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Property and Equipment - Schedule of Property and Equipment (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Finance lease right-of-use asset	$ 13		$ 13		$ 13
Property and equipment at cost	3,295		3,295		3,084
Less: accumulated depreciation	(2,764)		(2,764)		(2,664)
Property and equipment, net	531		531		420
Depreciation	53	$ 46	100	$ 92
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment, gross	1,301		$ 1,301		1,281
Equipment \| Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)			3 years
Equipment \| Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)			15 years
Tooling
Property, Plant and Equipment [Line Items]
Property and equipment, gross	265		$ 265		240
Tooling \| Minimum
Property, Plant and Equipment [Line Items]
Useful life (in years)			2 years
Tooling \| Maximum
Property, Plant and Equipment [Line Items]
Useful life (in years)			5 years
Vehicles
Property, Plant and Equipment [Line Items]
Useful life (in years)			5 years
Property and equipment, gross	83		$ 83		47
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life (in years)			5 years
Property and equipment, gross	137		$ 137		137
Computer software
Property, Plant and Equipment [Line Items]
Useful life (in years)			3 years
Property and equipment, gross	1,179		$ 1,179		1,057
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment, gross	169		$ 169		169
UV - Robots
Property, Plant and Equipment [Line Items]
Useful life (in years)			5 years
Property and equipment, gross	64		$ 64		0
Projects in progress
Property, Plant and Equipment [Line Items]
Property and equipment, gross	$ 84		$ 84		$ 140