Commitments and Contingencies - Research Collaboration and Licensing Agreements (Details) (USD $)	12 Months Ended					12 Months Ended	1 Months Ended
	Dec. 31, 2013 Agreements with Royalty Provisions	Dec. 31, 2012 Agreements with Royalty Provisions	Dec. 31, 2011 Agreements with Royalty Provisions	Dec. 31, 2013 License agreement with Genentech - EYLEA	Dec. 31, 2012 License agreement with Genentech - EYLEA	Dec. 31, 2013 License agreement with Genentech - ZALTRAP	Jul. 31, 2008 Cellectis Agreement
Research Collaboration and Licensing Arrangements [Line Items]
Royalty rate minimum	1.00%
Royalty rate maximum	16.50%
First payment made or maybe made upon reaching minimum sales target					$ 60,000,000	$ 19,000,000
Cumulative relevant sales minimum sales target				400,000,000		200,000,000
Cumulative sales range, 1st tier minimum				400,000,000		400,000,000
Sales range maximum 1st tier				3,000,000,000		1,000,000,000
Cumulative sales range, 2nd tier minimum				3,000,000,000		1,000,000,000
Royalty payment percentage of cumulative sales within cumulative sales range				4.75%		4.50%
Royalty payment percentage of cumulative sales over range				5.50%		6.50%
Royalty expense	128,100,000	59,500,000	3,200,000
Non-refundable advance payment made under license agreement							$ 12,500,000