Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Loss Contingencies [Line Items]
Royalty expense	$ 3,400,000	$ 4,100,000	$ 2,900,000
Purchase commitments related to contract manufacturing, clinical development and certain other items	16,900,000
Indemnification Obligation [Member]
Loss Contingencies [Line Items]
Indemnification Obligations, liabilities	0	0
Securities Related Claims [Member]
Loss Contingencies [Line Items]
Obligations under Director and Officer Indemnifications per incident	1,000,000
Non-Securities Related Claims [Member]
Loss Contingencies [Line Items]
Obligations under Director and Officer Indemnifications per incident	500,000
Merger and Acquisition Related Claims [Member]
Loss Contingencies [Line Items]
Obligations under Director and Officer Indemnifications per incident	$ 1,500,000