Description of Business - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013 Person Country	Dec. 31, 2012
Organization And Description Of Business [Line Items]
Number of countries in which XTANDi is approved for the post-docetaxel indication	35
Approximate number of patients in Prevail clinical trial	1,700
Cumulative net losses	$ (334,161,000)	$ (291,548,000)
Milestone payments received	78,000,000
Development milestone payments [Member] | Astellas Pharma Inc. [Member]
Organization And Description Of Business [Line Items]
Milestone payments received	78,000,000
Remaining future milestone payments	257,000,000
Sales milestone payments [Member] | Astellas Pharma Inc. [Member]
Organization And Description Of Business [Line Items]
Accrued milestone payments	25,000,000
Remaining development future sales milestone payments the Company is eligible to receive	$ 295,000,000
2.625% convertible senior notes due 2017 [Member]
Organization And Description Of Business [Line Items]
Debt instrument, interest rate	2.625%	2.625%