Balance Sheet Components - Summary of Property and Equipment, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property Plant And Equipment [Line Items]
Total property and equipment	$ 8,165	$ 7,158
Less: Accumulated depreciation and amortization	(3,894)	(2,516)
Property and equipment, net	4,271	4,642
Laboratory Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 4,793	4,034
Property and equipment net, useful life	5 years
Computer Equipment
Property Plant And Equipment [Line Items]
Total property and equipment	$ 117	117
Property and equipment net, useful life	3 years
Software
Property Plant And Equipment [Line Items]
Total property and equipment	$ 118	118
Property and equipment net, useful life	3 years
Leasehold Improvements
Property Plant And Equipment [Line Items]
Total property and equipment	$ 2,716	2,581
Property and equipment net, useful life	Shorter of useful life or lease term
Furniture and Fixtures
Property Plant And Equipment [Line Items]
Total property and equipment	$ 421	$ 308
Property and equipment net, useful life	5 years