Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Condensed Consolidated Statements of Operations and Comprehensive Loss
Collaboration revenues	$ 1,785	$ 1,571	$ 3,593	$ 2,700
Operating expenses:
Research and development	11,722	7,958	21,415	15,728
General and administrative	7,340	6,196	15,479	11,197
Total operating expenses	19,062	14,154	36,894	26,925
Loss from operations	(17,277)	(12,583)	(33,301)	(24,225)
Other income (expense):
Interest income	23	371	38	583
Interest expense	(819)		(1,341)
Total other income (expense), net	(796)	371	(1,303)	583
Net loss before income tax provision	(18,073)	(12,212)	(34,604)	(23,642)
Benefit from income taxes	(160)	(97)	(500)	(204)
Net loss	$ (17,913)	$ (12,115)	$ (34,104)	$ (23,438)
Net loss per share, basic	$ (0.74)	$ (0.67)	$ (1.48)	$ (1.30)
Net loss per share, diluted	$ (0.74)	$ (0.67)	$ (1.48)	$ (1.30)
Weighted average ordinary shares outstanding, basic	24,052,168	18,077,770	23,047,745	18,024,314
Weighted average ordinary shares outstanding, diluted	24,052,168	18,077,770	23,047,745	18,024,314
Comprehensives Loss:
Net loss	$ (17,913)	$ (12,115)	$ (34,104)	$ (23,438)
Other comprehensive income (loss):
Foreign currency translation adjustment	(255)	(1)	(313)	(2,185)
Total comprehensive loss	$ (18,168)	$ (12,116)	$ (34,417)	$ (25,623)