Commitments and Contingencies - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loss Contingencies [Line Items]
Royalty expense	$ 2,900,000	$ 1,800,000	$ 2,200,000
Purchase commitments related to contract manufacturing, clinical development and certain other items	14,600,000
Securities related claims [Member]
Loss Contingencies [Line Items]
Obligations under Director and Officer Indemnifications per incident	500,000
Non-securities related claims [Member]
Loss Contingencies [Line Items]
Obligations under Director and Officer Indemnifications per incident	$ 150,000