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)	$ (3.00)	$ (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)