Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Operating expenses:
Research and development	$ 42,580	$ 44,318	$ 84,902	$ 86,145
In process research and development	15	15	35	45
General and administrative	11,277	11,263	23,278	22,609
Total operating expenses	53,872	55,596	108,215	108,799
Loss from operations	(53,872)	(55,596)	(108,215)	(108,799)
Other income (expense)
Interest income	300	141	524	334
Interest expense	(3,481)	(4,834)	(6,948)	(9,614)
Other income	587	457	388	606
Total other expense, net	(2,594)	(4,236)	(6,036)	(8,674)
Net loss	(56,466)	(59,832)	(114,251)	(117,473)
Other comprehensive income (loss):
Foreign currency translation	(138)	162	(146)	(210)
Unrealized loss on marketable securities	(36)	(46)	(413)	(115)
Other comprehensive income (loss)	(174)	116	(559)	(325)
Comprehensive loss	$ (56,640)	$ (59,716)	$ (114,810)	$ (117,798)
Net loss per share, basic (in dollars per share)	$ (0.74)	$ (0.80)	$ (1.50)	$ (1.58)
Net loss per share, diluted (in dollars per share)	$ (0.74)	$ (0.80)	$ (1.50)	$ (1.58)
Weighted average common shares outstanding, basic (in shares)	76,668,162	74,672,882	76,283,564	74,384,805
Weighted average common shares outstanding, diluted (in shares)	76,668,162	74,672,882	76,283,564	74,384,805