Balance Sheet Accounts and Supplemental Disclosures - Schedule of Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 8,959	$ 8,157
Less: accumulated depreciation	3,039	2,623
Property and equipment, net	5,920	5,534
Office equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 1,153	1,153
Office equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	3 years
Office equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	7 years
Computer equipment
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	5 years
Total property and equipment	$ 123	123
Software
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	3 years
Total property and equipment	$ 130	116
Lab equipment
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 4,991	4,210
Lab equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	2 years
Lab equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	5 years
Leasehold improvements
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,562	2,540
Leasehold improvements | Minimum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	6 years
Leasehold improvements | Maximum
Property, Plant and Equipment [Line Items]
Estimated Useful Life (in years)	7 years
Construction in process
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 0	$ 15