Deferred Revenue and Remaining Performance Obligations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Disaggregation of Revenue [Line Items]
Deferred revenue and income	$ 338		$ 338		$ 271
Revenues recognized included in contract liabilities balances	100	$ 200	200	$ 300
Revenue expected to be recognized from remaining performance obligations	8,600		$ 8,600
Contact period			The remaining balance relates to executed service contracts that begin as warranty periods expire. These service contracts typically provide for four-year terms and revenue is recognized on a straight-line basis.
Products and services not yet delivered
Disaggregation of Revenue [Line Items]
Deferred revenue and income	$ 338		$ 338		$ 271