Condensed Consolidated Statements of Operations and Comprehensive Loss - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Income Statement [Abstract]
Collaboration revenue		$ 300
Operating expenses:
Research and development	$ 67,150	45,118	$ 53,249
General and administrative	27,435	20,123	13,743
Total operating expenses	94,585	65,241	66,992
Loss from operations	(94,585)	(64,941)	(66,992)
Other expense (income), net:
Changes in fair value of warrant liabilities	0	16,240	20,926
Other expense (income), net	77	(421)	517
Total other expense (income), net	77	15,819	21,443
Loss before provision for (benefit from) income taxes, net	(94,662)	(80,760)	(88,435)
Provision for (benefit from) income taxes, net	(3)	142	(160)
Net loss and comprehensive loss	$ (94,659)	$ (80,902)	$ (88,275)
Net loss per common share, basic and diluted	$ (7.14)	$ (7.70)	$ (30.30)
Weighted-average shares used in computing net loss per common share, basic and diluted	13,252,605	10,506,739	2,913,487