Stockholders' Equity - Schedule of Stock-Based Compensation Expense (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	$ 11,181	$ 8,131	$ 20,842	$ 16,427
R&D expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	4,503	3,619	8,625	7,437
SG&A expense [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Share-based compensation	$ 6,678	$ 4,512	$ 12,217	$ 8,990