Property and Equipment and Assets Held For Sale (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 4,298		$ 4,690
Less: accumulated depreciation	(2,537)		(2,365)
Property and equipment, net	1,761		2,325
Depreciation	177	$ 151
Equipment
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 1,825		2,231
Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	15 years
Tooling
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 866		863
Tooling | Minimum
Property, Plant and Equipment [Line Items]
Useful life	2 years
Tooling | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Vehicles
Property, Plant and Equipment [Line Items]
Useful life	5 years
Property and equipment at cost	$ 86		39
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Useful life	5 years
Property and equipment at cost	$ 170		170
Computer software
Property, Plant and Equipment [Line Items]
Useful life	3 years
Property and equipment at cost	$ 977		977
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property and equipment at cost	262		256
Projects in progress
Property, Plant and Equipment [Line Items]
Property and equipment at cost	$ 112		154
Discontinued Operations, Held-for-sale | Equipment
Property, Plant and Equipment [Line Items]
Property and equipment at cost			$ 410