Property and Equipment (Details) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2018	Dec. 31, 2017
Property, Plant and Equipment, Gross		$ 2,641	$ 2,643
Less accumulated depreciation		(1,470)	(1,189)
Total		1,171	1,454
Research and Development Equipment [Member]
Property, Plant and Equipment, Gross		$ 1,540	1,349
Property, Plant and Equipment, Useful Life		5 years
Office and Computer Equipment [Member]
Property, Plant and Equipment, Gross		$ 730	672
Property, Plant and Equipment, Useful Life		3 years
Autos [Member]
Property, Plant and Equipment, Gross		$ 54	305
Property, Plant and Equipment, Useful Life		5 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Gross		$ 34	34
Property, Plant and Equipment, Useful Life		7 years
Leasehold Improvements [Member]
Property, Plant and Equipment, Gross	[1]	$ 283	283
Construction In Process [Member]
Property, Plant and Equipment, Gross

[1] Shorter of lease term or estimated useful life