Commitments and Contingencies Warranty activity (Details) - Accrued Liabilities [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Product Warranty Liability [Line Items]
Standard Product Warranty Accrual	$ 1,541	$ 853	$ 1,541	$ 853	$ 1,503	$ 1,210	$ 717	$ 474
Standard Product Warranty Accrual, Warranties Issued	362	341	1,116	859
Standard Product Warranty Accrual, Payments	$ (324)	$ (205)	$ (785)	$ (480)