Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 7,903	$ 7,837
Accumulated Amortization	(4,463)	(4,352)
Net Carrying Value	$ 3,440	$ 3,485
Weighted Average Useful Life	7 years 7 months 6 days	8 years
Developed technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,900	$ 3,900
Accumulated Amortization	(3,900)	(3,900)
Net Carrying Value	0	0
Vision development costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,929	2,929
Accumulated Amortization	(544)	(452)
Net Carrying Value	$ 2,385	$ 2,477
Weighted Average Useful Life	8 years	8 years
Software development in process costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 846	$ 1,008
Accumulated Amortization	0	0
Net Carrying Value	846	$ 1,008
Wrong Way development costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	228
Accumulated Amortization	(19)
Net Carrying Value	$ 209
Weighted Average Useful Life	2 years