Inventory - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017	Jun. 30, 2016
Inventory [Line Items]
Inventory write-downs		$ 71,255	$ 29,725
Cost of Revenues [Member]
Inventory [Line Items]
Inventory write-downs	$ 45,800	$ 66,800