Legal Matters (Details) (Pending litigation, USD $)	6 Months Ended		0 Months Ended			0 Months Ended	6 Months Ended
	Jun. 30, 2013 License agreement with Genentech - EYLEA	Dec. 31, 2012 License agreement with Genentech - EYLEA United States	Sep. 25, 2012 First Davis Smyth Case [Member] claim	Sep. 21, 2012 First Davis Smyth Case [Member] claim	Jan. 17, 2012 First Davis Smyth Case [Member] claim	Dec. 23, 2011 Second Davis Smyth Case [Member] claim	Jun. 30, 2013 License agreement with Genentech - ZALTRAP Global	May 17, 2013 License agreement with Genentech - ZALTRAP Global
Loss Contingencies [Line Items]
Payment made or may be made upon reaching minimum sales target		$ 60,000,000						$ 19,000,000
Cumulative Relevant Sales	400,000,000						200,000,000
Sales Range Minimum	400,000,000						400,000,000
Royalty Payment Percentage Of Cumulative Sales Within Range	4.75%						4.50%
Sales Range Maximum	3,000,000,000						1,000,000,000
Royalty Payment Percentage Of Sales Over Range	5.50%						6.50%
Cumulative Sales Range 2nd Tier	$ 3,000,000,000						$ 1,000,000,000
Loss Contingency, Pending Claims, Number					4
Loss Contingency, New Claims Filed, Number			1	2		4