Collaboration Agreement - Schedule of Collaboration Revenue (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Collaboration revenue	$ 377,748	$ 260,665	$ 175,657	$ 129,188	$ 274,730	$ 200,478	$ 148,090	$ 87,189	$ 943,258	$ 710,487	$ 272,942
Collaborative agreement [Member] | XTANDI [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Related to upfront and milestone payments									247,822	321,109	70,396
Collaboration revenue									943,258	710,487	272,942
Collaborative agreement [Member] | U.S. [Member] | XTANDI [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Related to XTANDI net sales									575,658	339,902	196,208
Collaborative agreement [Member] | ex-U.S. [Member] | XTANDI [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Related to XTANDI net sales									$ 119,778	$ 49,476	$ 6,338