Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Consolidated Statements of Operations [Abstract]
Revenue	$ 0	$ 0
Operating expenses:
Research and development	30,794	28,309
General and administrative	11,770	10,913
Total operating expenses	42,564	39,222
Loss from operations	(42,564)	(39,222)
Research and development incentives	0	500
Interest expense	(464)	(1,729)
Interest and other income, net	623	911
Amortization of premium on investments - net	(577)	(639)
Net loss	$ (42,982)	$ (40,179)
Net loss per share attributable to common stockholders - basic (in dollars per share)	$ (0.67)	$ (0.65)
Net loss per share attributable to common stockholders - diluted (in dollars per share)	$ (0.67)	$ (0.65)
Weighted-average common shares outstanding - basic (in shares)	64,509,721	61,574,405
Weighted-average common shares outstanding - diluted (in shares)	64,509,721	61,574,405