Product Warranty (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Product Warranty
Product warranty period	1 year
Changes in standard product warranty liability
Balance at the beginning of the period	$ 3,555	$ 1,526
Warranties issued during the period	921	1,080
Settlements made during the period	(1,306)	(566)
Changes in estimate of liability for pre-existing warranties during the period	365	123
Balance at the end of the period	3,535	2,163
Product warranty classification
Amount classified as current			$ 3,288	$ 3,363	$ 1,909
Amount classified within other long-term liabilities			247		254
Total warranty liability	$ 3,555	$ 1,526	$ 3,535	$ 3,555	$ 2,163