Property and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 20,924	$ 20,914
Less: accumulated depreciation and amortization	(19,600)	(19,144)
Property and equipment, net	1,324	1,770
Depreciation and amortization related to property, plant, and equipment	509	563
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 14,924	14,892
Estimated Useful Life (in years)	5 years
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 828	876
Estimated Useful Life (in years)	3 years
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 189	186
Estimated Useful Life (in years)	7 years
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 4,970	4,954
Estimated Useful Life (in years)	7 years
Construction in Progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 13	$ 6