License and Collaboration Agreements - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	9 Months Ended				0 Months Ended					9 Months Ended	1 Months Ended	2 Months Ended			1 Months Ended	9 Months Ended		12 Months Ended	1 Months Ended	9 Months Ended			3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 MOVANTIK [Member] US and EU Commercial Launch [Member]	Sep. 30, 2014 MOVANTIK [Member] United States [Member] US and EU Commercial Launch [Member]	Sep. 30, 2014 MOVANTIK [Member] European Union [Member] US and EU Commercial Launch [Member]	Sep. 16, 2014 AstraZeneca AB [Member] MOVANTIK [Member]	Sep. 30, 2014 AstraZeneca AB [Member] MOVANTIK [Member]	Sep. 16, 2014 AstraZeneca AB [Member] MOVANTIK [Member]	Sep. 16, 2014 AstraZeneca AB [Member] MOVANTIK [Member] Pre-approval Cardiovascular Safety Study Not Required [Member]	Sep. 30, 2014 AstraZeneca AB [Member] Movantik Fixed-dose Combination Program [Member]	Sep. 30, 2014 Roche [Member] MIRCERA [Member]	Feb. 29, 2012 Roche [Member] MIRCERA [Member] Performance-based Milestone Payments [Member]	Feb. 29, 2012 Roche [Member] MIRCERA [Member] Upfront Payment Arrangement in 2007 [Member]	Sep. 30, 2014 Roche [Member] PEGASYS [Member]	Sep. 30, 2014 Roche [Member] PEGASYS and MIRCERA [Member]	Jun. 30, 2013 Bayer Healthcare LLC [Member]	Sep. 30, 2014 Bayer Healthcare LLC [Member]	Sep. 30, 2014 Bayer Healthcare LLC [Member] Performance-based Milestone Payments [Member]	Dec. 31, 2007 Bayer Healthcare LLC [Member] Upfront Payment Arrangement in 2007 [Member]	Jun. 30, 2014 Ophthotech Corporation [Member] Fovista [Member]	Sep. 30, 2014 Ophthotech Corporation [Member] Fovista [Member]	Sep. 30, 2014 Other [Member]	Sep. 30, 2014 Amgen, Inc. [Member]	Sep. 30, 2014 Baxter Healthcare [Member] BAX 855 (Hemophilia) [Member]	Sep. 30, 2014 Baxter Healthcare [Member] BAX 855 (Hemophilia) [Member]
Deferred Revenue Arrangement [Line Items]
Potential aggregate future additional payments for development milestones	$ 138.3															$ 50.0				$ 9.5	$ 61.8			$ 20.0
Contingent payments receivable based on development events regulatory to be pursued and completed solely by others		140.0	100.0	40.0		140.0		35.0	75.0
Received upfront and milestone payments					70.00						22.00	5.00					30.00	40.00	19.75
Potential reduction in U.S. royalty rate for repayment					2.00%
Percentage of post approval study costs to repay					33.00%
Maximum potential reduction in royalties							35.0
Deferred revenue										12.1			6.4	5.1		21.2				19.3		30.4	0	0
Consideration received for product delivered in 2013										18.6
Performance milestone payment to Bayer															10.0
Development milestones achieved																							8.0
Royalty expiration period																				10 years
Milestone payment received from transfers of manufacturing technology																					$ 9.0