Commitments and Contingencies Warranty activity (Details) - Accrued Liabilities [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Product Warranty Liability [Line Items]
Standard Product Warranty Accrual	$ 1,503	$ 717	$ 1,503	$ 717	$ 1,331	$ 1,210	$ 514	$ 474
Standard Product Warranty Accrual, Warranties Issued	443	296	754	490
Standard Product Warranty Accrual, Payments	$ (271)	$ (93)	$ (461)	$ (247)