Derivative Instruments and Hedging Strategies - Summary of Impact of Gains and Losses from Derivatives Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Net product revenues	$ 461,097	$ 391,706	$ 1,249,605	$ 1,137,998
Operating expenses as reported	457,087	407,447	1,340,900	1,223,374
Derivatives Designated As Hedging Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount of Gain (Loss) Recognized in Other Comprehensive Income	23,973		35,431
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gains (Losses) Recognized in Earnings	(1,286)		(5,182)
Operating Expense | Derivatives Designated As Hedging Instruments | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedging Gains (Losses) Reclassified into Earnings	(1,388)		(1,885)
Net product revenues
Derivative Instruments, Gain (Loss) [Line Items]
Net product revenues	450,900	$ 386,320	1,224,458	$ 1,123,205
Net product revenues | Derivatives Designated As Hedging Instruments | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Derivative Instruments, Gain (Loss) [Line Items]
Cash Flow Hedging Gains (Losses) Reclassified into Earnings	$ 6,196		$ 11,171