Collaboration Revenue (Details) (USD $)	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 Antibody Collaboration	Sep. 30, 2012 Antibody Collaboration	Sep. 30, 2013 Antibody Collaboration	Sep. 30, 2012 Antibody Collaboration	Sep. 30, 2013 VelociGene Agreement	Sep. 30, 2012 VelociGene Agreement	Sep. 30, 2013 VelociGene Agreement	Sep. 30, 2012 VelociGene Agreement	Sep. 30, 2013 Collaboration Agreement with Sanofi ZALTRAP	Sep. 30, 2012 Collaboration Agreement with Sanofi ZALTRAP	Sep. 30, 2013 Collaboration Agreement with Sanofi ZALTRAP	Sep. 30, 2012 Collaboration Agreement with Sanofi ZALTRAP	Sep. 30, 2013 Collaboration Agreement with Bayer HealthCare LLC	Sep. 30, 2012 Collaboration Agreement with Bayer HealthCare LLC	Sep. 30, 2013 Collaboration Agreement with Bayer HealthCare LLC	Sep. 30, 2012 Collaboration Agreement with Bayer HealthCare LLC	Sep. 30, 2013 Collaboration Agreement with Bayer HealthCare LLC EYLEA	Sep. 30, 2012 Collaboration Agreement with Bayer HealthCare LLC EYLEA	Sep. 30, 2013 Collaboration Agreement with Bayer HealthCare LLC EYLEA	Sep. 30, 2012 Collaboration Agreement with Bayer HealthCare LLC EYLEA	Jun. 30, 2013 Ang2	Sep. 30, 2013 Ang2	Jun. 30, 2013 PDGF	Sep. 30, 2013 PDGF	Sep. 30, 2013 Receipt of marketing approval Collaboration Agreement with Bayer HealthCare LLC	Sep. 30, 2013 Sales achievement 1st tier Collaboration Agreement with Bayer HealthCare LLC	Sep. 30, 2013 Sales achievement 2nd tier Collaboration Agreement with Bayer HealthCare LLC
Research Collaboration and Licensing Arrangements [Line Items]
Number of up-front payments							2
Net profit (loss) from commercialization of products under collaboration agreement													$ (6,575,000)	$ (7,390,000)	$ (22,581,000)	$ (19,525,000)
Revenue Recognition, Milestone Method, Revenue Recognized														50,000,000		50,000,000	45,000,000	15,000,000	45,000,000	15,000,000									15,000,000	15,000,000	15,000,000
Maximum amount of substantive milestone payments that may be received in major market countries outside the U S																			10,000,000
Starting specified levels of annual sales at which sales milestone payments may be received, 1st tier																			200,000,000
Number of sales milestones																			2
Starting specified levels of annual sales at which sales milestone payments may be received, 2nd tier																			300,000,000
Period for achieving sales target for milestone payment, rolling basis																			12 months
Number of families of novel antibodies							2
Net profit from commercialization of products under collaboration agreement																					31,769,000		57,186,000
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned					134,432,000	94,903,000	341,952,000	263,504,000					2,557,000	2,079,000	7,955,000	9,124,000					4,844,000	9,724,000	14,482,000	27,377,000
Research and Development Asset Acquired Other than Through Business Combination, Written-off							(20,000,000)																		(10,000,000)	(10,000,000)	(10,000,000)	(10,000,000)
Reimbursement of commercial expenses																					4,993,000		11,995,000
Recognition of Deferred Revenue					2,162,000	2,162,000	6,486,000	6,475,000	399,000	399,000	1,197,000	1,197,000	1,384,000	2,889,000	4,152,000	8,260,000	1,977,000	1,977,000	5,931,000	5,931,000
Sanofi collaboration revenue	134,359,000	145,042,000	319,161,000	319,035,000	136,993,000	97,464,000	329,635,000	271,176,000					(2,634,000)	47,578,000	(10,474,000)	47,859,000
Bayer HealthCare collaboration revenue	88,583,000	26,701,000	134,594,000	48,308,000
Substantive Milestone Payments																									5,000,000		40,000,000
Maximum amount of sales milestone payments if total sales achieve specific levels																			105,000,000
Maximum levels of annual sales for which sales milestone payments may be received																			$ 1,000,000,000