Bicycle Therapeutics (BCYC) 10-Q 7 Nov 19 2019 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Oct. 31, 2019
Document and Entity Information
Document Type	10-Q
Document Period End Date	Sep. 30, 2019
Entity Registrant Name	BICYCLE THERAPEUTICS plc
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 Shell Company	false
Entity Common Stock, Shares Outstanding		17,902,869
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Entity Central Index Key	0001761612
Amendment Flag	false
Entity Ex Transition Period	true

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets:
Cash	$ 95,954	$ 63,380
Accounts receivable	46	5,021
Prepaid expenses and other current assets	3,536	2,076
Research and development incentives receivable	10,714	6,292
Total current assets	110,250	76,769
Property and equipment, net	2,152	1,818
Operating lease right-of-use assets	2,177
Other assets	1,481	3,039
Total assets	116,060	81,626
Current liabilities:
Accounts payable	1,992	1,887
Accrued expenses and other current liabilities	6,035	7,032
Deferred revenue, current portion	808	10
Total current liabilities	8,835	8,929
Warrant liability		4,804
Operating lease liabilities	1,416
Deferred revenue, net of current portion	9,055	14,625
Other long-term liabilities	1,429	897
Total liabilities	20,735	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 September 30, 2019 and December 31, 2018, respectively; 17,902,869 shares issued and outstanding at September 30, 2019; 898,678 shares issued and 814,728 shares outstanding at December 31, 2018	226	10
Additional paid-in capital	193,850	1,857
Accumulated other comprehensive loss	(2,607)	(1,751)
Accumulated deficit	(96,144)	(69,942)
Total shareholders’ equity (deficit)	95,325	(69,826)
Total liabilities, convertible preferred shares and shareholders’ equity (deficit)	$ 116,060	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

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - £ / shares	Sep. 30, 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	17,902,869	898,678
Ordinary shares, shares outstanding	17,902,869	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

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Consolidated Statements of Operations and Comprehensive Loss
Collaboration revenues	$ 614	$ 1,610	$ 8,520	$ 6,079
Operating expenses:
Research and development	6,078	5,642	18,891	14,268
General and administrative	4,789	2,325	11,164	6,015
Total operating expenses	10,867	7,967	30,055	20,283
Loss from operations	(10,253)	(6,357)	(21,535)	(14,204)
Other income (expense):
Interest and other income	440	26	594	75
Other expense, net		(1,361)	(5,377)	(1,472)
Total other income (expense), net	440	(1,335)	(4,783)	(1,397)
Net loss before income tax provision	(9,813)	(7,692)	(26,318)	(15,601)
Benefit from income taxes	(331)	0	(116)	(396)
Net loss	(9,482)	(7,692)	(26,202)	(15,205)
Net loss attributable to ordinary shareholders	$ (9,482)	$ (7,692)	$ (26,202)	$ (15,205)
Net loss per share attributable to ordinary shareholders, basic and diluted	$ (0.53)	$ (17.73)	$ (3)	$ (36.44)
Weighted average ordinary shares outstanding, basic and diluted	17,900,978	433,795	8,734,943	417,223
Comprehensives Loss:
Net loss	$ (9,482)	$ (7,692)	$ (26,202)	$ (15,205)
Other comprehensive income (loss):
Foreign currency translation adjustment	(424)	(537)	(856)	(1,398)
Total comprehensive loss	$ (9,906)	$ (8,229)	$ (27,058)	$ (16,603)

Condensed Consolidated Statem_2

Condensed 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, 2017	$ 41,820	$ 54,621		$ 5	$ 838	$ 69	$ (48,096)	$ (47,184)
Beginning balance (in shares) at Dec. 31, 2017	2,800,001	3,947,198		368,995
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards				$ 1	53			54
Issuance of restricted share awards (in shares)				35,725
Issuance of ordinary shares upon exercise of share options (in shares)				9,002
Share based compensation expense					198			198
Foreign currency translation adjustment						1,796		1,796
Net loss							(2,534)	(2,534)
Ending balance at Mar. 31, 2018	$ 41,820	$ 54,621		$ 6	1,089	1,865	(50,630)	(47,670)
Ending balance (in shares) at Mar. 31, 2018	2,800,001	3,947,198		413,722
Beginning balance at Dec. 31, 2017	$ 41,820	$ 54,621		$ 5	838	69	(48,096)	(47,184)
Beginning balance (in shares) at Dec. 31, 2017	2,800,001	3,947,198		368,995
Increase (decrease) in shareholders' equity (deficit)
Foreign currency translation adjustment								(1,398)
Net loss								(15,205)
Ending balance at Sep. 30, 2018	$ 41,820	$ 54,621		$ 6	1,654	(1,329)	(63,301)	(62,970)
Ending balance (in shares) at Sep. 30, 2018	2,800,001	3,947,198		442,409
Beginning balance at Mar. 31, 2018	$ 41,820	$ 54,621		$ 6	1,089	1,865	(50,630)	(47,670)
Beginning balance (in shares) at Mar. 31, 2018	2,800,001	3,947,198		413,722
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards					26			26
Issuance of restricted share awards (in shares)				12,757
Issuance of ordinary shares upon exercise of share options (in shares)				359
Share based compensation expense					309			309
Foreign currency translation adjustment						(2,657)		(2,657)
Net loss							(4,979)	(4,979)
Ending balance at Jun. 30, 2018	$ 41,820	$ 54,621		$ 6	1,424	(792)	(55,609)	(54,971)
Ending balance (in shares) at Jun. 30, 2018	2,800,001	3,947,198		426,838
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards					27			27
Issuance of restricted share awards (in shares)				15,571
Share based compensation expense					203			203
Foreign currency translation adjustment						(537)		(537)
Net loss							(7,692)	(7,692)
Ending balance at Sep. 30, 2018	$ 41,820	$ 54,621		$ 6	1,654	(1,329)	(63,301)	(62,970)
Ending balance (in shares) at Sep. 30, 2018	2,800,001	3,947,198		442,409
Beginning balance at Dec. 31, 2018	$ 41,820	$ 54,621	$ 25,756
Beginning balance (in shares) at Dec. 31, 2018	2,800,001	3,947,198	1,323,248
Increase (decrease) in convertible preferred shares
Issuance of convertible preferred shares			$ 1,583
Issuance of convertible preferred shares (in shares)			80,385
Ending balance at Mar. 31, 2019	$ 41,820	$ 54,621	$ 27,339
Ending balance (in shares) at Mar. 31, 2019	2,800,001	3,947,198	1,403,633
Beginning balance at Dec. 31, 2018				$ 10	1,857	(1,751)	(69,942)	$ (69,826)
Beginning balance (in shares) at Dec. 31, 2018				814,728				814,728
Increase (decrease) in shareholders' equity (deficit)
Issuance of restricted share awards				$ 1	103			$ 104
Issuance of restricted share awards (in shares)				27,304
Issuance of ordinary shares upon exercise of share options (in shares)				3
Share based compensation expense					172			172
Foreign currency translation adjustment						1,080		1,080
Net loss							(6,503)	(6,503)
Ending balance at Mar. 31, 2019				$ 11	2,132	(671)	(76,445)	(74,973)
Ending balance (in shares) at Mar. 31, 2019				842,035
Beginning balance at Dec. 31, 2018	$ 41,820	$ 54,621	$ 25,756
Beginning balance (in shares) at Dec. 31, 2018	2,800,001	3,947,198	1,323,248
Ending balance (in shares) at Sep. 30, 2019	0	0	0
Beginning balance at Dec. 31, 2018				$ 10	1,857	(1,751)	(69,942)	$ (69,826)
Beginning balance (in shares) at Dec. 31, 2018				814,728				814,728
Increase (decrease) in shareholders' equity (deficit)
Reclassification of warrant liability to additional paid-in capital and exercise of warrants								$ 10,021
Foreign currency translation adjustment								(856)
Net loss								(26,202)
Ending balance at Sep. 30, 2019				$ 226	193,850	(2,607)	(96,144)	$ 95,325
Ending balance (in shares) at Sep. 30, 2019				17,902,869				17,902,869
Beginning balance at Mar. 31, 2019	$ 41,820	$ 54,621	$ 27,339
Beginning balance (in shares) at Mar. 31, 2019	2,800,001	3,947,198	1,403,633
Increase (decrease) in convertible preferred shares
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)
Beginning balance at Mar. 31, 2019				$ 11	2,132	(671)	(76,445)	$ (74,973)
Beginning balance (in shares) at Mar. 31, 2019				842,035
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)				702,557
Issuance of ADSs in initial public offering, net of underwriting discounts, commissions and offering expenses of $8.4 million				$ 59	56,469			56,528
Number of shares issued (in shares)				4,637,666
Issuance of restricted share awards				$ 1	292			293
Issuance of restricted share awards (in shares)				56,643
Issuance of ordinary shares upon exercise of share options					21			21
Issuance of ordinary shares upon exercise of share options (in shares)				14,301
Share based compensation expense					612			612
Foreign currency translation adjustment						(1,512)		(1,512)
Net loss							(10,217)	(10,217)
Ending balance at Jun. 30, 2019				$ 226	193,178	(2,183)	(86,662)	104,559
Ending balance (in shares) at Jun. 30, 2019				17,900,731
Ending balance (in shares) at Sep. 30, 2019	0	0	0
Increase (decrease) in shareholders' equity (deficit)
Issuance of ordinary shares upon exercise of share options (in shares)				2,138
Share based compensation expense					819			819
Public offering costs					(147)			(147)
Foreign currency translation adjustment						(424)		(424)
Net loss							(9,482)	(9,482)
Ending balance at Sep. 30, 2019				$ 226	$ 193,850	$ (2,607)	$ (96,144)	$ 95,325
Ending balance (in shares) at Sep. 30, 2019				17,902,869				17,902,869

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Convertible Preferred Shares and Shareholders’ Equity (Deficit) (Parenthetical) $ in Millions	3 Months Ended
	Jun. 30, 2019USD ($)
Condensed Consolidated Statements of Convertible Preferred Shares and Shareholders’ Equity (Deficit)
Offering expenses	$ 8.4

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities:
Net loss	$ (26,202)	$ (15,205)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	2,000	816
Depreciation and amortization	686	528
Change in fair value of warrant liability recorded as other expense	5,381	1,472
Changes in operating assets and liabilities:
Accounts receivable	5,064	(289)
Research and development incentives receivable	(4,813)	(821)
Prepaid expenses and other current assets	(1,638)	(1,902)
Operating lease right-of-use assets	528
Other assets	(216)	(315)
Accounts payable	516	(864)
Accrued expenses and other current liabilities	(611)	2,206
Lease liabilities	(526)
Deferred revenue	(4,502)	(3,258)
Other long-term liabilities	639	408
Net cash used in operating activities	(23,694)	(17,224)
Cash used in investing activities:
Purchases of property and equipment	(1,164)	(776)
Net cash used in investing activities	(1,164)	(776)
Cash flows from financing activities:
Gross proceeds from issues of shares	1,334
Proceeds from issuance of ADS in initial public offering, net of issuance costs	56,957
Proceeds from the exercise of share options	21
Proceeds from the exercise of warrants	6	1
Net cash provided by financing activities	58,318	1
Effect of exchange rate changes on cash	(886)	(1,742)
Net increase (decrease) in cash	32,574	(19,741)
Cash at beginning of period	63,380	67,663
Cash at end of period	95,954	47,922
Supplemental disclosure of cash flow information
Cash paid for income taxes	73
Cash paid for amounts included in the measurement of operating lease liabilities	447
Advance billings on deferred revenue included in accounts receivable		$ 5,353
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

Nature of the business and basi

Nature of the business and basis of presentation	9 Months Ended
	Sep. 30, 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 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 developing BT5528 and BT8009, which are BTCs targeting Ephrin type-A receptor 2 and Nectin‑4, respectively, and BT7480, which is a tumor-targeted immune cell agonist targeting Nectin-4 and agonizing CD137, for oncology indications. Bicycle -targeted innate immune activators, T-cell modulators, and tumor-targeted immune cell agonists. Beyond oncology, the Company is collaborating with biopharmaceutical companies and organizations in therapeutic areas that include anti-bacterial, cardiovascular, hematology, ophthalmology, dementia and respiratory indications. The accompanying condensed 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 condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”). Share capital reorganization On May 9, 2019, the Company’s board of directors and shareholders approved the reorganization of the Company’s share capital (the “Share Capital Reorganization”) 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 condensed consolidated financial statements have been adjusted to reflect this the Share Capital Reorganization for all periods presented. The number of ordinary shares that were 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 Company’s initial public offering (“IPO”) were adjusted accordingly, as well as the number of ordinary shares over which options and outstanding warrants 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 condensed consolidated financial statements previously presented the condensed consolidated results of operations of BTL. Following the completion of the Company’s re-registration in May 2019, the condensed consolidated financial statements of BTL became the historical condensed 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 condensed consolidated balance sheet. 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 condensed 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 $26.2 million for the nine months ended September 30, 2019. As of September 30, 2019, the Company had an accumulated deficit of $96.1 million. The Company expects to continue to generate operating losses in the foreseeable future. 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 these interim condensed 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 substantial 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 accounti

Summary of significant accounting policies	9 Months Ended
	Sep. 30, 2019
Summary of significant accounting policies
Summary of significant accounting policies	2. Summary of significant accounting policies The Company’s significant accounting policies are disclosed in the audited consolidated financial statements for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the Securities and Exchange Commission (“SEC”), on May 23, 2019. Since the date of such consolidated financial statements, there have been no changes to the Company’s significant accounting policies, other than those disclosed below. Unaudited Interim Financial Information Certain information in the footnote disclosures of the financial statements has been condensed or omitted pursuant to the rules and regulations of the SEC. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the SEC, on May 23, 2019. The accompanying condensed consolidated balance sheet at September 30, 2019, condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) for the three and nine months ended September 30, 2019 and 2018, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2019 and 2018 and the related financial information disclosed in these notes are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements for the year ended December 31, 2018, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2019, the results of its operations for the three and nine months ended September 30, 2019 and 2018, and its cash flows for the nine months ended September 30, 2019 and 2018. The results for the three and nine months ended September 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019, any other interim periods, or any future year or period. 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. 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 U.S. Dollar (“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 condensed consolidated statements of operations and comprehensive loss as incurred. The Company recorded a foreign exchange loss of $0.8 million and an exchange gain of $41,000 during the three months ended September 30, 2019 and 2018, respectively, and a foreign exchange loss of $0.4 million and an exchange gain of $0.4 million for the nine months ended September 30, 2019 and 2018, 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 foreign currency translation adjustment, which is included in the condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) as a component of accumulated other comprehensive income (loss). 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 condensed 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. 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 condensed 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 three and nine months ended September 30, 2019, the Company recognized $0.2 and $0.5 million, respectively, as a reduction of research and development expense related to government grant arrangements. There were no grant proceeds recognized for the three and nine month periods ended September 30, 2018. 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 condensed 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, but will impact implementation costs that are incurred for the remainder of 2019 and in future periods. 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

Fair value of financial assets and liabilities	9 Months Ended
	Sep. 30, 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 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 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 condensed consolidated balance sheet. As such, there is no warrant liability at September 30, 2019. The following table presents 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 nine months ended September 30, 2019 and the year ended December 31, 2018, there were no transfers between levels.

Property and equipment, net

Property and equipment, net	9 Months Ended
	Sep. 30, 2019
Property and equipment, net
Property and equipment, net	4. Property and equipment, net Property and equipment, net consisted of the following (in thousands): September 30, December 31, 2019 2018 Laboratory equipment $ 3,784 $ 3,356 Leasehold improvements 291 75 Computer equipment and software 222 221 Furniture and office equipment 113 99 4,410 3,751 Less: Accumulated depreciation and amortization (2,258) (1,933) $ 2,152 $ 1,818 Depreciation expense was $0.2 million and $0.7 million for the three and nine months ended September 30, 2019, and $0.2 million and $0.5 million for the three and nine months ended September 30, 2018, respectively.

Accrued expenses and other curr

Accrued expenses and other current liabilities	9 Months Ended
	Sep. 30, 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): September 30, December 31, 2019 2018 Accrued employee compensation and benefits $ 1,530 $ 1,610 Accrued external research and development expenses 2,628 3,814 Income taxes payable 11 15 Accrued professional fees 1,224 1,494 Current portion of operating lease liabilities 602 — Other 40 99 $ 6,035 $ 7,032

Convertible preferred shares

Convertible preferred shares	9 Months Ended
	Sep. 30, 2019
Convertible preferred shares
Convertible preferred shares	6. Convertible preferred shares The Company had 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 £13.00, 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

Warrant liability	9 Months Ended
	Sep. 30, 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). 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 nine months ended September 30, 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 condensed 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 condensed 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 September 30, 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. 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.

Ordinary shares

Ordinary shares	9 Months Ended
	Sep. 30, 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. Holders of ADSs are not treated as holders of the Company’s ordinary shares, unless they withdraw the ordinary shares underlying their ADSs in accordance with the deposit agreement and applicable laws and regulations. The depositary is the holder of the ordinary shares underlying the ADSs. Holders of ADSs therefore do not have any rights as holders of the Company’s ordinary shares, other than the rights that they have pursuant to the deposit agreement with the depositary. As of December 31, 2018 and September 30, 2019, the Company has not declared any dividends. As of September 30, 2019 and December 31, 2018, the Company’s authorized capital share consisted of 31,995,653 ordinary shares and 15,452,420 ordinary shares, respectively, with a nominal value of £0.01 per share.

Share-based compensation

Share-based compensation	9 Months Ended
	Sep. 30, 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 condensed 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 September 30, 2019, there were 939,089 shares available for issuance under the 2019 Plan. 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 September 30, 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 condensed consolidated statements of operations and comprehensive loss (in thousands): Three Nine Months Months Ended Ended September 30, September 30, 2019 2018 2019 2018 Research and development expenses $ 417 $ 123 $ 816 $ 421 General and administrative expenses 402 107 1,184 395 $ 819 $ 230 $ 2,000 $ 816 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 2,068,095 11.92 — — Exercised (16,442) 1.26 — — Forfeited (278,090) 3.65 — — Outstanding as of September 30, 2019 2,637,275 $ 9.29 9.27 $ 9,088 Vested and expected to vest as of September 30, 2019 512,710 $ 5.38 8.42 $ 3,602 Options exercisable as of September 30, 2019 512,710 $ 5.38 8.42 $ 3,602 The weighted average grant‑date fair value of share options granted during the nine months ended September 30, 2019 and 2018 was $4.81 per share and $1.87 per share, respectively. Total share-based compensation expense for share options granted was $0.8 million and $1.6 million for the three and nine months ended September 30, 2019, respectively, and $0.2 million and $0.7 million, for the three and nine months ended September 30, 2018, respectively. Expense for non-employee consultants for the three and nine months ended September 30, 2019 and 2018 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 was immaterial and $0.1 million during the three and nine months ended September 30, 2019, respectively, and was immaterial during the three and nine months ended September 30, 2018. The Company granted certain performance based vesting options for the purchase of an aggregate of zero and 70,875 ordinary shares during the nine months ended September 30, 2019 and 2018, 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 $31,000 and $0.1 during the three and nine months ended September 30, 2019, respectively, and $0.2 million and $0.6 million during the three and nine months ended September 30, 2018 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: Three Nine Months Months Ended Ended September 30, September 30, 2019 2018 2019 2018 Risk-free interest rate 1.7 % 3.0 % 2.2 % 2.5 % Expected volatility 77.0 % 76.0 % 78.3 % 75.8 % Expected dividend yield — — — — Expected term (in years) 6.00 6.07 5.88 6.07 As of September 30, 2019, total unrecognized compensation expense related Restricted shares The Company had 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 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 September 30, 2019 — $ — In Total The fair value of employee restricted share awards vested, based on estimated fair values of the ordinary shares underlying the restricted share awards on the day of vesting, was zero and $0.7 million during the three and nine months ended September 30, 2019, respectively, and $34,000 and $0.1 million during the three and nine months ended September 30, 2018, respectively As of September 30, 2019, there was

Significant agreements

Significant agreements	9 Months Ended
	Sep. 30, 2019
Significant agreements
Significant agreements	10. Significant agreements For the three and nine months ended September 30, 2019 and 2018, the Company had collaboration agreements with AstraZeneca AB (“AstraZeneca”), Sanofi (formerly Bioverativ), Oxurion (formerly ThromboGenics) and the Dementia Discovery Fund. The following table summarizes the revenue recognized in the Company’s condensed consolidated statements of operations and comprehensive loss from the Company’s collaboration agreements (in thousands): Three Months Nine Months Ended Ended September 30, September 30, 2019 2018 2019 2018 Collaboration revenues AstraZeneca $ 441 $ 388 $ 1,229 $ 1,078 Sanofi — 1,047 6,016 3,258 Oxurion — 175 — 1,743 Dementia Discovery Fund 173 — 275 — Material transfer agreement — — 1,000 — Total collaboration revenues $ 614 $ 1,610 $ 8,520 $ 6,079 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) to 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 it is responsible to 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 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 Target One Research License and Related Services and the Target Two Research License and Related Services are 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 transaction price allocated to each performance obligation was initially $0.6 million. 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 three months and nine months ended September 30, 2019, the Company recognized zero and $0.2 million, respectively, and for the three and nine months ended September 30, 2018 the Company recognized $0.2 million and $0.8 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 September 30, 2019 and December 31, 2018, the Company recorded zero deferred revenue and $24,000 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, which was 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 each 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 at the inception of the arrangement, 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 determined to be $5.7 million at the inception of the arrangement, 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 at the inception of the arrangement 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 nine months ended September 30, 2019, the Company commenced research and development services related to the fourth and fifth targets. For the three and nine months ended September 30, 2019, the Company recognized $0.4 million and $0.2 million of revenue, respectively, and for the three and nine months ended September 30, 2018, the Company recognized $1.0 million and $0.3 million of revenue for the Target Three Research License and Related Service, and research and development services for the fourth target and fifth targets related to the May 2018 AstraZeneca Option Exercise. As of September 30, 2019 and December 31, 2018, the Company recorded $4.5 million and $4.7 million of deferred revenue, respectively, 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 will provide for 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 will use its bicyclic peptide screening platform to perform research and development services for the programs and Sanofi has 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 is 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 is 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 can, at its sole discretion, select a certain number of collaboration compounds to move forward into the Joint Research Term. Upon selection of the collaboration compounds, Sanofi is required to pay an option fee. During the Joint Research Term, the Company and Sanofi will jointly conduct research and development activities which will include lead optimization of lead compounds, in preparation for lead collaboration product nomination (“Joint Research Term”). Sanofi may, at its sole discretion, approve any compound to be progressed into drug development and upon the selection of each collaboration product candidate, Sanofi shall pay $5.0 million as an option fee, in order to obtain worldwide development and exploitation rights for that collaboration product. Each research program shall continue for an initial period of three years (the “Research Term”) unless a program is abandoned by Sanofi or extended for up to one year. The first year of each Research Term shall be the BV Bicycle Research Term and the remaining part of the Research Term, including any extensions of the Research Term, shall be 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 is governed by a joint steering committee (“JSC”) formed by an equal number of representatives from the Company and Sanofi. The JSC oversees, review and recommends 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 is 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 has 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 would be 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 is 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 is eligible for up to $55.0 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 collaboration product. Regulatory milestone payments are triggered upon approval to market a product candidate by the FDA or other global regulatory authorities. Commercial milestone payments are 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 are 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 are subject to certain reductions, including for instances where Sanofi faces generic competition in certain countries. 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 Sanofi. 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 may terminate the Sanofi 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 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 may 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 has 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 is not a material right, as the option does not provide a discount that Sanofi otherwise would not have received. The Company’s participation in the JSC 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 are not performance obligations at the inception of the arrangement, as they are optional services that will be performed if Sanofi selects collaboration compounds for lead optimization. The amount paid by Sanofi for the services during the Joint Research Team 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 $14.2 million, consisting of the $10.0 million upfront payment and non‑refundable research and development funding of $4.2 million. The Company may 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 are excluded from the transaction price as they relate to fees and milestones that can 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 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 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 at the inception of the arrangement is 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 will recognize revenue related to amounts allocated to the Sickle Cell Research License and Related Services and the Hemophilia Research License and Related Services obligations 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 when the underlying option is exercised or upon expiry of the option. During the nine months ended September 30, 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. As a result, the amount allocated to the Sickle Cell License Option Material Right of $5.3 million was recognized into revenue during the nine months ended September 30, 2019. The collaboration with Sanofi was terminated effective October 23, 2019, and as a result, deferred revenue related to amounts allocated to the Hemophilia License Option Material Right will be recognized in the fourth quarter of 2019. The Company recognized zero and $6.0 million of collaboration revenue for the three and nine months ended September 30, 2019, respectively, and $1.0 million and $3.3 million of collaboration revenue for the three and nine months ended September 30, 2018, respectively, related to its collaboration with Sanofi. As of September 30, 2019, and December 31, 2018, the Company recorded deferred revenue of $4.5 million and $9.9 million, respectively, related to its collaboration with Sanofi. Oxurion Collaboration Agreement Summary of Agreement In August 2013, the Company entered into a Research Collaboration and License Agreement with Oxurion (the “Oxurion Collaboration Agreement”). Under the Oxurion Collaboration Agreement, the Company was 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, 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 ob

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Taxes
Income Taxes	11. Income Taxes During the three and nine months ended September 30, 2019, the Company recorded an income tax benefit of $0.3 million and $0.1 million, respectively. During the three and nine months ended September 30, 2018, the Company recorded an income tax benefit of zero and $0.4 million, 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 has therefore not paid United Kingdom corporation tax. The Company's income tax benefit is mainly the result of deferred tax assets benefitted 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 benefit from income taxes for the nine months ended September 30, 2018 is limited to the total tax benefit the Company expects to realize for the respective year, since the Company incurred losses in the respective year to date periods that exceeds the expected annual loss. 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 Company recorded a valuation allowance against all of its U.K. deferred tax assets as of September 30, 2019 and December 31, 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 from 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 from income taxes shown on the condensed 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.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2019
Commitments and Contingencies
Commitments and Contingencies	12. Commitments and Contingencies Leases In September 2015, the Company entered into a tenancy agreement for office and laboratory space in Building 260 Babraham Research Campus, Cambridge, U.K. 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 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 condensed 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 condensed consolidated balance sheets. With the adoption of ASC 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 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 three and nine months ended September 30, 2018, 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 the three and nine months ended September 30, 2018, the Company recognized total rent expense of $0.3 million and $0.8 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 condensed consolidated statement of operations and comprehensive loss are as follows (in thousands): Three Nine Months Months Ended Ended September 30, September 30, 2019 2019 Operating lease cost $ 219 $ 669 Variable lease cost 91 282 Total lease cost $ 310 $ 951 Weighted‑average remaining operating lease term (years) 2.9 2.9 Weighted‑average discount rate 8.50 % 8.50 % The following table summarizes the maturities of the Company’s operating leases as of September 30, 2019 (in thousands): Year Ending December 31, 2019 $ 434 2020 848 2021 753 2022 443 2023 — Present value adjustment (460) Total lease liabilities $ 2,018 Less: current lease liabilities (602) Long term lease liabilities $ 1,416 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 filed a complaint in the District Court of The Hague against Pepscan Systems B.V. (“Pepscan”) to contest the right of Pepscan to terminate a non‑exclusive patent license agreement entered into with Pepscan in 2009 and 2010 (“PLA”). 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 September 30, 2019 and December 31, 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 Agreement, 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. 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 condensed consolidated financial statements as of September 30, 2019 and December 31, 2018.

Net loss per share

Net loss per share	9 Months Ended
	Sep. 30, 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): Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Numerator: Net loss attributable to ordinary shareholders $ (9,482) $ (7,692) $ (26,202) $ (15,205) Denominator: Weighted average ordinary shares outstanding, basic and diluted 17,900,978 433,795 8,734,943 417,223 Net loss per share attributable to ordinary shareholders, basic and diluted $ (0.53) $ (17.73) $ (3.00) $ (36.44) 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: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Convertible preferred shares (as converted to ordinary shares) — 9,641,740 — 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) 114,320 1,347,953 114,320 1,347,953 Restricted ordinary shares — 123,735 — 123,735 Options to purchase ordinary shares 2,637,275 971,079 2,637,275 971,079 2,751,595 12,084,507 2,751,595 12,084,507 (1) 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. (2) At September 30, 2019, 80,000 warrants are outstanding which are exercisable into 114,320 ordinary shares (Note 6).

Benefit plans

Benefit plans	9 Months Ended
	Sep. 30, 2019
Benefit plans
Benefit plans	14. Benefit plans The Company established a defined‑contribution savings plan under Section 401(k) of the United States Internal Revenue 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 three months ended September 30, 2019 and 2018 the Company made contributions totaling $26,000 and $23,000, respectively, to the 401(k) Plan. During each of the nine months ended September 30, 2019 and 2018, the Company made contributions totaling $0.1 million to the 401(k) Plan. The Company provides a pension contribution plan for its employees in the United Kingdom, pursuant to which the Company contributes each year amounts of up to 12% of their annual base salary (“U.K Plan”). During each of the three months ended September 30, 2019 and 2018, the Company made contributions totaling $0.1 million to the U.K. Plan. During each of the nine months ended September 30, 2019 and 2018, the Company made contributions totaling $0.2 million to the U.K. Plan.

Related party transactions

Related party transactions	9 Months Ended
	Sep. 30, 2019
Related party transactions
Related party transactions	15. Related party transactions The Company has entered into a Founder Royalty Agreement with its founders and initial investors (Note 12). No royalties have been earned or paid under the Founder Royalty Agreement to date. The former Chairman of the Company’s Board of Directors is associated with 10X Capital Inc., which provided consultancy services to the Company totaling zero and $50,000 during the three and nine months ended September 30, 2019, respectively, and $25,000 and $0.1 million during the three and nine months ended September 30, 2018, respectively.

Geographic information

Geographic information	9 Months Ended
	Sep. 30, 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, including operating lease right‑of‑use assets, held in different geographic regions is presented in the table below (in thousands): September 30, December 31, 2019 2018 United States $ 2,020 $ 498 United Kingdom 2,309 1,320 $ 4,329 $ 1,818 The Company’s collaboration revenues are attributed to the operations of the Company in the United Kingdom.

Subsequent events

Subsequent events	9 Months Ended
	Sep. 30, 2019
Subsequent events
Subsequent events	17. Subsequent events Effective October 23, 2019, Sanofi terminated the Sanofi Collaboration Agreement. As a result, deferred revenue related to amounts allocated to the Hemophilia License Option Material Right of approximately $4.5 million will be recognized as collaboration revenue in the fourth quarter of 2019.

Summary of significant accoun_2

Summary of significant accounting policies (Policies)	9 Months Ended
	Sep. 30, 2019
Summary of significant accounting policies
Unaudited Interim Financial Information	Unaudited Interim Financial Information Certain information in the footnote disclosures of the financial statements has been condensed or omitted pursuant to the rules and regulations of the SEC. These unaudited condensed consolidated financial statements should be read in conjunction with the Company’s audited consolidated financial statements and notes thereto for the year ended December 31, 2018 included in the Company’s final prospectus for the IPO filed pursuant to Rule 424(b) under the Securities Act, with the SEC, on May 23, 2019. The accompanying condensed consolidated balance sheet at September 30, 2019, condensed consolidated statements of operations and comprehensive loss, condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) for the three and nine months ended September 30, 2019 and 2018, and the condensed consolidated statements of cash flows for the nine months ended September 30, 2019 and 2018 and the related financial information disclosed in these notes are unaudited. The unaudited interim financial statements have been prepared on the same basis as the audited annual financial statements for the year ended December 31, 2018, and, in the opinion of management, reflect all adjustments, consisting of normal recurring adjustments, necessary for the fair presentation of the Company’s financial position as of September 30, 2019, the results of its operations for the three and nine months ended September 30, 2019 and 2018, and its cash flows for the nine months ended September 30, 2019 and 2018. The results for the three and nine months ended September 30, 2019 are not necessarily indicative of the results to be expected for the year ending December 31, 2019, any other interim periods, or any future year or period.
Foreign currency and currency translation	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. 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 U.S. Dollar (“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 condensed consolidated statements of operations and comprehensive loss as incurred. The Company recorded a foreign exchange loss of $0.8 million and an exchange gain of $41,000 during the three months ended September 30, 2019 and 2018, respectively, and a foreign exchange loss of $0.4 million and an exchange gain of $0.4 million for the nine months ended September 30, 2019 and 2018, 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 foreign currency translation adjustment, which is included in the condensed consolidated statements of convertible preferred shares and shareholders’ equity (deficit) as a component of accumulated other comprehensive income (loss).
Leases	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 condensed 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.
Government grants	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 condensed 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 three and nine months ended September 30, 2019, the Company recognized $0.2 and $0.5 million, respectively, as a reduction of research and development expense related to government grant arrangements. There were no grant proceeds recognized for the three and nine month periods ended September 30, 2018.
Recently adopted accounting pronouncements	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 condensed 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, but will impact implementation costs that are incurred for the remainder of 2019 and in future periods. 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 asset_2

Fair value of financial assets and liabilities (Tables)	9 Months Ended
	Sep. 30, 2019
Fair value of financial assets and liabilities
Schedule of financial assets and liabilities measured at fair value on a recurring basis	The following table presents 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 (Ta

Property and equipment, net (Tables)	9 Months Ended
	Sep. 30, 2019
Property and equipment, net
Schedule of property and equipment, net	Property and equipment, net consisted of the following (in thousands): September 30, December 31, 2019 2018 Laboratory equipment $ 3,784 $ 3,356 Leasehold improvements 291 75 Computer equipment and software 222 221 Furniture and office equipment 113 99 4,410 3,751 Less: Accumulated depreciation and amortization (2,258) (1,933) $ 2,152 $ 1,818

Accrued expenses and other cu_2

Accrued expenses and other current liabilities (Tables)	9 Months Ended
	Sep. 30, 2019
Accrued expenses and other current liabilities
Schedule of accrued expenses and other current liabilities	Accrued expenses and other current liabilities consisted of the following (in thousands): September 30, December 31, 2019 2018 Accrued employee compensation and benefits $ 1,530 $ 1,610 Accrued external research and development expenses 2,628 3,814 Income taxes payable 11 15 Accrued professional fees 1,224 1,494 Current portion of operating lease liabilities 602 — Other 40 99 $ 6,035 $ 7,032

Warrant liability (Tables)

Warrant liability (Tables)	9 Months Ended
	Sep. 30, 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 September 30, 2019 $ —

Share-based compensation (Table

Share-based compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share-based compensation
Schedule of share based compensation expense	The Company recorded share‑based compensation expense in the following expense categories of its condensed consolidated statements of operations and comprehensive loss (in thousands): Three Nine Months Months Ended Ended September 30, September 30, 2019 2018 2019 2018 Research and development expenses $ 417 $ 123 $ 816 $ 421 General and administrative expenses 402 107 1,184 395 $ 819 $ 230 $ 2,000 $ 816
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 2,068,095 11.92 — — Exercised (16,442) 1.26 — — Forfeited (278,090) 3.65 — — Outstanding as of September 30, 2019 2,637,275 $ 9.29 9.27 $ 9,088 Vested and expected to vest as of September 30, 2019 512,710 $ 5.38 8.42 $ 3,602 Options exercisable as of September 30, 2019 512,710 $ 5.38 8.42 $ 3,602
Schedule of assumptions used to determine the fair value of share options granted	Three Nine Months Months Ended Ended September 30, September 30, 2019 2018 2019 2018 Risk-free interest rate 1.7 % 3.0 % 2.2 % 2.5 % Expected volatility 77.0 % 76.0 % 78.3 % 75.8 % Expected dividend yield — — — — Expected term (in years) 6.00 6.07 5.88 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 September 30, 2019 — $ —

Significant agreements (Tables)

Significant agreements (Tables)	9 Months Ended
	Sep. 30, 2019
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Summary of revenue recognized from collaboration arrangements	The following table summarizes the revenue recognized in the Company’s condensed consolidated statements of operations and comprehensive loss from the Company’s collaboration agreements (in thousands): Three Months Nine Months Ended Ended September 30, September 30, 2019 2018 2019 2018 Collaboration revenues AstraZeneca $ 441 $ 388 $ 1,229 $ 1,078 Sanofi — 1,047 6,016 3,258 Oxurion — 175 — 1,743 Dementia Discovery Fund 173 — 275 — Material transfer agreement — — 1,000 — Total collaboration revenues $ 614 $ 1,610 $ 8,520 $ 6,079
Summary of changes in the balances of the Company’s contract assets and liabilities	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 Balance at Impact of Balance at Beginning of Exchange End of Period Additions Deductions Rates Period Period ended September 30, 2019 Contract assets $ — $ 149 $ (103) $ — $ 46 Contract liabilities: Deferred revenue AstraZeneca collaboration deferred revenue 4,727 24 (35) (167) 4,549 Sanofi collaboration deferred revenue 9,908 — (5,286) (116) 4,506 DDF collaboration deferred revenue — 1,114 (275) (31) 808 Total deferred revenue $ 14,635 $ 1,138 $ (5,596) $ (314) $ 9,863
Summary of recognition of revenues as a result of changes in contract asset and contract liability balances	During the three and nine months ended September 30, 2019 and 2018, 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): Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Revenue recognized in the period from: Revenue recognized based on proportional performance $ (173) $ (1,121) $ (310) $ (3,408) Revenue recognized based on expiration of material rights — — (5,286) — Total $ (173) $ (1,121) $ (5,596) $ (3,408)
AstraZeneca
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
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 at the inception of the arrangement 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
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
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 at the inception of the arrangement is 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

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 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 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	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 condensed consolidated statement of operations and comprehensive loss are as follows (in thousands): Three Nine Months Months Ended Ended September 30, September 30, 2019 2019 Operating lease cost $ 219 $ 669 Variable lease cost 91 282 Total lease cost $ 310 $ 951 Weighted‑average remaining operating lease term (years) 2.9 2.9 Weighted‑average discount rate 8.50 % 8.50 %
Schedule of maturities of operating leases	The following table summarizes the maturities of the Company’s operating leases as of September 30, 2019 (in thousands): Year Ending December 31, 2019 $ 434 2020 848 2021 753 2022 443 2023 — Present value adjustment (460) Total lease liabilities $ 2,018 Less: current lease liabilities (602) Long term lease liabilities $ 1,416

Net loss per share (Tables)

Net loss per share (Tables)	9 Months Ended
	Sep. 30, 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): Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Numerator: Net loss attributable to ordinary shareholders $ (9,482) $ (7,692) $ (26,202) $ (15,205) Denominator: Weighted average ordinary shares outstanding, basic and diluted 17,900,978 433,795 8,734,943 417,223 Net loss per share attributable to ordinary shareholders, basic and diluted $ (0.53) $ (17.73) $ (3.00) $ (36.44)
Schedule of antidilutive securities excluded from computation of net loss per share attributable to ordinary shareholders	Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Convertible preferred shares (as converted to ordinary shares) — 9,641,740 — 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) 114,320 1,347,953 114,320 1,347,953 Restricted ordinary shares — 123,735 — 123,735 Options to purchase ordinary shares 2,637,275 971,079 2,637,275 971,079 2,751,595 12,084,507 2,751,595 12,084,507 (1) 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. At September 30, 2019, 80,000 warrants are outstanding which are exercisable into 114,320 ordinary shares (Note 6).

Geographic information (Tables)

Geographic information (Tables)	9 Months Ended
	Sep. 30, 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, including operating lease right‑of‑use assets, held in different geographic regions is presented in the table below (in thousands): September 30, December 31, 2019 2018 United States $ 2,020 $ 498 United Kingdom 2,309 1,320 $ 4,329 $ 1,818

Nature of the business and ba_2

Nature of the business and basis of presentation - Share capital reorganization and share split (Details)	May 09, 2019
Nature of business and basis of presentation
Stock split of common stock for bonus shares	1.429

Nature of the business and ba_3

Nature of the business and basis of presentation - Initial public offering (Details) $ / shares in Units, $ in Millions	May 28, 2019$ / sharesshares	Jun. 30, 2019shares	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)shares
Share capital reorganization and share split
Offering expenses | $				$ 8.4
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
IPO
Share capital reorganization and share split
Shares issued (in shares)	4,333,333
Share price (in dollars per share) | $ / shares	$ 14
Proceeds from IPO, net | $			$ 56.4
Underwriting discounts and commissions | $			4.5
Offering expenses | $			$ 4
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 ba_4

Nature of the business and basis of presentation- Liquidity (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Nature of business and basis of presentation
Net loss	$ 9,482	$ 10,217	$ 6,503	$ 7,692	$ 4,979	$ 2,534	$ 26,202	$ 15,205
Accumulated deficit	$ 96,144						$ 96,144		$ 69,942

Summary of significant accoun_3

Summary of significant accounting policies - Foreign currency and currency translation (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Summary of significant accounting policies
Foreign exchange (loss) gains	$ (800,000)	$ 41,000	$ (400,000)	$ 400,000

Summary of significant accoun_4

Summary of significant accounting policies - Government grants (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Summary of significant accounting policies
Reduction of research and development	$ 0.2	$ 0	$ 0.5	$ 0

Summary of significant accoun_5

Summary of significant accounting policies - Recently adopted accounting pronouncements (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jan. 01, 2019
Recently adopted accounting pronouncements
Right-of-use assets	$ 2,177
ASU 2016-02, Leases (Topic 842)
Recently adopted accounting pronouncements
Right-of-use assets		$ 2,700
Lease liabilities		$ 2,600

Fair value of financial asset_3

Fair value of financial assets and liabilities - Financial assets and liabilities measured at fair value (Details) - USD ($) $ in Thousands	Sep. 30, 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 asset_4

Fair value of financial assets and liabilities - Transfers between levels (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 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 (De

Property and equipment, net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Property and equipment, net
Property and equipment, gross	$ 4,410		$ 4,410		$ 3,751
Less: Accumulated depreciation and amortization	(2,258)		(2,258)		(1,933)
Property and equipment, net	2,152		2,152		1,818
Depreciation expense	200	$ 200	700	$ 500
Laboratory equipment
Property and equipment, net
Property and equipment, gross	3,784		3,784		3,356
Leasehold improvements
Property and equipment, net
Property and equipment, gross	291		291		75
Computer equipment and software
Property and equipment, net
Property and equipment, gross	222		222		221
Furniture and office equipment
Property and equipment, net
Property and equipment, gross	$ 113		$ 113		$ 99

Accrued expenses and other cu_3

Accrued expenses and other current liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accrued expenses and other current liabilities
Accrued employee compensation and benefits	$ 1,530	$ 1,610
Accrued external research and development expenses	2,628	3,814
Income taxes payable	11	15
Accrued professional fees	1,224	1,494
Current lease liabilities	602
Other	40	99
Accrued expenses and other current liabilities	$ 6,035	$ 7,032

Convertible preferred shares (D

Convertible preferred shares (Details) $ / shares in Units, $ in Thousands	May 28, 2019$ / sharesshares	Jan. 03, 2019USD ($)shares	Dec. 20, 2018USD ($)shares	Oct. 27, 2017USD ($)shares	May 26, 2017USD ($)shares	Jun. 30, 2019shares	Sep. 30, 2019USD ($)	Jan. 03, 2019£ / shares	Dec. 20, 2018£ / shares	Oct. 27, 2017£ / shares	May 26, 2017£ / shares
Convertible preferred shares
Gross proceeds from issues of shares | $							$ 1,334
IPO
Convertible preferred shares
Number of shares issued (in shares)	4,333,333
Share price (in dollars per share) | $ / shares	$ 14
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
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 price (in dollars per share) | £ / shares										£ 13	£ 11.2278
Gross proceeds from issues of shares | $				$ 6,600	$ 51,900
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 price (in dollars per share) | £ / shares								£ 15.55	£ 15.55
Gross proceeds from issues of shares | $		$ 1,600	$ 26,100

Warrant liability - Warrants in

Warrant liability - Warrants information (Details) $ in Thousands	May 28, 2019shares	Mar. 07, 2019	Dec. 20, 2018shares	Oct. 27, 2017£ / sharesshares	May 26, 2017£ / sharesshares	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019£ / shares
Class of Warrant or Right [Line Items]
Exercise price of warrants | £ / shares								£ 0.01
Number of shares issued for warrant exercise	171,480
Remaining warrants exercisable	80,000
Number of shares into which remaining warrants is exercisable	114,320
Change in fair value of warrants | $						$ 5,381	$ 1,472
Other expenses
Class of Warrant or Right [Line Items]
Change in fair value of warrants | $						$ 100
Series A Preferred Shares
Class of Warrant or Right [Line Items]
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
Class of Warrant or Right [Line Items]
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 price (in dollars per share) | £ / 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-forwar

Warrant liability - Roll-forward of fair values of warrant liability (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Roll-forward of the fair values of the Company’s warrant liability
Fair value at the beginning		$ 4,804
Change in fair value of warrant liability recorded as other expense		5,381	$ 1,472
Conversion of warrant liability to equity upon closing of IPO and exercise of warrants	$ (10,027)	(10,021)
Impact of exchange rates on translation of warrant liability to USD included in accumulated other comprehensive income (loss)		$ (164)

Warrant liability - Unobservabl

Warrant liability - Unobservable inputs (Details)	Mar. 07, 2019	Sep. 30, 2019£ / shares	May 28, 2019Y$ / shares£ / shares	Dec. 31, 2018Y$ / shares£ / shares
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Exercise price of warrants		£ 0.01
Series B1 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Percentage of warrants exercisable in conjunction with the IPO	50.00%
Percentage of warrants to expire in conjunction with the IPO	50.00%
Risk free rate | Series A Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability			2.2	2.6
Risk free rate | Series B1 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability			2.1	2.5
Expected term (years) | Series A Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability | Y			8	8.4
Expected term (years) | Series B1 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability | Y			5.8	6.25
Expected volatility | Series A Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability			74.7	75.4
Expected volatility | Series B1 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability			78.2	79.6
Exercise price | Series A Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability			0.01	0.01
Exercise price | Series B1 Warrants
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
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
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
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
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
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
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Fair value measurement of the warrant liability				50

Ordinary shares (Details)

Ordinary shares (Details)	9 Months Ended
	Sep. 30, 2019Vote£ / sharesshares	Dec. 31, 2018£ / sharesshares
Ordinary shares
Votes per 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 (Detai

Share-based compensation (Details)	1 Months Ended	9 Months Ended	12 Months Ended
	May 31, 2019shares	Sep. 30, 2019$ / sharesshares	Dec. 31, 2018$ / shares	Dec. 31, 2017	May 27, 2019£ / shares
Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercise price | $ / shares		$ 9.29	$ 1.01
Employee Share Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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%
2019 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of ordinary shares reserved for issuance	2,470,583
2019 Plan | Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of annual increase in reserves on total number of ordinary shares outstanding	4.00%
Number of shares available for issuance		939,089
Contractual life	10 years
2019 Plan | Stock option | First anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage	25.00%
2019 Plan | Stock option | 36 equal monthly installments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of equal monthly installments for vesting remaining awards	36 months
2019 Plan | Minimum | Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	3 years
2019 Plan | Maximum | Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Pre-IPO Share Options and restricted shares | Stock option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Contractual life		10 years
Vesting period		4 years
Pre-IPO Share Options and restricted shares | Stock option | First anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage		25.00%
Pre-IPO Share Options and restricted shares | Stock option | 36 equal monthly installments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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 Arrangement by Share-based Payment Award [Line Items]
Exercise price | £ / shares					£ 0.01
Pre-IPO Share Options and restricted shares | Performance based option | First anniversary
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage			20.00%	20.00%
Pre-IPO Share Options and restricted shares | Performance based option | 36 equal monthly installments
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
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 Arrangement by Share-based Payment Award [Line Items]
Vesting Percentage			20.00%	20.00%

Share-based compensation - Shar

Share-based compensation - Share based compensation expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share based compensation expense
Total share-based compensation expense	$ 819	$ 230	$ 2,000	$ 816
Research and development expenses
Share based compensation expense
Total share-based compensation expense	417	123	816	421
General and administrative expenses
Share based compensation expense
Total share-based compensation expense	$ 402	$ 107	$ 1,184	$ 395

Share-based compensation - Sh_2

Share-based compensation - Share options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended		12 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Additional Information
Total share-based compensation expense	$ 819			$ 230			$ 2,000	$ 816
Ordinary Shares
Number of Shares
Exercised	(2,138)	(14,301)	(3)		(359)	(9,002)
Stock option
Number of Shares
Outstanding number of shares at beginning			863,712				863,712
Granted							2,068,095
Exercised							(16,442)
Forfeited							(278,090)
Outstanding number of shares at end	2,637,275						2,637,275		863,712
Number of shares vested and expected to vest	512,710						512,710
Number of shares options exercisable	512,710						512,710
Weighted Average Exercise Price
Weighted average exercise price at beginning			$ 1.01				$ 1.01
Granted							11.92
Exercised							1.26
Forfeited							3.65
Weighted average exercise price at ending	$ 9.29						9.29		$ 1.01
Weighted average exercise price, vested and expected to vest	5.38						5.38
Weighted average exercise price, options exercisable	$ 5.38						$ 5.38
Weighted Average Contractual Term
Weighted average contractual term outstanding							9 years 3 months 7 days		8 years 9 months
Weighted average contractual term vested and expected to vest							8 years 5 months 1 day
Weighted average contractual term options exercisable							8 years 5 months 1 day
Aggregate Intrinsic Value
Aggregate intrinsic value outstanding	$ 9,088						$ 9,088		$ 3,292
Exercised	100			100			100	$ 100
Aggregate intrinsic value, vested and expected to vest	3,602						3,602
Aggregate intrinsic value, options exercisable	3,602						$ 3,602
Additional Information
Weighted average grant-date fair value of share options granted (per share)							$ 4.81	$ 1.87
Total share-based compensation expense	800			200			$ 1,600	$ 700
Aggregate intrinsic value of share options	100			100			$ 100	$ 100
Performance based option
Number of Shares
Granted							0	70,875
Additional Information
Total share-based compensation expense	$ 31,000			$ 200			$ 100	$ 600
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 - Sh_3

Share-based compensation - Share option valuation (Details) - Stock option - Employees and directors - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Risk-free interest rate	1.70%	3.00%	2.20%	2.50%
Expected volatility	77.00%	76.00%	78.30%	75.80%
Expected term (in years)	6 years	6 years 26 days	5 years 10 months 17 days	6 years 26 days
Share-based Payment Arrangement, Nonvested Award, Cost Not yet Recognized
Total unrecognized compensation expense related to the unvested employee and director	$ 11.4		$ 11.4
Unrecognized compensation cost expected to be recognized over a weighted average period			2 years 9 months 18 days

Share-based compensation - Rest

Share-based compensation - Restricted shares (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)$ / sharesshares	Sep. 30, 2018USD ($)	Sep. 30, 2019GBP (£)	Sep. 30, 2019USD ($)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
Total share-based compensation expense	$ 819,000	$ 230,000	$ 2,000,000	$ 816,000
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
Incremental share based compensation expense	0
Restricted shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Repurchase rights aggregate consideration | £					£ 1
Number of shares
Unvested restricted ordinary shares at beginning | shares			83,947
Vested | 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
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
Incremental share based compensation expense			$ 200,000
Total share-based compensation expense	0	25,000	400,000	100,000
Restricted shares | Employees and directors
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
Unrecognized compensation cost						$ 0
Restricted shares | Employee
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures
Fair value of employee restricted share awards vested	$ 0	$ 34,000	$ 700,000	$ 100,000

Significant agreements - Collab

Significant agreements - Collaboration revenues (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Significant agreements
Collaboration revenues	$ 614	$ 1,610	$ 8,520	$ 6,079
AstraZeneca
Significant agreements
Collaboration revenues	441	388	1,229	1,078
Sanofi
Significant agreements
Collaboration revenues	0	1,047	6,016	3,258
Oxurion
Significant agreements
Collaboration revenues	0	175	0	1,743
Dementia Discovery Fund
Significant agreements
Collaboration revenues	173	0	275	0
Material transfer agreement
Significant agreements
Collaboration revenues	$ 0	$ 0	$ 1,000	$ 0

Significant agreements - AstraZ

Significant agreements - AstraZeneca Collaboration Agreement (Details)

1 Months Ended

3 Months Ended

9 Months Ended

May 31, 2019employee

May 31, 2018USD ($)

Aug. 31, 2017

Nov. 30, 2016USD ($)employeeitem

Sep. 30, 2019USD ($)

Sep. 30, 2018USD ($)

Sep. 30, 2019USD ($)

Sep. 30, 2018USD ($)

Jul. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2017USD ($)

Oct. 31, 2017USD ($)

Significant agreements

Collaboration revenues

$ 614,000

$ 1,610,000

$ 8,520,000

$ 6,079,000

Deferred revenue

9,863,000

9,863,000

$ 14,635,000

$ 14,467,000

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

441,000

388,000

1,229,000

1,078,000

Deferred revenue

4,549,000

4,549,000

4,727,000

$ 0

AstraZeneca | Development milestone

Significant agreements

Transaction price

$ 700,000

AstraZeneca | Target One

Significant agreements

Transaction price

$ 600,000

$ 2,000,000

AstraZeneca | Target Two

Significant agreements

Transaction price

600,000

AstraZeneca | Target Three Research License and Related Services

Significant agreements

Collaboration revenues

400,000

1,000,000

200,000

300,000

AstraZeneca | Commercialization license per candidate

Significant agreements

Customer option payment

8,000,000

AstraZeneca | Development Milestone | Development milestone

Significant agreements

Customer option payment

29,000,000

AstraZeneca | Regulatory Milestone | Regulatory milestone

Significant agreements

Customer option payment

23,000,000

AstraZeneca | Commercial milestone | Commercial milestone

Significant agreements

Customer option payment

$ 110,000,000

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

$ 8,000,000

Transaction price

$ 1,200,000

Deferred revenue

0

0

$ 24,000

AstraZeneca | 2016 Collaboration Agreement | Target One and Target Two Research License and Related Services

Significant agreements

Collaboration revenues

0

$ 200,000

200,000

$ 800,000

AstraZeneca | May 2018 Option Exercise

Significant agreements

Biological Targets | item

4

Option fee for development and exploitation rights

5,000,000

$ 5,000,000

Customer option payment

$ 8,000,000

Number of FTE | employee

2

Transaction price

5,650,000

5,650,000

$ 6,300,000

AstraZeneca | May 2018 Option Exercise | Target Three Research License and Related Services

Significant agreements

Transaction price

650,000

650,000

AstraZeneca | May 2018 Option Exercise | Target 3 Material Right

Significant agreements

Transaction price

1,504,000

1,504,000

AstraZeneca | May 2018 Option Exercise | Target 4 Material Right

Significant agreements

Transaction price

1,204,000

1,204,000

AstraZeneca | May 2018 Option Exercise | Target 5 Material Right

Significant agreements

Transaction price

1,165,000

1,165,000

AstraZeneca | May 2018 Option Exercise | Target 6 Material Right

Significant agreements

Transaction price

$ 1,127,000

$ 1,127,000

Significant agreements - Sanofi

Significant agreements - Sanofi Collaboration Agreement (Details) - USD ($) $ in Thousands	1 Months Ended		3 Months Ended		9 Months Ended
	Mar. 31, 2018	Aug. 31, 2017	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue recognized by non exercising of option			$ 0	$ 0	$ 5,286	$ 0
Revenue from collaborative arrangement			614	1,610	8,520	6,079
Deferred revenue			9,863		9,863		$ 14,635	$ 14,467
Development milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Non refundable payment for services during the BV Bicycle Research Term					4,200
Sanofi
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
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
Total transaction price initially determined		$ 14,200	14,900		14,900
Transaction price		14,200	14,900		14,900
Revenue from collaborative arrangement			0	$ 1,047	6,016	$ 3,258
Deferred revenue			4,506		4,506		$ 9,908	$ 14,467
Sanofi | Sickle Cell Research License and Related Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Non refundable payment for services during the BV Bicycle Research Term	$ 1,400
Total transaction price initially determined		1,405
Transaction price		1,405
Sanofi | Hemophilia Research License and Related Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Non refundable payment for services during the BV Bicycle Research Term	$ 2,800
Total transaction price initially determined		2,811
Transaction price		2,811
Deferred revenue			$ 4,500		4,500
Sanofi | Sickle Cell License Option Material Right
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total transaction price initially determined		5,286
Transaction price		5,286
Revenue recognized by non exercising of option					$ 5,300
Sanofi | Hemophilia License Option Material Right
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Total transaction price initially determined		4,698
Transaction price		4,698
Sanofi | Development milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Option fee payable in order to obtain worldwide development and exploitation rights		5,000
Sanofi | Development milestone | Sickle Cell License Option Material Right
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		47,500
Sanofi | Development milestone | Hemophilia License Option Material Right
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		67,000
Sanofi | Regulatory milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		104,000
Sanofi | Commercial milestone
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Potential milestone payments		$ 55,000

Significant agreements - Oxurio

Significant agreements - Oxurion Collaboration Agreement (Details) $ in Thousands, € in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019EUR (€)	Sep. 30, 2019USD ($)	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Significant agreements
Revenue from collaborative arrangement	$ 614	$ 1,610		$ 8,520	$ 6,079
Deferred revenue						$ 9,863	$ 14,635	$ 14,467
Oxurion
Significant agreements
Threshold period of notice required for termination of agreement			90 days	90 days
Revenue from collaborative arrangement	$ 0	175		$ 0	1,743
Deferred revenue						$ 0	$ 0
Oxurion | Development milestone
Significant agreements
Upfront cash payment | €			€ 1
Potential milestone payments | €			8.3
Revenue under contracts with customer from milestone payment | €			1.8
Revenue from collaborative arrangement		$ 1,200			$ 1,200
Oxurion | Regulatory milestone
Significant agreements
Potential milestone payments | €			€ 16.5

Significant agreements - Dement

Significant agreements - Dementia Discovery Fund Agreement (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	May 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Significant agreements
Collaboration revenues		$ 614	$ 1,610	$ 8,520	$ 6,079
Deferred revenue		9,863		9,863		$ 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		173	$ 0	275	$ 0
Deferred revenue		$ 808		$ 808		$ 0
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 P

Significant agreements - Jazz Pharmaceuticals (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		9 Months Ended
	Oct. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Significant agreements
Collaboration revenues		$ 614	$ 1,610	$ 8,520	$ 6,079
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		$ 0	$ 0	$ 1,000	$ 0

Significant agreements - Summar

Significant agreements - Summary of Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Contract assets
Balance at the beginning of year	$ 0	$ 0
Additions	149	91
Deductions	(103)	(91)
Impact of exchange rates	0	0
Balance at the end of year	46	0
Change in Contract with Customer, Liability [Abstract]
Balance at the beginning of year	14,635	14,467
Additions	1,138	5,350
Deductions	(5,596)	(4,472)
Impact of exchange rates	(314)	(710)
Balance at the end of year	9,863	14,635
AstraZeneca
Change in Contract with Customer, Liability [Abstract]
Balance at the beginning of year	4,727	0
Additions	24	5,350
Deductions	(35)	(466)
Impact of exchange rates	(167)	(157)
Balance at the end of year	4,549	4,727
Sanofi
Change in Contract with Customer, Liability [Abstract]
Balance at the beginning of year	9,908	14,467
Additions	0	0
Deductions	(5,286)	(4,006)
Impact of exchange rates	(116)	(553)
Balance at the end of year	4,506	9,908
Dementia Discovery Fund
Change in Contract with Customer, Liability [Abstract]
Balance at the beginning of year	0
Additions	1,114
Deductions	(275)
Impact of exchange rates	(31)
Balance at the end of year	$ 808	$ 0

Significant agreements - Deferr

Significant agreements - Deferred revenue (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	$ 9,863	$ 14,635	$ 14,467
Sanofi
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	4,506	9,908	14,467
Sanofi | Hemophilia Research License and Related Services
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	4,500
AstraZeneca
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	4,549	4,727	$ 0
AstraZeneca | Target 3, Target 4, Target 5 and Target 6 Material Rights
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	4,500
Dementia Discovery Fund
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue	$ 808	$ 0

Significant agreements - Revenu

Significant agreements - Revenue recognition due to changes in contract assets and liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Significant agreements
Revenue recognized based on proportional performance	$ (173)	$ (1,121)	$ (310)	$ (3,408)
Revenue recognized by non exercising of option	0	0	(5,286)	0
Total revenue recognized	$ (173)	$ (1,121)	$ (5,596)	$ (3,408)

Significant agreements - Cancer

Significant agreements - Cancer Research UK (Details) - USD ($) $ in Millions	Dec. 13, 2016	Sep. 30, 2019	Dec. 31, 2018
Research and development arrangement obligation to repay other parties
Contingent future milestones payments under research and development arrangement	$ 50.9
Other long term liabilities
Research and development arrangement obligation to repay other parties
Liability from research and development		$ 1.4	$ 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%

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Income Taxes
Benefit from income taxes	$ (331)	$ 0	$ (116)	$ (396)

Commitments and Contingencies -

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_2

Commitments and Contingencies - Leases, Office and laboratory space in Lexington, Massachusetts (Details) - Office and laboratory space in Lexington, Massachusetts $ in Millions	1 Months Ended
	Sep. 30, 2017USD ($)
Leases
Security deposit	$ 0.2
Payment under the lease	$ 0.1
Discounted percentage for present value of lease payments	9.00%

Commitments and Contingencies_3

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, 2017USD ($)
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_4

Commitments and Contingencies - Leases, Future minimum lease payments under operating leases and rent expense (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2018
Future minimum lease payments due under operating leases
2019			$ 888
2020			901
2021			915
2022			483
Total			$ 3,187
Total rent expense	$ 300	$ 800

Commitments and Contingencies_5

Commitments and Contingencies - Leases, Components of lease expense (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019USD ($)	Sep. 30, 2019USD ($)
Commitments and Contingencies
Operating lease cost	$ 219	$ 669
Variable lease cost	91	282
Total lease cost	$ 310	$ 951
Weighted-average remaining operating lease term (years)	2 years 10 months 24 days	2 years 10 months 24 days
Weighted-average discount rate	8.50%	8.50%

Commitments and Contingencies_6

Commitments and Contingencies - Leases, Maturities of operating leases (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)
Commitments and Contingencies
2019	$ 434
2020	848
2021	753
2022	443
Present value adjustment	(460)
Total lease liabilities	2,018
Less: current lease liabilities	(602)
Long term lease liabilities	$ 1,416
Maximum days allowed for cancellation of contracts prior written notice	90 days

Commitments and Contingencies_7

Commitments and Contingencies - Founder Royalty arrangements (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	May 28, 2019	May 31, 2017
Related party transactions
Number of securities into which the class of warrant or right may be converted		114,320
Founders and initial investors | Royalty Agreements
Related party transactions
Period of royalty payments agreed under arrangement	10 years
Royalties earned	$ 0
Royalties paid	$ 0
Number of securities into which the class of warrant or right may be converted			200,000

Net loss per share - Basic and

Net loss per share - Basic and diluted net loss per share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Numerator:
Net loss attributable to ordinary shareholders	$ (9,482)	$ (7,692)	$ (26,202)	$ (15,205)
Denominator:
Weighted average ordinary shares outstanding, basic and diluted	17,900,978	433,795	8,734,943	417,223
Net loss per share attributable to ordinary shareholders, basic and diluted	$ (0.53)	$ (17.73)	$ (3)	$ (36.44)

Net loss per share - Securities

Net loss per share - Securities excluded from the diluted per share calculation (Details) - shares	Mar. 07, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	May 28, 2019
Antidilutive securities
Antidilutive securities (in shares)		2,751,595	12,084,507	2,751,595	12,084,507
Remaining warrants exercisable						80,000
Convertible preferred shares (as converted to ordinary shares)
Antidilutive securities
Antidilutive securities (in shares)			9,641,740		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)		114,320	1,347,953	114,320	1,347,953
Percentage of warrants exercise in conjunction with IPO	50.00%
Percentage of warrants expire	50.00%
Remaining warrants exercisable		80,000		80,000
Number of ordinary shares for warrants exercise		114,320		114,320
Restricted shares
Antidilutive securities
Antidilutive securities (in shares)			123,735		123,735
Options to purchase ordinary shares
Antidilutive securities
Antidilutive securities (in shares)		2,637,275	971,079	2,637,275	971,079

Benefit plans (Details)

Benefit plans (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019
United States | 401(k) Plan
Benefit plans
Contributions made	$ 26,000	$ 23,000	$ 100,000
Foreign Plan | U.K. Plan
Benefit plans
Contributions made	$ 100,000		$ 200,000
Percentage of employer contribution on annual base salary			12.00%

Related party transactions (Det

Related party transactions (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
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	$ 0	$ 25,000	$ 50,000	$ 100,000

Geographic information (Details

Geographic information (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)segment	Dec. 31, 2018USD ($)
Geographic information
Number of geographic regions | segment	2
Long lived assets, including operating lease right of use assets	$ 4,329	$ 1,818
United States
Geographic information
Long lived assets, including operating lease right of use assets	2,020	498
United Kingdom
Geographic information
Long lived assets, including operating lease right of use assets	$ 2,309	$ 1,320

Subsequent events (Details)

Subsequent events (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Subsequent events
Deferred revenue recognized		$ 173	$ 1,121	$ 5,596	$ 3,408
Sanofi | Subsequent events
Subsequent events
Deferred revenue recognized	$ 4,500