Description of Business - Additional Information (Detail)	6 Months Ended
	Jun. 30, 2016 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