Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, equipment and software, net
Total property and equipment at cost	$ 9,650	$ 9,365
Less: Accumulated depreciation	(7,682)	(7,635)
Property and equipment	1,968	1,730
Depreciation expense	855	1,010	$ 1,245
Laboratory equipment
Property, equipment and software, net
Total property and equipment at cost	6,725	6,520
Leasehold improvements
Property, equipment and software, net
Total property and equipment at cost	1,906	1,886
Computer equipment and office equipment
Property, equipment and software, net
Total property and equipment at cost	1,019	959
Finance leases
Property, equipment and software, net
Total property and equipment at cost	$ 609	$ 0	$ 429