Collaboration Agreements (Bayer HealthCare LLC) (Details) - USD ($) $ in Thousands		1 Months Ended		9 Months Ended	12 Months Ended
	Mar. 31, 2016	Aug. 31, 2007	Oct. 31, 2006	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Collaboration Agreements [Line Items]
Accounts receivable from Bayer HealthCare					$ 175,263	$ 162,152
Deferred revenue, current portion					231,664	153,487
Other Collaboration Revenue					744,270	580,488	$ 495,555
Collaboration Agreement with Bayer HealthCare LLC
Collaboration Agreement [Abstract]
Contingent reimbursement obligation					256,000
Collaboration Agreements [Line Items]
Deferred Revenue, Additions		$ 20,000	$ 75,000
Net profit (loss) from commercialization of products under collaboration agreement					649,232	466,667	301,302
Revenue Recognition, Milestone Method, Revenue Recognized					0	15,000	105,000
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned					9,010	8,887	23,383
Other Collaboration Revenue					710,769	560,020	482,075
Contracts Revenue					52,527	69,466	52,390
EYLEA
Collaboration Agreements [Line Items]
Deferred revenue, current portion					62,373	46,694
PDGFR-beta outside the US
Collaboration Agreements [Line Items]
Deferred Revenue, Additions							2,500
Deferred revenue, current portion					0	9,522
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned					10,291	10,075	2,848
Other Collaboration Revenue					19,867	20,468	13,480
Contracts Revenue					$ 9,576	10,393	10,632
Percentage of global development cost to be paid by the collaboration partner under the collaboration					25.00%
Percentage of development cost for the territory outside the United States to be paid for under the collaboration					50.00%
Ang2
Collaboration Agreements [Line Items]
Deferred revenue, current portion					$ 45,739	0
Research and Development Arrangement, Contract to Perform for Others, Compensation Earned					8,036	0	0
Other Collaboration Revenue					13,634	0	0
Contracts Revenue					5,598	$ 0	$ 0
Ang2 Antibody [Member]
Collaboration Agreements [Line Items]
Deferred Revenue, Additions	$ 50,000
Percentage of global development cost to be paid by the collaboration partner under the collaboration	25.00%
Percentage of development cost for the territory outside the United States to be paid for under the collaboration	50.00%
Future development milestone payment the Company is eligible to receive					$ 80,000
Minimum | Collaboration Agreement with Bayer HealthCare LLC
Collaboration Agreements [Line Items]
Revenue based on percentage of annual sales in Japan				33.50%
Maximum | Collaboration Agreement with Bayer HealthCare LLC
Collaboration Agreements [Line Items]
Revenue based on percentage of annual sales in Japan				40.00%