Amounts are recorded as accounts receivable when the Company’s right to consideration is unconditional.


	Balance at						Impact of		Balance at
	Beginning of						Exchange		End of
	Period		Additions		Deductions		Rates		Period
Period ended December 31, 2019
Contract assets	$	—	$	149	$	(149)	$	—	$	—
Contract liabilities:
Deferred revenue
AstraZeneca collaboration deferred revenue		4,727		58		(35)		163		4,913
Sanofi collaboration deferred revenue		9,908		—		(9,984)		76		—
DDF collaboration deferred revenue		—		1,114		(394)		24		744
Total deferred revenue	$	14,635	$	1,172	$	(10,413)	$	263	$	5,657

The following table presents changes in the balances of the Company’s contract assets and liabilities (in thousands):


	Balance at						Impact of		Balance at
	Beginning of						Exchange		End of
	Year		Additions		Deductions		Rates		Period
Period ended December 31, 2018
Contract assets	$	—	$	91	$	(91)	$	—	$	—
Contract liabilities:
Deferred revenue
AstraZeneca collaboration deferred revenue		—		5,350		(466)		(157)		4,727
Sanofi collaboration deferred revenue		14,467		—		(4,006)		(553)		9,908
Total deferred revenue	$	14,467	$	5,350	$	(4,472)	$	(710)	$	14,635

The contract assets represents research and development services which have been performed but have not yet been billed, and are reduced when they are subsequently billed.

The AstraZeneca deferred revenue balance as of December 31, 2019 includes $4.9 million allocated to the Target 3, Target 4, Target 5 and Target 6 Material Rights, which will commence revenue recognition when the respective option is exercised at the end of AZ Research Term or when the option expires. The remaining balance relates to research and development services billed in advance that will be recognized over the Bicycle Research Term.

During the year ended December 31, 2019, 2018 and 2017, the Company recognized the following revenues as a result of changes in the contract asset and the contract liability balances in the respective periods (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
Revenue recognized in the period from:
Revenue recognized based on proportional performance	$	(429)	$	(4,472)	$	(355)
Revenue recognized based on expiration of material rights		(9,984)		—		—
Total	$	(10,413)	$	(4,472)	$	(355)

Cancer Research UK

BT1718

On December 13, 2016, the Company entered into a Clinical Trial and License Agreement with Cancer Research Technology Limited (“CRTL”) and Cancer Research UK (“CRUK”). Pursuant to the agreement, as amended in March 2017 and June 2018, CRUK’s Centre for Drug Development will sponsor and fund a Phase Ia and Phase IIa clinical trial for the Company’s lead product candidate, BT1718, a Bicycle Toxin Conjugate, in patients with advanced solid tumors.

CRUK is responsible to design, prepare, carry out and sponsor the clinical trial at its cost. The Company is responsible for supplying agreed quantities of GMP materials for the study, the supply of which has been completed. In the event that additional quantities are needed, the Company will provide CRUK with all reasonable assistance to complete the arrangements necessary for the generation and supply of such additional GMP materials but CRUK will be responsible for supplying and paying for such additional quantities of GMP materials.

The Company granted CRUK a license to its and its affiliates’ intellectual property in order to design, prepare for, sponsor, and carry out the clinical trial the Company retains the right to continue the development of BT1718 during the clinical trial. Upon the completion of the Phase I/IIa clinical study, the Company has the right to obtain a license to the results of the clinical trial upon the payment of a milestone, in cash and ordinary shares, with a combined value in the mid six digit dollar amount. If such license is not acquired, or if it is acquired and the license is terminated and the Company decides to abandon development of all products that deliver cytotoxic payloads to the MT1 target antigen, the CRTL may elect to receive an exclusive license to develop and commercialize the product on a revenue sharing basis (in which case the Company will receive tiered royalties of 70% to 90% of the net revenue depending on the stage of development when the license is granted). The CRUK agreement contains additional future milestone payments upon the achievement of development and regulatory milestones, payable in cash and shares, with an aggregate total value of $50.9 million, as well as royalty payments based on a single digit percentage on net sales of products developed.

The CRUK agreement can be terminated by either party upon an insolvency event, material breach of the terms of the contract, or upon a change in control (and the new controlling entity generates its revenue from the sale of tobacco products or is an affiliate of such party). CRUK may terminate the arrangement for safety reasons or if it determines that the objectives of the clinical trial will not be met, in which case, if the study is terminated by CRUK prior to the completion of the Phase 1a dose escalation portion of the study for such reasons or if CRUK refuses release of any additional quantities of GMP materials or if the parties cannot agree upon a plan to supply the additional quantities of GMP materials, the Company will be obligated to refund fifty percent of the costs and expenses incurred or committed by CRUK to perform the clinical trial. If the study is terminated by CRUK for an insolvency event, a material breach by the Company, or if the Company is acquired by an entity that generates its revenue from the sale of tobacco products or is an affiliate of such party, the Company will reimburse CRUK in full for all costs paid or committed in connection with the clinical trial and no further license payments, where applicable, shall be due. In such case where we are acquired by an entity that generates its revenue from the sale of tobacco products or is an affiliate of such party, CRUK will not be obliged to grant a license to the Company in respect of the results of the clinical trial and the CRT may elect to receive an exclusive license to develop and commercialize the product without CRT being required to make any payment to the Company.

The Company concluded that the costs incurred by CRUK is a liability in accordance with ASC 730, Research and Development, as the payment is not based solely on the results of the research and development having future economic benefit. As such, for the year ended December 31, 2019 and 2018, the Company recorded a liability of $2.0 million and $0.8 million, respectively, which is recorded in other long‑term liabilities in the consolidated balance sheets. The liability is recorded as incremental research and development expense in the statements of operations and comprehensive loss.

BT7401

In December 2019, the Company entered into a clinical trial and license agreement with the Cancer Research Technology Limited and CRUK. Pursuant to the agreement, CRUK’s Centre for Drug Development will fund and sponsor development of BT7401 from current preclinical studies through the completion of a Phase IIa trial in patients with advanced solid tumors.

The Company granted to CRUK a license to our intellectual property in order to design, prepare for, sponsor, and carry out the clinical trial and all necessary preclinical activities to support the trial. The Company retains the right to continue the development of BT7401 during the clinical trial. Upon the completion of the Phase I/IIa clinical study, the Company has the right to obtain a license to the results of the clinical trial upon the payment of a milestone, in cash and ordinary shares, with a combined value in the mid six digit dollar amount. If such license is not acquired, or if it is acquired and the license is terminated and the Company decides to abandon development of all products that contain BT7401 or all the pharmaceutically active parts of BT7401, the Cancer Research Technology Limited may elect to receive an exclusive license to develop and commercialize the product on a revenue sharing basis (in which case the Company will receive tiered royalties of 55% to 80% of the net revenue depending on the stage of development when the license is granted) less certain costs, as defined by the agreement. The CRUK agreement contains additional future milestone payments upon the achievement of development, regulatory and commercial milestones, payable in cash, with an aggregate total value of up to $60.3 million for each licensed product, as well as royalty payments based on a single digit percentage on net sales of products developed, and sublicense royalties to the CRUK in the very low double digit percentage of sublicense income depending on the stage of development when the license is granted.

The CRUK agreement can be terminated by either party upon an insolvency event, material breach of the terms of the contract, or upon a change in control (and the new controlling entity generates its revenue from the sale of tobacco products), or upon written notice by either party prior to the last cycle of treatment has been completed under the clinical trial. If the study is terminated by the Company prior to the filing of a clinical trial authorization, or by the CRUK for an insolvency event or a material breach by us prior to the start of a clinical trial, the Company will reimburse CRUK for certain costs paid or committed prior to the start of the clinical trial. In such case where the Company is acquired by an entity that generates its revenue from the sale of tobacco products, CRUK will not be obliged to grant a license to us in respect of the results of the clinical trial and the Cancer Research Technology Limited may elect to receive an exclusive license to develop and commercialize the product without Cancer Research Technology Limited being required to make any payment to the Company. There were no activities initiated under the BT7401 CRUK arrangement as of December 31, 2019, and as such there was no accounting impact as of and for the year ended December 31, 2019.

Income Taxes

12 Months Ended

Dec. 31, 2019

Income Taxes

Income Taxes

11. Income Taxes

The components of net loss before tax provision from income taxes are as follows (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
United Kingdom	$	(31,906)	$	(22,229)	$	(16,319)
United States		1,044		(13)		37
Total	$	(30,862)	$	(22,242)	$	(16,282)

The components of the benefit for income taxes are as follows (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
Current income tax provision (benefit)
Federal	$	49	$	(25)	$	75
State		61		7		10
Total current income tax provision (benefit)		110		(18)		85
Deferred income tax (benefit) provision
Federal		(295)		(167)		(58)
State		(69)		(211)		(50)
Total deferred income tax (benefit)		(364)		(378)		(108)
Total benefit from income taxes	$	(254)	$	(396)	$	(23)

A reconciliation of the benefit for income taxes computed at the statutory income tax rate to the benefit for income taxes as reflected in the financial statement is as follows:


	Year Ended
	December 31,
	2019		2018		2017
Benefit for income taxes at statutory rate	19.0	%	19	%	19	%
(Decreases) increases resulting from:
Federal tax credits	1.3	%	1.1	%	0.4	%
Change in valuation allowance	(8.0)	%	(7.2)	%	(9.4)	%
Net losses surrendered for research credit	(5.3)	%	(3.7)	%	(6.7)	%
Preferred share warrants	(3.3)	%	(0.6)	%	(1.1)	%
Other	(2.9)	%	(6.8)	%	(2.1)	%
Effective income tax rate	0.8	%	1.8	%	0.1	%

Significant components of the Company’s current and deferred tax assets at December 31, 2019 and 2018, were as follows (in thousands):


	Year Ended
	December 31,
	2019		2018
Deferred tax assets:
Operating loss carryforwards	$	7,082	$	4,953
Research credit carryforwards		434		197
Operating lease liability		439		—
Accrued expenses and other		1,779		1,149
Total deferred tax assets		9,734		6,299
Deferred tax liabilities:
Operating lease right-of-use asset		(422)		—
Depreciation & amortization		(326)		(163)
Total deferred tax liabilities		(748)		(163)
Valuation allowance		(8,104)		(5,621)
Net deferred tax assets	$	882	$	515

During the years ended December 31, 2019, 2018 and 2017, the Company recorded an income tax benefit of $0.3 million, $0.4 million and $23,000, respectively. The Company is subject to United Kingdom corporate taxation. Due to the nature of its business, the Company has generated losses since inception and therefore not paid United Kingdom corporation tax. The Company's income tax benefit is mainly the result of deferred tax assets benefited in the United States that do not have a valuation allowance against them because of profits that will be generated by an intercompany service agreement.

The Company regularly assesses its ability to realize its deferred tax assets. Assessing the realization of deferred tax assets requires significant judgment. In determining whether its deferred tax assets are more likely than not realizable, the Company evaluated all available positive and negative evidence, and weighed the evidence based on its objectivity. After consideration of the evidence, including the Company's history of cumulative net losses in the U.K., and has concluded that it is more likely than not that the Company will not realize the benefits of its U.K. deferred tax assets and accordingly the Company has provided a valuation allowance for the full amount of the net deferred tax assets in the U.K. The Company has considered the Company's history of cumulative net profits in the United states, estimated future taxable income and concluded that it is more likely than not that the Company will realize the benefits of its United States deferred tax assets and has not provided a valuation allowance against the net deferred tax assets in the United States. The valuation allowance increased in the year ended December 31, 2019 by $2.5 million due to the corresponding increase in UK deferred tax assets, primarily due to operating loss carryforwards generated during the year that were not surrendered for research credit utilization.

The Company recorded a valuation allowance against all of its U.K. deferred tax assets as of December 31, 2019 and 2018.

The Company intends to continue to maintain a full valuation allowance on its U.K. deferred tax assets until there is sufficient evidence to support the reversal of all or some portion of these allowances. The release of the valuation allowance would result in the recognition of certain deferred tax assets and an increase to the benefit for income taxes for the period the release is recorded. However, the exact timing and amount of the valuation allowance release are subject to change on the basis of the level of profitability that the Company is able to actually achieve.

The benefit for income taxes shown on the consolidated statements of operations differs from amounts that would result from applying the statutory tax rates to income before taxes primarily because of certain permanent expenses that were not deductible, U.K., federal and state research and development credits, as well as the application of valuation allowances against the U.K. deferred tax assets.

As of December 31, 2019, the Company had $41.7 million of U.K. operating loss carryforwards and zero of federal and state net operating loss carryforwards. Unsurrendered U.K. losses may be carried forward indefinitely to be offset against future taxable profits, subject to numerous utilization criteria and restrictions. The amount that can be offset each year is limited to £5.0 million plus an incremental 50% of U.K. taxable profits. As of December 31, 2019, the Company had $0.3 million and $0.2 million of federal and state research and development credit carryforwards, respectively, that expire at various dates through 2039.

The Company recognizes, in its consolidated financial statements, the effect of a tax position when it is more likely than not, based on the technical merits, that the position will be sustained upon examination. The Company had no uncertain tax positions during the years ended of December 31, 2019 and 2018. There are no amounts of interest or penalties recognized in the consolidated statement of operations or accrued on the consolidated balance sheet for any period presented. The Company does not expect any material changes in these uncertain tax benefits within the next 12 months.

The Company files income tax returns in the United Kingdom, and in the United States for federal income taxes and in the Commonwealth of Massachusetts for state income taxes. In the ordinary course of business, the Company is subject to examination by tax authorities in these jurisdictions. The 2017 and 2018 tax year remains open to examination the by HM Revenue & Customs. The statute of limitations for assessment with the Internal Revenue Service is generally three years from filing the tax return. As such, all years since inception in the U.S. remain open to examination. The Company is currently not under examination by jurisdictions for any tax years.

Commitments and Contingencies

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies

Commitments and Contingencies

12. Commitments and Contingencies

Leases

In September 2015, the Company entered into a tenancy agreement for space in Building 260 Babraham Research Campus, Cambridge, UK for a period of two years, beginning on October 1, 2015. The annual rent was approximately $0.2 million plus service charges. In October 2017 this agreement was extended until January 2018 with annual rent of approximately $0.2 million.

In January 2017, Bicycle Therapeutics Inc. entered into a lease for office and laboratory space in Cambridge, Massachusetts for the period from February 1, 2017 to December 31, 2017. Rental payments under the lease were $19,500 per month, plus a portion of the landlords operating costs.

In September 2017, Bicycle Therapeutics Inc. entered into a lease agreement for office and laboratory space in Lexington, Massachusetts, which commenced on January 1, 2018 and expires on December 31, 2022. Bicycle Therapeutics Inc. has the option to extend for a successive period which is not included in the lease term as it is not reasonably certain that the option will be exercised. In conjunction with the lease agreement, Bicycle Therapeutics Inc. paid a security deposit of $0.2 million as well as prepaid rent of $0.1 million for the first month of the third, fourth, and fifth year of the lease. The deposit is recorded in other assets in the consolidated balance sheets. With the adoption of ASU 2016‑02, the Company has recorded a right‑of‑use asset (inclusive of the impact of prepaid rent) and corresponding lease liability, by calculating the present value of lease payments, discounted at 9%, the incremental borrowing rate, over the lease term.

In October 2017, the Company entered into a lease agreement for office and laboratory space in Building 900, Babraham Research Campus, Cambridge, U.K., which expires on December 21, 2021. The annual rent is approximately $0.5 million. The Company has the right to renew the lease for five years commencing December 21, 2021, which is not included in the lease term as it is not reasonably certain that the right will be exercised. Service charges are also payable based on floor area and are estimated to be approximately $0.1 million per year. In conjunction with the 2017 lease agreement, the Company paid a security deposit of $0.6 million, which is recorded in other assets in the consolidated balance sheets. With the adoption of ASU 2016‑02, the Company has recorded a right‑of‑use asset and corresponding lease liability, by calculating the present value of lease payments, discounted at 7.75%, the incremental borrowing rate, over the lease term.

The future minimum lease payments due under the Company’s operating leases as of December 31, 2018 under ASC 840 were as follows (in thousands):


Year Ending December 31,
2019	$	888
2020		901
2021		915
2022		483
2023		—
	$	3,187

Prior to the adoption of ASU 2016‑02 and for the year ended December 31, 2018 and 2017 the Company recognized rent expense on a straight‑line basis over the lease period and recorded deferred rent for rent expense incurred but not yet paid. During year ended December 31, 2018 and 2017, the Company recognized total rent expense of $1.0 million and $0.5 million, respectively.

The Company identified and assessed the following significant assumptions in recognizing the right‑of‑use assets and corresponding lease liabilities:

Expected lease term — The expected lease term includes both contractual lease periods and, when applicable, cancelable option periods when it is reasonably certain that the Company would exercise such options. The Company has not included any option periods in the expected lease term as it is not reasonably certain that the Company will exercise such options.

Incremental borrowing rate — The Company’s lease agreements do not provide an implicit rate. As the Company does not have any external borrowings for comparable terms of its leases, the Company estimated the incremental borrowing rate by comparing interest rates available in the market for similar borrowings and third‑party quotations.

Lease and non‑lease components — In certain cases, the Company is also responsible for certain additional charges for operating costs, including insurance, maintenance, taxes, and other costs incurred, which are billed based on both usage and as a percentage of the Company’s share of total square footage. The amounts paid are considered non‑lease components. The Company has elected the practical expedient which allows the non‑lease components to be combined with the lease components. The payments for other operating costs are considered variable lease cost and are recognized in the period in which the costs are incurred.

The components of the Company’s lease expense, which are recorded as a component of research and development expenses and general and administrative expenses in the consolidated statement of operations and comprehensive loss are as follows (in thousands):


	December 31,
	2019
Operating lease cost	$	900
Variable lease cost		390
Total lease cost	$	1,290
Weighted‑average remaining operating lease term (years)		2.6
Weighted‑average discount rate		8.52	%

Future minimum lease payments under non-cancelable operating leases under ASC 842 as of December 31, 2019 are as follows (in thousands):


Year Ending December 31,
2020	$	879
2021		777
2022		443
2023		—
2024		—
Present value adjustment		(208)
Total lease liabilities	$	1,891
Less: current lease liabilities		(640)
Long term lease liabilities	$	1,251

The Company has entered into various agreements with contract manufacturing organizations to provide clinical trial materials and with vendors for preclinical research studies, synthetic chemistry and other services for operating purposes. These payments are not included in the table of operating lease payments above since the contracts are generally cancelable at any time upon less than 90 days’ prior written notice. The Company is not contractually able to terminate for convenience and avoid any and all future obligations to these vendors. Under such agreements, the Company is contractually obligated to make certain minimum payments to the vendors, with the payments in the event of a termination with less than 90 days’ notice based on the timing of the termination and the exact terms of the agreement.

Legal proceedings

From time to time, the Company or its subsidiaries may become involved in various legal proceedings and claims, either asserted or unasserted, which arise in the ordinary course of business.

In September 2016, the Company’s subsidiary, BicycleRD, filed a complaint in the District Court of the Hague against Pepscan Systems B.V. and its affiliates (“Pepscan”) to contest the right of Pepscan to terminate a non‑exclusive patent license agreement entered into with Pepscan in 2009 (“PLA”). BicycleRD included a conditional claim for a ruling that the licensed patent relevant to BicycleRD’s activities is invalid. In response, Pepscan counterclaimed for injunctive relief and unquantified damages. The Company is vigorously prosecuting its claims and defending against those of Pepscan. The Company does not believe that a loss is probable or estimable at this time, and as such, the Company has not recorded a liability related to the Pepscan litigation as of December 31, 2019 or 2018. Should the Company not be successful in maintaining its rights to Pepscan’s patent or in the Company’s alternative demand that the patent be invalidated, commercialization of the Company’s lead product could be delayed. As the Pepscan patent expires prior to the expected commercialization date of the product, the Company does not believe that the legal proceedings could have a material adverse effect on the Company’s business and operating results.

Founder Royalty arrangements

At the time BicycleRD Limited was organized, BicycleRD Limited entered into a royalty agreement with its founders and initial investors (the “Founder Royalty Agreement”). Pursuant to the Founder Royalty Agreement, the Company will pay a royalty rate in the low single digit percentages on net product sales to its founders and initial investors, for a period of 10 years from the first commercial sale on a country by country basis. No royalties have been earned or paid under the royalty arrangements to date.

In accordance with the terms of the Founder Royalty Agreements, as amended in May 2017, the parties amended the terms of the royalty arrangements to limit the future royalties payments to net sales on future products that could be generated under the collaboration with Oxurion and AstraZeneca, in exchange for the issuance of warrants to subscribe for 200,000 Series A Preferred Shares. The Company recorded the fair value of the warrants to subscribe for Series A Preferred Shares to the founders of $0.9 million as research and development expense during the year ended December 31, 2017, as the licenses do not have alternative future use, in accordance with ASC Topic 730, Research and Development.

Indemnification obligations

In the ordinary course of business, the Company may provide indemnification of varying scope and terms to vendors, lessors, business partners and other parties with respect to certain matters including, but not limited to, losses arising out of breach of such agreements or from intellectual property infringement claims made by third parties. In addition, the Company has indemnification obligations towards members of its board of directors that will require the Company, among other things, to indemnify them against certain liabilities that may arise by reason of their status or service as directors or officers. The maximum potential amount of future payments the Company could be required to make under these indemnification arrangements is, in many cases, unlimited. To date, the Company has not incurred any material costs as a result of such indemnification obligations. The Company is not aware of any claims under indemnification arrangements, and therefore it has not accrued any liabilities related to such obligations in its consolidated financial statements as of December 31, 2019 and 2018.

Net loss per share

12 Months Ended

Dec. 31, 2019

Net loss per share

Net loss per share

13. Net loss per share

Basic and diluted net loss per share attributable to ordinary shareholders was calculated as follows (in thousands, except share and per share amounts):


	Year Ended
	December 31,
	2019		2018		2017
Numerator:
Net loss attributable to ordinary shareholders	$	(30,608)	$	(21,846)	$	(16,259)
Denominator:
Weighted average ordinary shares outstanding, basic and diluted		11,045,370		438,862		333,125
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(2.77)	$	(49.78)	$	(48.81)

The Company’s potentially dilutive securities, which include share options, warrants to subscribe for ordinary shares, and which prior to the completion of the IPO, included convertible preferred shares, warrants to subscribe for Series A and Series B1 Preferred Shares, and unvested restricted shares, have been excluded from the computation of diluted net loss per share as the effect would be to reduce the net loss per share. Therefore, the weighted average number of ordinary shares outstanding used to calculate both basic and diluted net loss per share attributable to ordinary shareholders is the same. The Company excluded the following potentially dilutive ordinary shares, presented based on amounts outstanding at each period end, from the computation of diluted net loss per share attributable to ordinary shareholders for the periods indicated because including them would have had an anti‑dilutive effect:


	Year Ended
	December 31,
	2019	2018	2017
Convertible preferred shares (as converted to ordinary shares)	—	11,532,659	9,641,740
Warrants to subscribe for convertible preferred shares (as adjusted to reflect the impact of the share capital reorganization and issuance of bonus shares (Note 1))(1)(2)	92,885	1,347,953	1,347,953
Restricted ordinary shares	—	83,947	162,466
Options to purchase ordinary shares	2,634,346	863,712	964,538
	2,727,231	13,828,271	12,116,697

⁽¹⁾

⁽²⁾

At December 31, 2019 65,000 warrants are outstanding which are exercisable into 92,885 ordinary shares (Note 6).

Benefit plans	12 Months Ended
Benefit plans	Dec. 31, 2019
Benefit plans
Benefit plans	14. Benefit plans The Company established a defined‑contribution savings plan under Section 401(k) of the Code (the “401(k) Plan”). The 401(k) Plan covers all U.S. employees and allows participants to defer a portion of their annual compensation on a pre‑tax basis. Matching contributions to the 401(k) Plan may be made at the discretion of the Company’s board of directors. During the years ended December 31, 2019, 2018, and 2017 the Company made contributions totaling $0.2 million, $0.1 million and $42,000, respectively, to the 401(k) Plan. The Company provides a pension contribution plan for its employees in the United Kingdom, pursuant to which the Company may match employees’ contributions each year (“U.K Plan”). During the years ended December 31, 2019, 2018 and 2017 the Company made contributions totaling $0.3 million, $0.2 million and $0.2 million, respectively, to the U.K. Plan.

Related party transactions	12 Months Ended
Related party transactions	Dec. 31, 2019
Related party transactions
Related party transactions	15. Related party transactions The Company has entered into Founder Royalty Agreements with its founders and initial investors (Note 12). No royalties have been earned or paid under the Founder Royalty Agreements to date. The Chairman of the Company’s Board of Directors is associated with Stone Sunny Isles Inc., which provided consultancy services to the Company totaling $0.1 million during the year ended December 31, 2019. The former Chairman of the Company’s Board of Directors is associated with 10X Capital Inc., which provided consultancy services to the Company totaling $50,000, $0.2 million, and $0.1 million during the years ended December 31, 2019, 2018 and 2017, respectively.

Geographic information

12 Months Ended

Dec. 31, 2019

Geographic information

Geographic information

16. Geographic information

The Company operates in two geographic regions: the United States and the United Kingdom. Information about the Company’s long‑lived assets held in different geographic regions is presented in the table below (in thousands):


	December 31,
	2019		2018
United States	$	2,017	$	498
United Kingdom		2,331		1,320
	$	4,348	$	1,818

The Company’s collaboration revenues are attributed to the operations of the Company in the United Kingdom.

Selected Quarterly Financial Data (Unaudited)

12 Months Ended

Dec. 31, 2019

Selected Quarterly Financial Data (Unaudited)

Selected Quarterly Financial Data (Unaudited)

17. Selected Quarterly Financial Data (Unaudited)

The following tables contain selected quarterly financial information for 2019 and 2018. The Company believes the following information includes all recurring adjustments necessary for a fair statement of such information (in thousands, except share and per share data):


	Three Months Ended
	December 31,		September 30,		June 30,		March 31,
	2019		2019		2019		2019
Statements of Operations Data:
Collaboration revenues	$	5,281	$	614	$	1,522	$	6,384
Total operating expenses		10,045		10,867		9,510		9,678
Total other income (expense), net		220		440		(2,094)		(3,129)
Net loss before income tax provision		(4,544)		(9,813)		(10,082)		(6,423)
(Benefit from) provision for income taxes		(138)		(331)		135		80
Net loss	$	(4,406)	$	(9,482)	$	(10,217)	$	(6,503)
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(0.25)	$	(0.53)	$	(1.40)	$	(7.80)
Weighted average ordinary shares outstanding, basic and diluted		17,926,165		17,900,978		7,298,139		834,043

	Three Months Ended
	December 31,		September 30,		June 30,		March 31,
	2018		2018		2018		2018
Statements of Operations Data:
Collaboration revenues	$	1,057	$	1,610	$	1,661	$	2,808
Total operating expenses		8,599		7,967		6,619		5,697
Total other expense, net		901		(1,335)		(21)		(41)
Net loss before income tax provision		(6,641)		(7,692)		(4,979)		(2,930)
Benefit from income taxes		—		—		—		(396)
Net loss	$	(6,641)	$	(7,692)	$	(4,979)	$	(2,534)
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(13.19)	$	(17.73)	$	(11.85)	$	(6.38)
Weighted average ordinary shares outstanding, basic and diluted		503,309		433,795		420,063		397,483

Subsequent events	12 Months Ended
Subsequent events	Dec. 31, 2019
Subsequent events
Subsequent events	18. Subsequent events On February 21, 2020, the Company entered into a Discovery Collaboration and License Agreement (the “Genentech Collaboration Agreement”) with Genentech, a member of the Roche Group. The collaboration is focused on the discovery and development of Bicycle peptides directed to biological targets selected by Genentech and aimed at developing up to four potential development candidates against multiple immuno-oncology targets suitable for Genentech to advance into further development and commercialization. Bicycle will be responsible for discovery and lead optimization of such Bicycle peptides through specified phases of the collaboration, and following drug candidate selection Genentech will be responsible for all future research and development. The initial discovery and optimization activities will focus on two immuno-oncology targets, potentially with additional targeting elements, and Genentech has the option to nominate up to two additional immuno-oncology targets, potentially with additional targeting elements, to be the subject of additional collaboration programs during a specified period following completion of certain activities under an agreed research plan, in which case Genentech will pay to the Company an expansion fee of $10.0 million per additional collaboration program. Genentech has the right, under certain limited circumstances, to select an alternative target to be the subject of a collaboration program, in some cases subject to payment of an additional target selection fee. Under the Genentech Collaboration Agreement, Genentech will make an upfront payment to the Company of $30.0 million. The Company will perform research activities for each target under the collaboration, under a mutually agreed upon research plan through specified collaboration phases, under the oversight of a joint research committee. For each collaboration program, Genentech may elect, at its sole discretion, to progress development candidates into further preclinical development and obtain exclusive worldwide development and commercialization rights for compounds directed to the target of such collaboration program in exchange for success-based milestone payments totaling $10-12 million per collaboration program. On a collaboration program-by-collaboration program basis, if Genentech elects to obtain exclusive development and commercialization rights and pays the applicable success-based milestone payments, Genentech will be required to make milestone payments to the Company upon the achievement of specified development, regulatory, and initial commercialization milestones for products arising from each collaboration program, totaling up to $200.0 million. In addition, the Company is also eligible to receive up to $200.0 million in sales milestone payments on a product-by-product basis. In addition, to the extent any of the product candidates covered by the licenses conveyed to Genentech are commercialized, the Company would be entitled to receive tiered royalty payments on net sales at percentages ranging from the mid-single to low double-digits, subject to certain standard reductions and offsets. Royalties will be payable, on a product-by-product and country-by-country basis, until the later of the expiration of specified licensed patents covering such product in such country, or ten years from first commercial sale of such product in such country. Either party may terminate the Genentech Collaboration Agreement for the uncured material breach of the other party or in the case of insolvency. Genentech may terminate the Genentech Collaboration Agreement for convenience on specified notice periods depending on the development stage of the applicable program, either in its entirety or on a program-by- program basis or major market-by-major market basis.

Summary of Significant Accounting Policies (Policies)

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies

Use of Estimates

Use of estimates

Foreign currency and currency translation

Concentrations of credit risk and of significant suppliers

Cash and cash equivalents

Accounts receivable

Deferred offering costs

Property and equipment


		Estimated Useful Life
Laboratory equipment		3 to 5 years
Leasehold improvements		Lesser of lease term or useful life
Computer equipment		3 years
Furniture and office equipment		5 years

Impairment of long‑lived assets

Fair value measurements

Level 1 — Quoted prices in active markets for identical assets or liabilities.

Warrant liability

Segment and geographic information

The Company operates in two geographic regions: the United Kingdom and the United States.

Leases

Revenue recognition

For a complete discussion of accounting for collaboration revenues, see Note 10, “Significant Agreements”

Government grants

Research and development costs

Research and manufacturing contract costs and accruals

Research and development incentives and receivable

Patent costs

Share‑based compensation

Recently adopted accounting pronouncements

Recently Issued Accounting Pronouncements

Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies

Schedule of estimated useful lives of property and equipment


		Estimated Useful Life
Laboratory equipment		3 to 5 years
Leasehold improvements		Lesser of lease term or useful life
Computer equipment		3 years
Furniture and office equipment		5 years

Fair value of financial assets and liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Fair value of financial assets and liabilities

Schedule of financial assets and liabilities measured at fair value on a recurring basis

The following tables present information about the Company’s financial assets and liabilities measured at fair value on a recurring basis (in thousands):


	Fair Value Measurement
	as of December 31, 2018 using:
	Level 1		Level 2		Level 3		Total
Liabilities:
Warrant liability	$	—	$	—	$	4,804	$	4,804
	$	—	$	—	$	4,804	$	4,804

Property and equipment, net (Tables)

12 Months Ended

Dec. 31, 2019

Property and equipment, net

Schedule of property and equipment, net

Property and equipment, net consisted of the following (in thousands):


	December 31,
	2019		2018
Laboratory equipment	$	4,326	$	3,356
Leasehold improvements		300		75
Computer equipment and software		229		221
Furniture and office equipment		120		99
		4,975		3,751
Less: Accumulated depreciation and amortization		(2,683)		(1,933)
	$	2,292	$	1,818

Accrued expenses and other current liabilities (Tables)

12 Months Ended

Dec. 31, 2019

Accrued expenses and other current liabilities

Schedule of accrued expenses and other current liabilities


	December 31,
	2019		2018
Accrued employee compensation and benefits	$	2,514	$	1,610
Accrued external research and development expenses		2,055		3,814
Income taxes payable		1		15
Accrued professional fees		867		1,494
Current portion of operating lease liabilities		640		—
Other		67		99
	$	6,144	$	7,032

Warrant liability (Tables)

12 Months Ended

Dec. 31, 2019

Warrant liability

Summary of roll-forward of the fair values of the Company’s warrant liability

The following table provides a roll-forward of the fair values of the Company’s warrant liability for which fair value was determined by Level 3 inputs (in thousands):


	Warrant
	Liability
Fair value at December 31, 2018	$	4,804
Change in fair value of warrant liability recorded as other expense		5,381
Conversion of warrant liability to equity upon closing of IPO and exercise of warrants		(10,021)
Impact of exchange rates on translation of warrant liability to USD included in accumulated other comprehensive income (loss)		(164)
Fair value at December 31, 2019	$	—

Warrants

Warrant liability

Summary of unobservable inputs to the fair value measurement of the warrant liability


		Remeasurement upon closing
	of the IPO on May 28, 2019						December 31, 2018
	Series A			Series B1			Series A			Series B1
	Warrants			Warrants			Warrants			Warrants (1)
Risk-free rate		2.2	%		2.1	%		2.6	%		2.5	%
Expected dividend yield		—	%		—	%		—	%		—	%
Expected term (years)		8.0			5.8			8.4			6.25
Expected volatility		74.7	%		78.2	%		75.4	%		79.6	%
Exercise price	£	0.01		£	0.01		£	0.01		£	0.01
Fair value of preferred shares or ordinary shares underlying the warrant	$	12.28		$	12.28		$	8.61		$	4.15

⁽¹⁾

Share-based compensation (Tables)

12 Months Ended

Dec. 31, 2019

Share-based compensation

Schedule of share based compensation expense

The Company recorded share‑based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
Research and development expenses	$	1,286	$	513	$	241
General and administrative expenses		1,797		510		274
	$	3,083	$	1,023	$	515

Schedule of share option activity


				Weighted
		Weighted		Average	Aggregate
	Number of	Average		Contractual	Intrinsic
	Shares	Exercise Price		Term	Value
				(in years)	(in thousands)
Outstanding as of December 31, 2018	863,712	$	1.01	8.75	$	3,292
Granted	2,134,538		12.01	—		—
Exercised	(85,839)		1.67	—		—
Forfeited	(278,065)		4.21	—		—
Outstanding as of December 31, 2019	2,634,346	$	9.57	9.04	$	6,107
Vested and expected to vest as of December 31, 2019	2,634,346	$	9.57	9.04	$	6,107
Options exercisable as of December 31, 2019	647,901	$	6.81	8.49	$	2,868

Schedule of assumptions used to determine the fair value of share options granted




	Year Ended
	December 31,
	2019		2018		2017
Risk-free interest rate	2.1	%	2.7	%	2.0	%
Expected volatility	77.9	%	78.6	%	79.7	%
Expected dividend yield	—		—		—
Expected term (in years)	5.86		6.07		6.07

Schedule of restricted ordinary share award activity


		Weighted Average
		Grant-Date
	Shares	Fair Value
Unvested restricted ordinary shares as of December 31, 2018	83,947	$	1.93
Issued	—		—
Forfeited	—		—
Vested	(83,947)		1.93
Unvested restricted ordinary shares as of December 31, 2019	—	$	—

Significant Agreements (Tables)

12 Months Ended

Dec. 31, 2019

Significant agreements.

Summary of revenue recognized from collaboration arrangements

The following table summarizes the revenue recognized in the Company’s consolidated statements of operations and comprehensive loss from these arrangements (in thousands):



	Year Ended
	December 31,
	2019		2018		2017
Collaboration revenues
AstraZeneca	$	1,683	$	1,386	$	890
Sanofi		10,724		4,007		355
Oxurion		—		1,743		815
Dementia Discovery Fund		394		—		—
Material transfer agreement		1,000		—		—
Total collaboration revenues	$	13,801	$	7,136	$	2,060

Summary of changes in the balances of the Company’s contract assets and liabilities


	Balance at						Impact of		Balance at
	Beginning of						Exchange		End of
	Period		Additions		Deductions		Rates		Period
Period ended December 31, 2019
Contract assets	$	—	$	149	$	(149)	$	—	$	—
Contract liabilities:
Deferred revenue
AstraZeneca collaboration deferred revenue		4,727		58		(35)		163		4,913
Sanofi collaboration deferred revenue		9,908		—		(9,984)		76		—
DDF collaboration deferred revenue		—		1,114		(394)		24		744
Total deferred revenue	$	14,635	$	1,172	$	(10,413)	$	263	$	5,657

The following table presents changes in the balances of the Company’s contract assets and liabilities (in thousands):


	Balance at						Impact of		Balance at
	Beginning of						Exchange		End of
	Year		Additions		Deductions		Rates		Period
Period ended December 31, 2018
Contract assets	$	—	$	91	$	(91)	$	—	$	—
Contract liabilities:
Deferred revenue
AstraZeneca collaboration deferred revenue		—		5,350		(466)		(157)		4,727
Sanofi collaboration deferred revenue		14,467		—		(4,006)		(553)		9,908
Total deferred revenue	$	14,467	$	5,350	$	(4,472)	$	(710)	$	14,635

Summary of recognition of revenues as a result of changes in contract asset and contract liability balances


	Year Ended
	December 31,
	2019		2018		2017
Revenue recognized in the period from:
Revenue recognized based on proportional performance	$	(429)	$	(4,472)	$	(355)
Revenue recognized based on expiration of material rights		(9,984)		—		—
Total	$	(10,413)	$	(4,472)	$	(355)

AstraZeneca

Significant agreements.

Summary of allocation of transaction price to separate performance obligations

Based on the relative standalone selling price, the allocation of the transaction price to the separate performance obligations is as follows (in thousands):


	Allocation of
Performance Obligations	Transaction Price
Target Three Research License and Related Services	$	650
Target 3 Material Right		1,504
Target 4 Material Right		1,204
Target 5 Material Right		1,165
Target 6 Material Right		1,127
	$	5,650

Sanofi

Significant agreements.

Summary of allocation of transaction price to separate performance obligations

Based on the relative standalone selling price, the allocation of the transaction price to the separate performance obligations was as follows (in thousands):


	Allocation of
Performance Obligations	Transaction Price
Sickle Cell Research License and Related Services	$	1,405
Hemophilia Research License and Related Services		2,811
Sickle Cell License Option Material Right		5,286
Hemophilia License Option Material Right		4,698
	$	14,200

Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Taxes

Schedule of components of net loss before tax provision from income taxes

The components of net loss before tax provision from income taxes are as follows (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
United Kingdom	$	(31,906)	$	(22,229)	$	(16,319)
United States		1,044		(13)		37
Total	$	(30,862)	$	(22,242)	$	(16,282)

Schedule of components of the benefit for income taxes

The components of the benefit for income taxes are as follows (in thousands):


	Year Ended
	December 31,
	2019		2018		2017
Current income tax provision (benefit)
Federal	$	49	$	(25)	$	75
State		61		7		10
Total current income tax provision (benefit)		110		(18)		85
Deferred income tax (benefit) provision
Federal		(295)		(167)		(58)
State		(69)		(211)		(50)
Total deferred income tax (benefit)		(364)		(378)		(108)
Total benefit from income taxes	$	(254)	$	(396)	$	(23)

Schedule of reconciliation of the provision (benefit) for income taxes


	Year Ended
	December 31,
	2019		2018		2017
Benefit for income taxes at statutory rate	19.0	%	19	%	19	%
(Decreases) increases resulting from:
Federal tax credits	1.3	%	1.1	%	0.4	%
Change in valuation allowance	(8.0)	%	(7.2)	%	(9.4)	%
Net losses surrendered for research credit	(5.3)	%	(3.7)	%	(6.7)	%
Preferred share warrants	(3.3)	%	(0.6)	%	(1.1)	%
Other	(2.9)	%	(6.8)	%	(2.1)	%
Effective income tax rate	0.8	%	1.8	%	0.1	%

Schedule of significant components of the Company’s current and deferred tax assets

Significant components of the Company’s current and deferred tax assets at December 31, 2019 and 2018, were as follows (in thousands):


	Year Ended
	December 31,
	2019		2018
Deferred tax assets:
Operating loss carryforwards	$	7,082	$	4,953
Research credit carryforwards		434		197
Operating lease liability		439		—
Accrued expenses and other		1,779		1,149
Total deferred tax assets		9,734		6,299
Deferred tax liabilities:
Operating lease right-of-use asset		(422)		—
Depreciation & amortization		(326)		(163)
Total deferred tax liabilities		(748)		(163)
Valuation allowance		(8,104)		(5,621)
Net deferred tax assets	$	882	$	515

Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2019

Commitments and Contingencies

Schedule of future minimum lease payments due under operating leases

The future minimum lease payments due under the Company’s operating leases as of December 31, 2018 under ASC 840 were as follows (in thousands):


Year Ending December 31,
2019	$	888
2020		901
2021		915
2022		483
2023		—
	$	3,187

Schedule of components of lease expense


	December 31,
	2019
Operating lease cost	$	900
Variable lease cost		390
Total lease cost	$	1,290
Weighted‑average remaining operating lease term (years)		2.6
Weighted‑average discount rate		8.52	%

Schedule of maturities of operating leases

Future minimum lease payments under non-cancelable operating leases under ASC 842 as of December 31, 2019 are as follows (in thousands):


Year Ending December 31,
2020	$	879
2021		777
2022		443
2023		—
2024		—
Present value adjustment		(208)
Total lease liabilities	$	1,891
Less: current lease liabilities		(640)
Long term lease liabilities	$	1,251

Net loss per share (Tables)

12 Months Ended

Dec. 31, 2019

Net loss per share

Schedule of basic and diluted net loss attributable to ordinary shareholders

Basic and diluted net loss per share attributable to ordinary shareholders was calculated as follows (in thousands, except share and per share amounts):


	Year Ended
	December 31,
	2019		2018		2017
Numerator:
Net loss attributable to ordinary shareholders	$	(30,608)	$	(21,846)	$	(16,259)
Denominator:
Weighted average ordinary shares outstanding, basic and diluted		11,045,370		438,862		333,125
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(2.77)	$	(49.78)	$	(48.81)

Schedule of antidilutive securities excluded from computation of net loss per share attributable to ordinary shareholders


	Year Ended
	December 31,
	2019	2018	2017
Convertible preferred shares (as converted to ordinary shares)	—	11,532,659	9,641,740
Warrants to subscribe for convertible preferred shares (as adjusted to reflect the impact of the share capital reorganization and issuance of bonus shares (Note 1))(1)(2)	92,885	1,347,953	1,347,953
Restricted ordinary shares	—	83,947	162,466
Options to purchase ordinary shares	2,634,346	863,712	964,538
	2,727,231	13,828,271	12,116,697

⁽¹⁾

⁽²⁾

At December 31, 2019 65,000 warrants are outstanding which are exercisable into 92,885 ordinary shares (Note 6).

Geographic information (Tables)

12 Months Ended

Dec. 31, 2019

Geographic information

Schedule of long-lived assets, including operating lease right-of-use assets, held in different geographic regions

Information about the Company’s long‑lived assets held in different geographic regions is presented in the table below (in thousands):


	December 31,
	2019		2018
United States	$	2,017	$	498
United Kingdom		2,331		1,320
	$	4,348	$	1,818

Selected Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Selected Quarterly Financial Data (Unaudited)

Schedule of selected quarterly financial information

The Company believes the following information includes all recurring adjustments necessary for a fair statement of such information (in thousands, except share and per share data):


	Three Months Ended
	December 31,		September 30,		June 30,		March 31,
	2019		2019		2019		2019
Statements of Operations Data:
Collaboration revenues	$	5,281	$	614	$	1,522	$	6,384
Total operating expenses		10,045		10,867		9,510		9,678
Total other income (expense), net		220		440		(2,094)		(3,129)
Net loss before income tax provision		(4,544)		(9,813)		(10,082)		(6,423)
(Benefit from) provision for income taxes		(138)		(331)		135		80
Net loss	$	(4,406)	$	(9,482)	$	(10,217)	$	(6,503)
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(0.25)	$	(0.53)	$	(1.40)	$	(7.80)
Weighted average ordinary shares outstanding, basic and diluted		17,926,165		17,900,978		7,298,139		834,043

	Three Months Ended
	December 31,		September 30,		June 30,		March 31,
	2018		2018		2018		2018
Statements of Operations Data:
Collaboration revenues	$	1,057	$	1,610	$	1,661	$	2,808
Total operating expenses		8,599		7,967		6,619		5,697
Total other expense, net		901		(1,335)		(21)		(41)
Net loss before income tax provision		(6,641)		(7,692)		(4,979)		(2,930)
Benefit from income taxes		—		—		—		(396)
Net loss	$	(6,641)	$	(7,692)	$	(4,979)	$	(2,534)
Net loss per share attributable to ordinary shareholders, basic and diluted	$	(13.19)	$	(17.73)	$	(11.85)	$	(6.38)
Weighted average ordinary shares outstanding, basic and diluted		503,309		433,795		420,063		397,483

Nature of the business and basis of presentation - Share capital reorganization and share split (Details)	1 Months Ended
	May 31, 2019
Nature of business and basis of presentation
Stock split of common stock for bonus shares	1.429

Nature of the business and basis of presentation - Initial public offering (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended	12 Months Ended
	May 28, 2019 $ / shares shares	Jun. 30, 2019 shares	Jun. 30, 2019 shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Share capital reorganization and share split
Offering expenses \| $				$ 8,500	$ 327	$ 587
Ordinary Shares
Share capital reorganization and share split
Shares issued (in shares)				4,637,666
Conversion of convertible preferred shares to ordinary shares (in shares)			11,647,529	11,647,529
IPO
Share capital reorganization and share split
Shares issued (in shares)	4,333,333
Share issue price \| $ / shares	$ 14.00
Proceeds from IPO, net \| $				$ 56,400
Underwriting discounts and commissions \| $				4,500
Offering expenses \| $				$ 4,000
IPO \| Ordinary Shares
Share capital reorganization and share split
Conversion of convertible preferred shares to ordinary shares (in shares)	11,647,529
Conversion ratio	0.6997
Over allotment option
Share capital reorganization and share split
Shares issued (in shares)		304,333

Nature of the business and basis of presentation- Liquidity (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Nature of business and basis of presentation
Net loss	$ 4,406	$ 9,482	$ 10,217	$ 6,503	$ 6,641	$ 7,692	$ 4,979	$ 2,534	$ 30,608	$ 21,846	$ 16,259
Accumulated deficit	$ 100,550				$ 69,942				$ 100,550	$ 69,942

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Summary of Significant Accounting Policies - Foreign currency and currency translation (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of Significant Accounting Policies
Foreign exchange gains (loss)	$ 0.9	$ 0.3	$ (0.6)

Summary of Significant Accounting Policies - Cash and cash equivalents (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Summary of Significant Accounting Policies
Cash and Cash Equivalents, at Carrying Value	$ 0	$ 0

Summary of Significant Accounting Policies - Property and equipment (Details)	12 Months Ended
	Dec. 31, 2019
Computer equipment and software
Property and equipment
Estimated Useful Life	3 years
Furniture and office equipment
Property and equipment
Estimated Useful Life	5 years
Minimum \| Laboratory equipment
Property and equipment
Estimated Useful Life	3 years
Maximum \| Laboratory equipment
Property and equipment
Estimated Useful Life	5 years

Summary of significant accounting policies - Government grants (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Summary of Significant Accounting Policies
Reduction of research and development	$ 0.6
Proceeds from government grants		$ 0.0	$ 0.0

Summary of Significant Accounting Policies - Research and development incentives and receivable (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Research and development incentives and receivable
Maximum percentage of surrenderable losses	14.50%
Reduction of research and development	$ 6.7	$ 5.9	$ 2.9

Summary of Significant Accounting Policies - Share based compensation (Details)	12 Months Ended
	Dec. 31, 2019
Summary of Significant Accounting Policies
Expected dividend yield	0.00%

Summary of Significant Accounting Policies - Recently adopted accounting pronouncements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019
Recently adopted accounting pronouncements
Right-of-use assets	$ 2,056
ASU 2016-02, Leases (Topic 842)
Recently adopted accounting pronouncements
Right-of-use assets		$ 2,700
Lease liabilities		$ 2,600
ASU 2018-15
Recently adopted accounting pronouncements
Implementation cost capitalized in cloud computing arrangement, service contract	$ 100

Fair value of financial assets and liabilities - Financial assets and liabilities measured at fair value (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Fair value of financial assets and liabilities
Warrant liability		$ 4,804
Warrant liability
Fair value of financial assets and liabilities
Warrant liability	$ 0	4,804
Level 3
Fair value of financial assets and liabilities
Warrant liability		4,804
Level 3 \| Warrant liability
Fair value of financial assets and liabilities
Warrant liability		$ 4,804

Fair value of financial assets and liabilities - Transfers between levels (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair value of financial assets and liabilities
Level 1 to Level 2 transfers, liabilities	$ 0	$ 0
Level 2 to Level 1 transfers, liabilities	0	0
Transfers into level 3, liabilities	0	0
Transfers out of level 3, liabilities	$ 0	$ 0

Property and equipment, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property and equipment, net
Property and equipment, gross	$ 4,975	$ 3,751
Less: Accumulated depreciation and amortization	(2,683)	(1,933)
Property and equipment, net	2,292	1,818
Depreciation expense	1,000	700	$ 300
Laboratory equipment
Property and equipment, net
Property and equipment, gross	4,326	3,356
Leasehold improvements
Property and equipment, net
Property and equipment, gross	300	75
Computer equipment and software
Property and equipment, net
Property and equipment, gross	229	221
Furniture and office equipment
Property and equipment, net
Property and equipment, gross	$ 120	$ 99

Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Accrued expenses and other current liabilities
Accrued employee compensation and benefits	$ 2,514	$ 1,610
Accrued external research and development expenses	2,055	3,814
Income taxes payable	1	15
Accrued professional fees	867	1,494
Current portion of operating lease liabilities	$ 640
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	us-gaap:AccruedLiabilitiesCurrent us-gaap:OperatingLeaseLiabilityNoncurrent
Other	$ 67	99
Accrued expenses and other current liabilities	$ 6,144	$ 7,032

Convertible preferred shares (Details) $ / shares in Units, $ in Millions						1 Months Ended	3 Months Ended	12 Months Ended
	May 28, 2019 $ / shares shares	Jan. 03, 2019 USD ($) shares	Dec. 20, 2018 USD ($) shares	Oct. 27, 2017 USD ($) shares	May 26, 2017 USD ($) shares	May 31, 2019	Jun. 30, 2019 shares	Dec. 31, 2019 shares	Jan. 03, 2019 £ / shares	Dec. 20, 2018 £ / shares	Oct. 27, 2017 £ / shares	May 26, 2017 £ / shares
Convertible preferred shares
Stock split ratio						1.429
IPO
Convertible preferred shares
Number of shares issued (in shares)	4,333,333
Share issue price \| $ / shares	$ 14.00
Ordinary Shares
Convertible preferred shares
Number of shares issued (in shares)								4,637,666
Conversion of convertible preferred shares to ordinary shares (in shares)							11,647,529	11,647,529
Ordinary Shares \| IPO
Convertible preferred shares
Conversion of convertible preferred shares to ordinary shares (in shares)	11,647,529
Conversion ratio	0.6997
Series B1 Convertible Preferred Shares
Convertible preferred shares
Number of shares issued (in shares)				384,615	3,562,583
Share issue price \| £ / shares											£ 13	£ 11.2278
Gross proceeds from issues of shares \| $				$ 6.6	$ 51.9
Numbers of warrants issued			194,911	743,287
Number of warrants surrendered			194,911
Series B2 Convertible Preferred Shares
Convertible preferred shares
Number of shares issued (in shares)		80,385	1,323,248
Share issue price \| £ / shares									£ 15.55	£ 15.55
Gross proceeds from issues of shares \| $		$ 1.6	$ 26.1

Warrant liability - Warrants information (Details) $ in Thousands						9 Months Ended	12 Months Ended
	May 28, 2019 shares	Dec. 20, 2018 shares	Oct. 27, 2017 £ / shares shares	May 26, 2017 £ / shares shares	Mar. 07, 2017	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 £ / shares shares
Warrants information
Exercise price of warrants \| £ / shares										£ 0.01
Number of shares issued for warrant exercise	171,480
Remaining warrants exercisable	80,000									65,000
Number of shares into which remaining warrants is exercisable	114,320									92,885
Change in fair value of preferred stock warrant liability \| $						$ 5,381	$ 5,381	$ 665	$ 119
Other expenses
Warrants information
Change in fair value of preferred stock warrant liability \| $							$ 100
Expected dividend yield
Warrants information
Fair value measurement of the warrant liability										0
Series A Preferred Shares
Warrants information
Numbers of warrants issued				200,000
Exercise price of warrants \| £ / shares				£ 0.01
Warrants exercisable term				10 years
Warrants expiration term following an IPO or exit				12 months
Number of warrants exercised	120,000
Series B1 Preferred Shares
Warrants information
Numbers of warrants issued		194,911	115,384	627,903
Exercise price of warrants \| £ / shares			£ 0.01	£ 0.01
Number of shares issued for warrant exercise	531,077
Number of shares issued (in shares)			384,615	3,562,583
Share issue price \| £ / shares				£ 11.2278
Number of warrants surrendered		194,911
Percentage of warrants exercisable in conjunction with the IPO					50.00%
Percentage of warrants to expire in conjunction with the IPO					50.00%

Warrant liability - Roll-forward of fair values of warrant liability (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Roll-forward of the fair values of the Company’s warrant liability
Fair value at the beginning	$ 4,804	$ 4,804
Change in fair value of warrant liability	5,381	5,381	$ 665	$ 119
Conversion of warrant liability to equity upon closing of IPO and exercise of warrants	(10,021)	$ (10,027)
Impact of exchange rates on translation of warrant liability to USD included in accumulated other comprehensive income (loss)	$ (164)
Fair value at the end			$ 4,804

Warrant liability - Unobservable inputs to the fair value measurement of the warrant liability (Details)	Dec. 31, 2019 £ / shares	May 28, 2019 $ / shares £ / shares	Dec. 31, 2018 $ / shares £ / shares
Unobservable inputs to the fair value measurement of the warrant liability
Exercise price of warrants	£ 0.01
Risk free rate \| Series A Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		2.2	2.6
Risk free rate \| Series B1 Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		2.1	2.5
Expected dividend yield
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability	0
Expected term (years) \| Series A Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		8.0	8.4
Expected term (years) \| Series B1 Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		5.8	6.25
Expected volatility \| Series A Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		74.7	75.4
Expected volatility \| Series B1 Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		78.2	79.6
Exercise price \| Series A Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		0.01	0.01
Exercise price \| Series B1 Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability		0.01	0.01
Fair value of preferred shares or ordinary shares underlying the warrant \| Series A Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability \| $ / shares		12.28	8.61
Fair value of preferred shares or ordinary shares underlying the warrant \| Series B1 Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability \| $ / shares		12.28	4.15
Probability that the warrants will not be exercisable prior to the IPO \| Series B1 Warrants
Unobservable inputs to the fair value measurement of the warrant liability
Fair value measurement of the warrant liability			50

Ordinary shares (Details)	12 Months Ended
Ordinary shares (Details)	Dec. 31, 2019 Vote £ / shares shares	Dec. 31, 2018 £ / shares shares
Ordinary shares
Vote per ordinary share \| Vote	1
Ordinary shares, shares authorized \| shares	31,995,653	15,452,420
Ordinary shares, nominal value \| £ / shares	£ 0.01	£ 0.01

Share-based compensation (Details)	1 Months Ended	12 Months Ended
Share-based compensation (Details)	May 31, 2019 shares	Dec. 31, 2019 $ / shares shares	Dec. 31, 2018 $ / shares	Dec. 31, 2017	Jan. 01, 2020 shares	May 27, 2019 £ / shares
Stock option
Share-based compensation.
Exercise price \| $ / shares		$ 9.57	$ 1.01
Employee Share Purchase Plan
Share-based compensation.
Number of ordinary shares reserved for issuance	215,000
Percentage of ordinary shares at a price per share equal to the fair market value on offering date or purchase date	85.00%
2017 Plan
Share-based compensation.
Number of shares reserved for issuance					719,748
2019 Plan
Share-based compensation.
Number of ordinary shares reserved for issuance	2,470,583
2019 Plan \| Stock option
Share-based compensation.
Percentage of annual increase in reserves on total number of ordinary shares outstanding	4.00%
Number of shares available for issuance		872,646
Contractual life	10 years
2019 Plan \| Stock option \| First anniversary
Share-based compensation.
Vesting Percentage	25.00%
2019 Plan \| Stock option \| 36 equal monthly installments
Share-based compensation.
Number of equal monthly installments for vesting remaining awards	36 months
2019 Plan \| Minimum \| Stock option
Share-based compensation.
Vesting period	3 years
2019 Plan \| Maximum \| Stock option
Share-based compensation.
Vesting period	4 years
Pre-IPO Share Options and restricted shares \| Stock option
Share-based compensation.
Contractual life		10 years
Vesting period		4 years
Pre-IPO Share Options and restricted shares \| Stock option \| First anniversary
Share-based compensation.
Vesting Percentage		25.00%
Pre-IPO Share Options and restricted shares \| Stock option \| 36 equal monthly installments
Share-based compensation.
Number of equal monthly installments for vesting remaining awards		36 months
Pre-IPO Share Options and restricted shares \| Stock option \| United Kingdom
Share-based compensation.
Exercise price \| £ / shares						£ 0.01
Pre-IPO Share Options and restricted shares \| Performance based option \| First anniversary
Share-based compensation.
Vesting Percentage			20.00%	20.00%
Pre-IPO Share Options and restricted shares \| Performance based option \| 36 equal monthly installments
Share-based compensation.
Vesting Percentage			60.00%	60.00%
Number of equal monthly installments for vesting remaining awards			36 months	36 months
Pre-IPO Share Options and restricted shares \| Performance based option \| Earlier of the fourth anniversary
Share-based compensation.
Vesting Percentage			20.00%	20.00%

Share-based compensation - Share based compensation expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share based compensation expense
Total share-based compensation expense	$ 3,083	$ 1,023	$ 515
Research and development expenses
Share based compensation expense
Total share-based compensation expense	1,286	513	241
General and administrative expenses
Share based compensation expense
Total share-based compensation expense	$ 1,797	$ 510	$ 274

Share-based compensation - Share options (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Additional Information
Total share-based compensation expense	$ 3,083,000	$ 1,023,000	$ 515,000
Ordinary Shares
Number of Shares
Exercised	(85,839)	(9,361)	(4,300)
Stock option
Number of Shares
Outstanding number of shares at beginning	863,712
Granted	2,134,538
Exercised	(85,839)
Forfeited	(278,065)
Outstanding number of shares at end	2,634,346	863,712
Number of shares, vested and expected to vest	2,634,346
Number of shares, options exercisable	647,901
Weighted Average Exercise Price
Weighted average exercise price at beginning	$ 1.01
Granted	12.01
Exercised	1.67
Forfeited	4.21
Weighted average exercise price at ending	9.57	$ 1.01
Weighted average exercise price, vested and expected to vest	9.57
Weighted average exercise price, options exercisable	$ 6.81
Weighted Average Contractual Term
Weighted average contractual term, outstanding	9 years 15 days	8 years 9 months
Weighted average contractual term, vested and expected to vest	9 years 15 days
Weighted average contractual term ,options exercisable	8 years 5 months 27 days
Aggregate Intrinsic Value
Aggregate intrinsic value outstanding	$ 6,107,000	$ 3,292,000
Granted	$ 6.07	$ 3.73	$ 1.78
Exercised	$ 600,000	$ 23,000	$ 7,000
Aggregate intrinsic value, vested and expected to vest	6,107,000
Aggregate intrinsic value, options exercisable	$ 2,868,000
Additional Information
Granted	$ 6.07	$ 3.73	$ 1.78
Total share-based compensation expense	$ 2,700,000	$ 800,000	$ 400,000
Performance based option
Number of Shares
Granted	0	70,875	678,610
Additional Information
Total share-based compensation expense	$ 100,000	$ 700,000	$ 300,000
Performance based option \| Ordinary Shares \| First anniversary
Additional Information
Vesting Percentage		20.00%
Performance based option \| Ordinary Shares \| 36 equal monthly installments
Additional Information
Vesting Percentage		60.00%
Number of equal monthly installments for vesting remaining awards		36 months
Performance based option \| Ordinary Shares \| Earlier of the fourth anniversary
Additional Information
Vesting Percentage		20.00%

Share-based compensation - Assumptions used in the Black Scholes option pricing model to determine the fair value of share options (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based compensation.
Expected dividend yield	0.00%
Stock option \| Employees and directors
Share-based compensation.
Risk-free interest rate	2.10%	2.70%	2.00%
Expected volatility	77.90%	78.60%	79.70%
Expected term (in years)	5 years 10 months 10 days	6 years 26 days	6 years 26 days
Unrecognized compensation expense
Total unrecognized compensation expense related to the unvested employee and director	$ 10.6
Unrecognized compensation cost expected to be recognized over a weighted average period	2 years 6 months

Share-based compensation - Restricted shares (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 USD ($) $ / shares shares	Dec. 31, 2017 USD ($)	Dec. 31, 2018 GBP (£)
Restricted shares
Total share-based compensation expense	$ 3,083	$ 1,023	$ 515
Restricted ordinary shares
Share-based compensation.
Repurchase rights aggregate consideration \| £				£ 1
Number of shares
Unvested restricted ordinary shares at beginning \| shares	83,947
Vested \| shares	(83,947)
Unvested restricted ordinary shares at ending \| shares		83,947
Weighted Average Grant Date Fair Value
Weighted average grant date fair value unvested, Beginning Balance \| $ / shares	$ 1.93
Weighted average grant date fair value vested \| $ / shares	$ 1.93
Weighted average grant date fair value unvested, Ending Balance \| $ / shares		$ 1.93
Restricted shares
Incremental share based compensation expense	$ 200
Total share-based compensation expense	400	$ 200	100
Restricted ordinary shares \| Employees and directors
Restricted shares
Unrecognized compensation cost	0
Restricted ordinary shares \| Employee
Restricted shares
Fair value of employee restricted share awards vested	$ 700	$ 200	$ 100

Significant agreements - Collaboration revenues (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant agreements.
Collaboration revenues	$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808	$ 13,801	$ 7,136	$ 2,060
AstraZeneca
Significant agreements.
Collaboration revenues									1,683	1,386	890
Sanofi
Significant agreements.
Collaboration revenues									10,724	4,007	355
Oxurion
Significant agreements.
Collaboration revenues									0	1,743	$ 815
Dementia Discovery Fund
Significant agreements.
Collaboration revenues									394
Material transfer agreement
Significant agreements.
Collaboration revenues									$ 1,000	$ 0

Significant agreements - AstraZeneca Collaboration Agreement (Details) $ in Thousands		1 Months Ended			3 Months Ended								12 Months Ended
	May 31, 2019 employee	May 31, 2018 USD ($)	Aug. 31, 2017 USD ($)	Nov. 30, 2016 USD ($) employee item	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Oct. 31, 2017 USD ($)
Significant agreements.
Transaction price			$ 14,200
Collaboration revenues					$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808	$ 13,801	$ 7,136	$ 2,060
Deferred revenue					5,657				14,635				5,657	14,635	14,467
AstraZeneca
Significant agreements.
Biological Targets \| item				6
Term (in years)			3 years
Term, Bicycle Research Team (in years)				1 year
Term, AZ Research (in years)				2 years
Number of FTE \| employee				2
Collaboration revenues													1,683	1,386	890
Deferred revenue					4,913				4,727				4,913	4,727
AstraZeneca \| Target One
Significant agreements.
Transaction price				$ 600												$ 2,000
AstraZeneca \| Target Two
Significant agreements.
Transaction price				600
AstraZeneca \| Target Three Research License and Related Services
Significant agreements.
Collaboration revenues													1,500	400	0
AstraZeneca \| Development Milestone
Significant agreements.
Transaction price		$ 700
AstraZeneca \| Development Milestone \| Development milestone
Significant agreements.
Customer option payment				29,000
AstraZeneca \| Regulatory Milestone \| Regulatory milestone
Significant agreements.
Customer option payment				23,000
AstraZeneca \| Commercial milestone \| Commercial milestone
Significant agreements.
Customer option payment				$ 110,000
AstraZeneca \| Minimum
Significant agreements.
Term extension (in years)				12 months
AstraZeneca \| Maximum
Significant agreements.
Term extension (in years)				15 months
AstraZeneca \| 2016 Collaboration Agreement
Significant agreements.
Biological Targets \| item				2
Option fee for development and exploitation rights				$ 8,000
Transaction price				$ 1,200
Research term related to research license and related services				1 year
Deferred revenue									$ 8,000					8,000	0
AstraZeneca \| 2016 Collaboration Agreement \| Target One and Target Two Research License and Related Services
Significant agreements.
Collaboration revenues													200	$ 1,000	$ 900
AstraZeneca \| 2016 Collaboration Agreement \| Commercialization license per candidate
Significant agreements.
Customer option payment				$ 8,000
AstraZeneca \| May 2018 Option Exercise
Significant agreements.
Biological Targets \| item				4
Option fee for development and exploitation rights		5,000		$ 5,000
Number of FTE \| employee	2
Transaction price					5,650		$ 6,300						5,650
AstraZeneca \| May 2018 Option Exercise \| Target Three Research License and Related Services
Significant agreements.
Transaction price					650								650
AstraZeneca \| May 2018 Option Exercise \| Target 3 Material Right
Significant agreements.
Transaction price					1,504								1,504
AstraZeneca \| May 2018 Option Exercise \| Target 4 Material Right
Significant agreements.
Transaction price					1,204								1,204
AstraZeneca \| May 2018 Option Exercise \| Target 5 Material Right
Significant agreements.
Transaction price					1,165								1,165
AstraZeneca \| May 2018 Option Exercise \| Target 6 Material Right
Significant agreements.
Transaction price					$ 1,127								$ 1,127
AstraZeneca \| May 2018 Option Exercise \| Commercialization license per candidate
Significant agreements.
Customer option payment		$ 8,000

Significant agreements - Sanofi Collaboration Agreement (Details) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Aug. 31, 2017 USD ($) employee	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Significant agreements.
Transaction price	$ 14,200
Revenue recognized by non exercising of option										$ 9,984
Revenue from collaborative arrangement		$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808	13,801	$ 7,136	$ 2,060
Deferred revenue		5,657				14,635				5,657	14,635	14,467
Sickle Cell Research License and Related Services
Significant agreements.
Transaction price	1,405
Hemophilia Research License and Related Services
Significant agreements.
Transaction price	2,811
Sickle Cell License Option Material Right
Significant agreements.
Transaction price	5,286
Hemophilia License Option Material Right
Significant agreements.
Transaction price	4,698
Sanofi
Significant agreements.
Option fee payment to obtain the screening services	$ 5,000
Term of research program	3 years
Renewal period of Research	1 year
Upfront cash payment	$ 10,000
Non refundable payment for services during the BV Bicycle Research Term	$ 4,200
Threshold period of notice required for termination of agreement	30 days
Transaction price	$ 14,200	14,900								14,900
Revenue from collaborative arrangement										10,724	4,007	355
Deferred revenue		$ 0				$ 9,908				0	$ 9,908	$ 14,467
Sanofi \| Sickle Cell Research License and Related Services
Significant agreements.
Non refundable payment for services during the BV Bicycle Research Term	1,400
Revenue recognized by non exercising of option										5,300
Sanofi \| Hemophilia Research License and Related Services
Significant agreements.
Non refundable payment for services during the BV Bicycle Research Term	2,800
Sanofi \| Hemophilia License Option Material Right
Significant agreements.
Revenue recognized by non exercising of option										$ 4,700
Sanofi \| Program 3
Significant agreements.
Non refundable payment for services during the BV Bicycle Research Term	$ 1,400
Sanofi \| Minimum
Significant agreements.
Number of FTE \| employee	2
Sanofi \| Development milestone
Significant agreements.
Option fee payable in order to obtain worldwide development and exploitation rights	$ 5,000
Sanofi \| Development milestone \| Sickle Cell License Option Material Right
Significant agreements.
Potential milestone payments	47,500
Sanofi \| Development milestone \| Hemophilia License Option Material Right
Significant agreements.
Potential milestone payments	67,000
Sanofi \| Regulatory milestone
Significant agreements.
Potential milestone payments	104,000
Sanofi \| Commercial milestone
Significant agreements.
Potential milestone payments	55,000
Sanofi \| Commercialization license per candidate
Significant agreements.
Potential milestone payments	$ 5,000

Significant agreements - Oxurion Collaboration Agreement (Details) $ in Thousands, € in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)
Significant agreements.
Revenue from collaborative arrangement	$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808		$ 13,801	$ 7,136	$ 2,060
Deferred revenue					14,635						$ 14,635	14,467	$ 5,657
Oxurion
Significant agreements.
Threshold period of notice required for termination of agreement											90 days
Revenue from collaborative arrangement										0	$ 1,743	815
Deferred revenue					$ 0						0		$ 0
Oxurion \| Development milestone
Significant agreements.
Upfront cash payment \| €									€ 1.0
Potential milestone payments \| €									8.3
Revenue under contracts with customer from milestone payment \| €									1.8
Revenue from collaborative arrangement										$ 0	$ 1,200	$ 800
Oxurion \| Regulatory milestone
Significant agreements.
Potential milestone payments \| €									€ 16.5

Significant agreements - Dementia Discovery Fund Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	May 31, 2019	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 31, 2017
Significant agreements.
Transaction price													$ 14,200
Collaboration revenues		$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808	$ 13,801	$ 7,136	$ 2,060
Deferred revenue		5,657				$ 14,635				5,657	$ 14,635	$ 14,467
Dementia Discovery Fund
Significant agreements.
Upfront cash payment	$ 1,100
Potential milestone payments	$ 700
Threshold period for exercising option to establish a jointly-owned new company	90 days
Option to purchase ownership of new entity	34.00%
Threshold period of notice required for termination of agreement	60 days
Transaction price	$ 1,100
Collaboration revenues										394
Deferred revenue		$ 744								$ 744
Dementia Discovery Fund \| NewCo
Significant agreements.
Option to purchase ownership of new entity	66.00%
Threshold period in which Newco shall have the right to initiate a new research program	2 years
Dementia Discovery Fund \| NewCo \| Maximum
Significant agreements.
Total voting rights related to ownership interests	50.00%

Significant agreements - Jazz Pharmaceuticals (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended								12 Months Ended
	Oct. 31, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant agreements.
Collaboration revenues		$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808	$ 13,801	$ 7,136	$ 2,060
Material transfer agreement
Significant agreements.
Upfront cash payment	$ 1,000
Threshold period for receipt of revenue after receipt of the materials and related data package	30 days
Term (in years)	14 months
Threshold period of notice required for termination of agreement	45 days
Collaboration revenues										$ 1,000	$ 0

Significant agreements - Summary of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Contract assets
Additions	$ 149	$ 91
Deductions	(149)	(91)
Contract liabilities:
Balance at the beginning of year	14,635	14,467
Additions	1,172	5,350
Deductions	(10,413)	(4,472)
Impact of exchange rates	263	(710)
Balance at the end of year	5,657	14,635
AstraZeneca
Contract liabilities:
Balance at the beginning of year	4,727
Additions	58	5,350
Deductions	(35)	(466)
Impact of exchange rates	163	(157)
Balance at the end of year	4,913	4,727
Sanofi
Contract liabilities:
Balance at the beginning of year	9,908	14,467
Deductions	(9,984)	(4,006)
Impact of exchange rates	76	(553)
Balance at the end of year	0	$ 9,908
Dementia Discovery Fund
Contract liabilities:
Additions	1,114
Deductions	(394)
Impact of exchange rates	24
Balance at the end of year	$ 744

Significant agreements - Deferred revenue (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred revenue
Deferred revenue	$ 5,657	$ 14,635	$ 14,467
Sanofi
Deferred revenue
Deferred revenue	0	9,908	$ 14,467
AstraZeneca
Deferred revenue
Deferred revenue	4,913	$ 4,727
AstraZeneca \| Target 3, Target 4, Target 5 and Target 6 Material Rights
Deferred revenue
Deferred revenue	$ 4,900

Significant agreements - Revenue recognition due to changes in contract assets and liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant Agreements
Revenue recognized based on proportional performance	$ (429)	$ (4,472)	$ (355)
Revenue recognized based on expiration of material rights	(9,984)
Total	$ (10,413)	$ (4,472)	$ (355)

Significant agreements - Cancer Research UK (Details) - USD ($) $ in Millions		1 Months Ended
	Dec. 13, 2016	Dec. 31, 2019	Dec. 31, 2018
Research and development arrangement obligation to repay other parties
Contingent future milestones payments under research and development arrangement	$ 50.9	$ 60.3
Other long term liabilities
Research and development arrangement obligation to repay other parties
Liability from research and development		$ 2.0	$ 0.8
Commercialization license per candidate
Research and development arrangement obligation to repay other parties
Refunding the costs and expenses incurred in case of termination (as a percent)	50.00%
BT1718 \| Minimum
Research and development arrangement obligation to repay other parties
Tiered royalties (percentage)	70.00%
BT1718 \| Maximum
Research and development arrangement obligation to repay other parties
Tiered royalties (percentage)	90.00%
BT7401 \| Minimum
Research and development arrangement obligation to repay other parties
Tiered royalties (percentage)		55.00%
BT7401 \| Maximum
Research and development arrangement obligation to repay other parties
Tiered royalties (percentage)		80.00%

Income Taxes (Details) $ in Thousands, £ in Millions	3 Months Ended					12 Months Ended
Income Taxes (Details) $ in Thousands, £ in Millions	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 USD ($)
Income Taxes.
Benefit from income taxes	$ 138	$ 331	$ (135)	$ (80)	$ 396	$ 254	$ 396	$ 23
Increases recorded to income tax provision								2,500
U.K. operating loss carryforwards										$ 41,700
Federal and state net operating loss carryforwards										0
Amount subject to offset each year \| £									£ 5.0
Incremental percentage of U.K. taxable profits						50.00%
Research credit carryforwards							197			434
Uncertain tax positions							0			0
Interest and penalties accrued							$ 0	$ 0		0
Federal
Income Taxes.
Research credit carryforwards										300
State
Income Taxes.
Research credit carryforwards										$ 200

Income Taxes - Components of net loss before tax provision from income taxes (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
United Kingdom									$ (31,906)	$ (22,229)	$ (16,319)
United States									1,044	(13)	37
Net loss before income tax provision	$ (4,544)	$ (9,813)	$ (10,082)	$ (6,423)	$ (6,641)	$ (7,692)	$ (4,979)	$ (2,930)	$ (30,862)	$ (22,242)	$ (16,282)

Income Taxes - Components of benefit for income taxes (Details) - USD ($) $ in Thousands	3 Months Ended					12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current income tax provision (benefit)
Federal						$ 49	$ (25)	$ 75
State						61	7	10
Total current income tax provision (benefit)						110	(18)	85
Deferred income tax (benefit) provision
Federal						(295)	(167)	(58)
State						(69)	(211)	(50)
Total deferred income tax (benefit)						(364)	(378)	(108)
Total benefit from income taxes	$ (138)	$ (331)	$ 135	$ 80	$ (396)	$ (254)	$ (396)	$ (23)

Income Taxes - Reconciliation of provision (benefit) for income taxes (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Benefit for income taxes at statutory rate	19.00%	19.00%	19.00%
(Decreases) increases resulting from:
Federal tax credits	1.30%	1.10%	0.40%
Change in valuation allowance	(8.00%)	(7.20%)	(9.40%)
Net losses surrendered for research credit	(5.30%)	(3.70%)	(6.70%)
Preferred share warrants	(3.30%)	(0.60%)	(1.10%)
Other	(2.90%)	(6.80%)	(2.10%)
Effective income tax rate	0.80%	1.80%	0.10%

Income Taxes - Components of the company’s current and deferred tax assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Operating loss carryforwards	$ 7,082	$ 4,953
Research credit carryforwards	434	197
Operating lease liability	439
Accrued expenses and other	1,779	1,149
Total deferred tax assets	9,734	6,299
Deferred tax liabilities:
Operating lease right-of-use asset	(422)
Depreciation & amortization	(326)	(163)
Total deferred tax liabilities	(748)	(163)
Valuation allowance	(8,104)	(5,621)
Net deferred tax assets	$ 882	$ 515

Commitments and Contingencies - Leases, Tenancy agreement (Details) - Tenancy agreement for space in Building 260 Babraham Research Campus, Cambridge - USD ($) $ in Millions	Oct. 31, 2017	Sep. 30, 2015
Leases
Leases, term of contract		2 years
Annual rent	$ 0.2	$ 0.2

Commitments and Contingencies - Leases, Office and laboratory space in Cambridge and Lexington, Massachusetts (Details) - Office and laboratory space in Lexington, Massachusetts - USD ($)	1 Months Ended
	Sep. 30, 2017	Jan. 31, 2017
Leases
Security deposit	$ 200,000
Payment under the lease	$ 100,000	$ 19,500
Discounted percentage for present value of lease payments	9.00%

Commitments and Contingencies - Leases, Office and laboratory space in Building 900, Babraham Research Campus, Cambridge (Details) - Office and laboratory space in Building 900, Babraham Research Campus, Cambridge $ in Millions	Oct. 31, 2017 USD ($)
Leases
Annual rent	$ 0.5
Renewal term	5 years
Estimated service charges payable	$ 0.1
Security deposit	$ 0.6
Discounted percentage for present value of lease payments	7.75%

Commitments and Contingencies - Leases, Future minimum lease payments under operating leases and rent expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Commitments and Contingencies
Rent expense	$ 1,000	$ 500
Future minimum lease payments due under operating leases
2019	888
2020	901
2021	915
2022	483
Total	$ 3,187

Commitments and Contingencies - Leases, Components of lease expense (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Commitments and Contingencies
Operating lease cost	$ 900
Variable lease cost	390
Total lease cost	$ 1,290
Weighted-average remaining operating lease term (years)	2 years 7 months 6 days
Weighted-average discount rate	8.52%

Commitments and Contingencies - Leases, Maturities of operating leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019 USD ($)
Commitments and Contingencies
2020	$ 879
2021	777
2022	443
Present value adjustment	(208)
Total lease liabilities	1,891
Less: current lease liabilities	(640)
Long term lease liabilities	$ 1,251
Maximum days allowed for cancellation of contracts prior written notice	90 days

Commitments and Contingencies - Founder Royalty arrangements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 28, 2019	May 31, 2017
Founder Royalty arrangements
Number of shares into which remaining warrants is exercisable	92,885			114,320
Research and development	$ 25,540	$ 20,761	$ 11,866
Founders and initial investors \| Royalty Agreements
Founder Royalty arrangements
Period of royalty payments agreed under arrangement	10 years
Royalties earned	$ 0
Royalties paid	$ 0
Number of shares into which remaining warrants is exercisable					200,000
Series A Preferred Shares
Founder Royalty arrangements
Research and development			$ 900

Net loss per share - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Numerator:
Net loss attributable to ordinary shareholders									$ (30,608)	$ (21,846)	$ (16,259)
Denominator:
Weighted average ordinary shares outstanding, basic and diluted	17,926,165	17,900,978	7,298,139	834,043	503,309	433,795	420,063	397,483	11,045,370	438,862	333,125
Net loss per share attributable to ordinary shareholders, basic and diluted	$ (0.25)	$ (0.53)	$ (1.40)	$ (7.80)	$ (13.19)	$ (17.73)	$ (11.85)	$ (6.38)	$ (2.77)	$ (49.78)	$ (48.81)

Net loss per share per share - Securities excluded from the diluted per share calculation (Details) - shares		12 Months Ended
	Mar. 07, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 28, 2019
Antidilutive securities
Antidilutive securities (in shares)		2,727,231	13,828,271	12,116,697
Remaining warrants exercisable		65,000			80,000
Convertible preferred shares (as converted to ordinary shares)
Antidilutive securities
Antidilutive securities (in shares)			11,532,659	9,641,740
Warrants to subscribe for convertible preferred shares (as adjusted to reflect the impact of the share capital reorganization and issuance of bonus shares (Note 1))
Antidilutive securities
Antidilutive securities (in shares)		92,885	1,347,953	1,347,953
Percentage of warrants exercise in conjunction with IPO	50.00%
Percentage of warrants expire	50.00%
Remaining warrants exercisable		65,000
Number of ordinary shares for warrants exercise		92,885
Restricted ordinary shares
Antidilutive securities
Antidilutive securities (in shares)			83,947	162,466
Options to purchase ordinary shares
Antidilutive securities
Antidilutive securities (in shares)		2,634,346	863,712	964,538

Benefit plans (Details) - USD ($)	12 Months Ended
Benefit plans (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
United States \| 401(k) Plan
Benefit plans
Contributions made	$ 200,000	$ 100,000	$ 42,000
Foreign Plan \| U.K. Plan
Benefit plans
Contributions made	$ 300,000	$ 200,000	$ 200,000

Related party transactions (Details) - USD ($)	12 Months Ended
Related party transactions (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Founders and initial investors \| Royalty Agreements
Related party transactions
Royalties earned	$ 0
Royalties paid	0
Chairman of Board of Directors \| Consultancy services with 10X Capital Inc.
Related party transactions
Amount of transaction	50,000	$ 200,000	$ 100,000
Chairman of Board of Directors \| Consultancy services with Stone Sunny Isles Inc.
Related party transactions
Amount of transaction	$ 100,000

Geographic information (Details) $ in Thousands	12 Months Ended
Geographic information (Details) $ in Thousands	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)
Geographic information
Number of geographic regions \| item	2
Long lived assets, including operating lease right of use assets	$ 4,348	$ 1,818
United States
Geographic information
Long lived assets, including operating lease right of use assets	2,017	498
United Kingdom
Geographic information
Long lived assets, including operating lease right of use assets	$ 2,331	$ 1,320

Selected Quarterly Financial Data (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Data (Unaudited)
Collaboration revenues	$ 5,281	$ 614	$ 1,522	$ 6,384	$ 1,057	$ 1,610	$ 1,661	$ 2,808	$ 13,801	$ 7,136	$ 2,060
Total operating expenses	10,045	10,867	9,510	9,678	8,599	7,967	6,619	5,697	40,100	28,882	18,273
Total other income (expense), net	220	440	(2,094)	(3,129)	901	(1,335)	(21)	(41)	(4,563)	(496)	(69)
Net loss before income tax provision	(4,544)	(9,813)	(10,082)	(6,423)	(6,641)	(7,692)	(4,979)	(2,930)	(30,862)	(22,242)	(16,282)
Benefit from income taxes	(138)	(331)	135	80				(396)	(254)	(396)	(23)
Net loss	$ (4,406)	$ (9,482)	$ (10,217)	$ (6,503)	$ (6,641)	$ (7,692)	$ (4,979)	$ (2,534)	$ (30,608)	$ (21,846)	$ (16,259)
Net loss per share attributable to ordinary shareholders, basic and diluted	$ (0.25)	$ (0.53)	$ (1.40)	$ (7.80)	$ (13.19)	$ (17.73)	$ (11.85)	$ (6.38)	$ (2.77)	$ (49.78)	$ (48.81)
Weighted average ordinary shares outstanding, basic and diluted	17,926,165	17,900,978	7,298,139	834,043	503,309	433,795	420,063	397,483	11,045,370	438,862	333,125

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References + Details

Subsequent events (Details) - Genentech Collaboration Agreement - Subsequent events $ in Millions	Feb. 21, 2020 USD ($)
Subsequent events
Number of Potential development candidates	4
Number of immuno oncology targets	2
Additional number of immuno oncology targets	2
Expansion Fee	$ 10.0
Upfront payment fee	30.0
Regulatory, and initial commercialization milestones, payments receivable	200.0
Sales milestone payments, receivable	$ 200.0
Royalty payable term from first commercial milestone	10 years
Minimum
Subsequent events
Success-based milestone payments per collaboration program	$ 10.0
Maximum
Subsequent events
Success-based milestone payments per collaboration program	$ 12.0