Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (16,191)	$ (11,324)
Adjustments to reconcile net loss to net cash used in operating activities:
Share-based compensation expense	3,821	2,121
Depreciation and amortization	325	305
Non-cash interest	93
Changes in operating assets and liabilities:
Accounts receivable	3,520	(846)
Research and development incentives receivable	(2,277)	(2,097)
Prepaid expenses and other current assets	(922)	347
Operating lease right-of-use assets	(2,434)	187
Other assets	(353)	(215)
Accounts payable	(304)	2,702
Accrued expenses and other current liabilities	(1,858)	(464)
Operating lease liabilities	2,466	191
Deferred revenue	236	30,103
Other long-term liabilities	171	152
Net cash (used in) provided by operating activities	(13,707)	21,162
Cash used in investing activities:
Purchases of property and equipment	(623)	(320)
Net cash used in investing activities	(623)	(320)
Cash flows from financing activities:
Proceeds from the issuance of ADSs, net of issuance costs	58,775
Proceeds from the exercise of share options and sale of ordinary shares	284	2
Proceeds from issuance of debt	15,000
Net cash provided by financing activities	74,059	2
Effect of exchange rate changes on cash	182	(3,324)
Net increase in cash	59,911	17,520
Cash at beginning of period	135,990	92,117
Cash at end of period	195,901	109,637
Supplemental disclosure of cash flow information
Cash paid for interest	429
Cash paid for income taxes		11
Cash paid for amounts included in the measurement of operating lease liabilities	199
Purchases of property and equipment included in accounts payable and accrued expenses	$ 76	$ 71