Effect of Derivative Instruments (Detail) - Forward Foreign Currency Exchange Contracts - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Derivatives Designated As Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in accumulated other comprehensive loss	[1]	$ 23,582	$ (19,165)	$ 14,356	$ (23,364)
Net gain (loss) reclassified from accumulated other comprehensive income (loss) into earnings	[2]	(2,659)	695	(8,444)	3,211
Net gain (loss) recognized in net loss	[3]	(4,238)	5,373	2,985	5,631
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Net gain (loss) recognized in net loss	[4]	$ 2,700	$ 826	$ 2,322	$ 1,706

[1] Net change in the fair value of the effective portion classified as accumulated other comprehensive loss.

[2] Effective portion classified as Net Product Revenues and Operating expenses.

[3] Classified as Operating expenses.

[4] Ineffective portion and amount excluded from effectiveness testing classified as Operating expenses.