Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Condensed Consolidated Statements of Operations and Comprehensive Loss
Collaboration revenues	$ 3,842	$ 614	$ 6,542	$ 8,520
Operating expenses:
Research and development	7,363	6,078	23,091	18,891
General and administrative	7,154	4,789	18,351	11,164
Total operating expenses	14,517	10,867	41,442	30,055
Loss from operations	(10,675)	(10,253)	(34,900)	(21,535)
Other income (expense):
Interest and other income, net	72	440	655	594
Other expense, net				(5,377)
Total other income (expense), net	72	440	655	(4,783)
Net loss before income tax provision	(10,603)	(9,813)	(34,245)	(26,318)
Benefit from income taxes	(465)	(331)	(668)	(116)
Net loss	(10,138)	(9,482)	(33,577)	(26,202)
Net loss attributable to ordinary shareholders	$ (10,138)	$ (9,482)	$ (33,577)	$ (26,202)
Net loss per share attributable to ordinary shareholders, basic and diluted	$ (0.52)	$ (0.53)	$ (1.81)	$ (3.00)
Weighted average ordinary shares outstanding, basic and diluted	19,426,833	17,900,978	18,504,013	8,734,943
Comprehensives Loss:
Net loss	$ (10,138)	$ (9,482)	$ (33,577)	$ (26,202)
Other comprehensive income (loss):
Foreign currency translation adjustment	743	(424)	(1,442)	(856)
Total comprehensive loss	$ (9,395)	$ (9,906)	$ (35,019)	$ (27,058)