Property and Equipment (Tables)

12 Months Ended

Dec. 31, 2017

Property, Plant and Equipment [Abstract]

Schedule of Property and Equipment

Property and equipment are stated at cost and depreciated using the straight-line method over the estimated useful lives of the related assets and consist of the following (in thousands):

	At December 31,
	2017			2016
Equipment (useful life 3 - 15 years)	$	1,557		$	2,231
Tooling (useful life 2 - 5 years)	371			863
Vehicles (useful life 5 years)	47			39
Furniture and fixtures (useful life 5 years)	137			170
Computer software (useful life 3 years)	1,043			977
Leasehold improvements (the shorter of useful life or lease life)	201			256
Construction in progress	55			154
Property and equipment at cost	3,411			4,690
Less: accumulated depreciation	(2,314		)	(2,365		)
Property and equipment, net	$	1,097		$	2,325