Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Total property and equipment	$ 2,961	$ 2,842
Less accumulated depreciation and amortization	(2,640)	(2,481)
Property and equipment, net	321	361
Laboratory equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	1,838	1,702
Computer Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	304	302
Office Furniture And Equipment [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	217	217
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment	602	596
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Total property and equipment		$ 25