Deferred Revenue, Income and Remaining Performance Obligations (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	Jan. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Deferred Revenue Disclosure [Abstract]
Products and services not yet delivered		$ 117	$ 71
Arizona Commerce Authority grant		0	1,000
Deferred revenue and income		117	$ 1,071
Revenue recognized	$ 1,000
Revenues recognized included in contract liabilities balances		21
Revenue expected to be recognized from remaining performance obligations		$ 737
Contact period		4 years