Balance Sheet Details - Schedule of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Balance Sheet Related Disclosures [Abstract]
Accounts payable	$ 1,550	$ 2,456
Accrued compensation	3,008	2,804
Accrued research and development	15,883	4,852
Accrued equity issuance costs	3,947	1,143
Other accrued expenses	551	813
Total	$ 24,939	$ 12,068