Accrued Liabilities - Activity Related to Accrued Warranties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Beginning Balance	$ 2,309	$ 2,719	$ 2,364
Provision for warranty expense	3,544	3,597	3,848
Fulfillment of warranty obligations	(3,259)	(4,007)	(3,493)
Ending Balance	$ 2,594	$ 2,309	$ 2,719