Collaboration Agreements (Substantive Development Milestone Payments Eligible To Receive Under Astellas Collaboration Agreement) (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	$ 7
Deferred revenue additions related to development milestones	58
4th Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | The U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement		[1],[2]
4th Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | The First Major Country In Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement		[1],[2]
4th Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	5	[1]
4th Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | The U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement		[1],[2]
4th Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | The First Major Country In Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	15	[1]
4th Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	15	[1]
3rd Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | The U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	10	[3]
3rd Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | The First Major Country In Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	5	[3]
3rd Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	5	[3]
3rd Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | The U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	30	[3]
3rd Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | The First Major Country In Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	15	[3]
3rd Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	15	[3]
2nd Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | The U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	15	[4],[5]
2nd Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | The First Major Country In Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	10	[4],[5]
2nd Line Prostate Cancer Patients [Member] | First Acceptance For Filing Of A Marketing Application [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	10	[4],[5]
2nd Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | The U.S. [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	60	[4],[5]
2nd Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | The First Major Country In Europe [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	30	[4],[5]
2nd Line Prostate Cancer Patients [Member] | First Approval Of A Marketing Application [Member] | Japan [Member]
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Development milestone payments eligibility to receive under Collaboration agreement	$ 30	[4],[5]

[1] Defined as prostate cancer patients who meet each of the following three criteria: (a) prior treatment failure on either (i) one or more luteinizing hormone-releasing hormone, or LHRH, analog drugs or (ii) surgical castration; (b) prior treatment failure on one or more androgen receptor antagonist drugs; and (c) prior treatment failure on chemotherapy.

[2] These milestone payments totaling $58.0 million have been previously earned and the related payments have been received.

[3] Defined as prostate cancer patients who meet each of the following three criteria: (a) prior treatment failure on either (i) one or more LHRH analog drugs or (ii) surgical castration; (b) prior treatment failure on one or more androgen receptor antagonist drugs; and (c) no prior exposure to chemotherapy for prostate cancer.

[4] Defined as prostate cancer patients who meet each of the following two criteria: (a) prior treatment failure on either (i) one or more LHRH analog drugs or (ii) surgical castration; and (b) no prior treatment failure on one or more androgen receptor antagonist drugs.

[5] An additional milestone payment of $7 million is payable upon the first to occur of: (a) first approval of a marketing application in the United States with a label encompassing 2nd line prostate cancer patients; (b) first approval of a marketing application in the first major country in Europe with a label encompassing 2nd line prostate cancer patients; (c) first approval of a marketing application in Japan with a label encompassing 2nd line prostate cancer patients; or (d) first patient dosed in a Phase 3 clinical trial other than the PREVAIL trial that is designed specifically to support receipt of marketing approval in 2nd line patients.