Description of Business - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015 Product
XTANDI [Member]
Organization And Description Of Business [Line Items]
Number of commercial products	1
Collaborative agreement [Member] | Astellas Pharma Inc. [Member]
Organization And Description Of Business [Line Items]
Range of percentage rates for royalties received on ex-U.S. net sales, as defined by collaboration agreement	Low teens to the low twenties