Research and Development Collaboration and License Agreements - Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Research and development expenses	$ 24,519,000	$ 18,512,000	$ 18,893,000
Sanofi
Research and Development Arrangement, Contract to Perform for Others [Line Items]
Initial upfront non-refundable payment	35,000,000
Additional non-refundable payment	5,000,000
Development, regulatory and commercial contingent payments	250,000,000
Maximum days to participate in development and promotion of products	90 days
Upfront payment being recognized	40,000,000
Research and development expenses	$ 1,900,000

- Definition

The aggregate costs incurred (1) in a planned search or critical investigation aimed at discovery of new knowledge with the hope that such knowledge will be useful in developing a new product or service, a new process or technique, or in bringing about a significant improvement to an existing product or process; or (2) to translate research findings or other knowledge into a plan or design for a new product or process or for a significant improvement to an existing product or process whether intended for sale or the entity's use, during the reporting period charged to research and development projects, including the costs of developing computer software up to the point in time of achieving technological feasibility, and costs allocated in accounting for a business combination to in-process projects deemed to have no alternative future use.

+ References+ Details