Commitments and Contingencies - Summary of Warranty Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance - Beginning of the year	$ 5,552	$ 7,580
Provision for new warranty claims	3,461	1,798
Change in provision for preexisting warranty claims	(1,065)	389
Deduction for payments made	(4,579)	(3,819)
Currency translation adjustment	121	(396)
Balance - End of year	$ 3,490	$ 5,552