Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2023	Dec. 31, 2022
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 1,461	$ 1,392
Less: accumulated depreciation	(1,349)	(1,316)
Property and equipment, net	$ 112	76
Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	2 years
Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	15 years
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 1,061	1,061
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	15 years
Tooling
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 190	190
Tooling | Minimum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	2 years
Tooling | Maximum
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Vehicles
Property, Plant and Equipment [Line Items]
Property and equipment, useful life (in years)	5 years
Property and equipment, gross	$ 41	0
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	141	141
Construction in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 28	$ 0