Accumulated Other Comprehensive Income - Amounts Reclassified out of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	$ 387,763	$ 372,845	$ 788,508	$ 746,292
Total gain (loss) on cash flow hedges	(41,354)	(25,263)	(95,305)	(69,635)
Net product revenues
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	379,075	367,786	773,558	736,885
Amount Reclassified from AOCI Gain (Loss) | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total gain (loss) on cash flow hedges	3,512	(2,659)	4,478	(8,444)
Amount Reclassified from AOCI Gain (Loss) | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Forward contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	(768)	1,403	(497)	3,264
Amount Reclassified from AOCI Gain (Loss) | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent | Net product revenues | Forward contracts
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net product revenues	$ 4,280	$ (4,062)	$ 4,975	$ (11,708)