Certain Balance Sheet Accounts - Property and Equipment, Net (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Total cost	$ 11,361		$ 11,361		$ 10,764
Less accumulated depreciation and amortization	(9,440)		(9,440)		(9,033)
Total property and equipment, net	1,921		1,921		1,731
Depreciation and amortization	200	$ 400	469	$ 745
Finance leases
Property, Plant and Equipment [Line Items]
Total cost	6,537		6,537		5,979
Laboratory equipment
Property, Plant and Equipment [Line Items]
Total cost	3,123		3,123		3,091
Computer equipment
Property, Plant and Equipment [Line Items]
Total cost	1,076		1,076		1,069
Office equipment and furniture
Property, Plant and Equipment [Line Items]
Total cost	$ 625		$ 625		$ 625