Consolidated Statements of Operations and Comprehensive Loss - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Operating expenses:
Research and development	$ 83,114	$ 87,236
General and administrative	35,727	32,992
Total operating expenses	118,841	120,228
Loss from operations	(118,841)	(120,228)
Other (expense) income:
Interest (expense) income, net	(224)	719
Other expense, net	(61)	(203)
Total other (expense) income, net	(285)	516
Net loss	(119,126)	(119,712)
Comprehensive loss	$ (119,126)	$ (119,712)
Net loss per share —basic and diluted	$ (2.78)	$ (3.31)
Weighted-average number of common shares outstanding—basic and diluted	42,854	36,206