Inventories, Net and Significant Suppliers - Changes in Reserve for Excess and Obsolete Inventory (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Schedule of Reserve for Excess and Obsolete Inventory [Rollforward]
Balance at beginning of period	$ 4,288	$ 4,205
Additions charged to costs and expenses	4,564	1,218
Sell through	(680)	(576)
(Write-offs)/Foreign exchange effects	(635)	(640)
Balance at end of period	7,537	4,207
Inventory written-off and scrapped during production	$ 500	$ 200