Mundipharma Agreements - Deferred Amounts Related to Mundipharma Agreements (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Business Combination, Separately Recognized Transactions [Line Items]
Deferred development cost liability	$ 3,251	$ 856
Deferred development cost liability, less current portion	15,400	11,377
Mundipharma [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Deferred development cost liability	3,251	856
Deferred development cost liability, less current portion	15,400	11,377
Deferred payment contingency		2,287
Deferred amounts related to the agreements	$ 18,651	$ 14,520