Condensed Consolidated Statements of Operations (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Condensed Consolidated Statements of Operations (Unaudited)
License and collaboration revenue - related party	$ 6,217	$ (8,189)	$ 9,864	$ (6,629)
Operating expenses:
Research and development	20,257	19,355	39,025	31,799
General and administrative	4,177	3,863	8,753	7,627
Total operating expenses	24,434	23,218	47,778	39,426
Loss from operations	(18,217)	(31,407)	(37,914)	(46,055)
Interest income	207	641	733	1,372
Interest expense	(209)		(452)
Loss on early repayment of debt	(585)		(585)
Other income (expense), net	512	(37)	22	(39)
Loss before income tax (expense) benefit	(18,292)	(30,803)	(38,196)	(44,722)
Income tax (expense) benefit	(1,129)	1,629	(1,305)	1,445
Net loss	$ (19,421)	$ (29,174)	$ (39,501)	$ (43,277)
Net loss per share, basic and diluted	$ (0.59)	$ (1.18)	$ (1.31)	$ (1.77)
Weighted-average shares used to compute net loss per share, basic and diluted	32,799,691	24,662,779	30,251,805	24,481,186