Collaboration Agreement - Collaboration Revenue and Collaboration Receivables - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue percentage compared to U.S. XTANDI net sales	50.00%
Collaboration revenue attributable to ex-U.S. XTANDI sales	$ 5,731,000	$ 0
Total collaboration revenue attributable to up-front and milestone payments	19,233,000	8,465,000
Deferred revenue, Current	12,698,000		16,931,000
Development cost-sharing payments [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development cost-sharing payments	15,900,000	7,200,000
Commercial cost sharing-payments [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Commercialization cost-sharing payments	$ 7,600,000	$ 4,800,000
Development cost-sharing payments [Member] | Collaborative agreement [Member] | Medivation Inc [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Share of developing and commercializing XTANDI U.S.	50.00%
Share of developing and commercializing XTANDI ex-U.S.	33.33%
Commercial cost sharing-payments [Member] | Collaborative agreement [Member] | Astellas Pharma Inc. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Share of developing and commercializing XTANDI U.S.	50.00%
Share of developing and commercializing XTANDI ex-U.S.	66.67%