Schedule II Valuation and Qualifying Accounts - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
SEC Schedule, 12-09, Allowance, Credit Loss [Member]
Balance at Beginning of Period	$ 213	$ 146
Expense (Recovery)	20	68
Deductions		(1)
Balance at End of Period	233	213
SEC Schedule, 12-09, Reserve, Warranty [Member]
Balance at Beginning of Period	233	125
Expense (Recovery)	452	209
Deductions	(339)	(101)
Balance at End of Period	$ 346	$ 233