Collaboration Agreements (EYLEA) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2014
Collaboration Agreement [Line Items]
Number of sales milestone payments the Company received	1	2
Levels of twelve month sales at which sales milestone payments were received - 700 million	$ 700,000,000
Period for Achieving Sales Target for Milestone Payment, Rolling Basis			12 months
levels of twelve months sales at which sales milestone payments maybe received - 1 billion			1,000,000,000
levels of twelve month sales at which sales milestone payments maybe received - 200 million			200,000,000
Deferred Revenue, Additions			25,500,000
Levels of twelve month sales at which sales milestone payments were received - 500 million		500,000,000
Levels of twelve month sales at which sales milestone payments were received - 600 million		600,000,000
sales achievement - $600 million
Collaboration Agreement [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized		15,000,000
sales achievement - $500 million
Collaboration Agreement [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized		15,000,000
sales achievement - $700 million
Collaboration Agreement [Line Items]
Revenue Recognition, Milestone Method, Revenue Recognized	15,000,000
sales achievement - $1 billion
Collaboration Agreement [Line Items]
Maximum amount of sales milestone payments if total sales achieve specific levels			45,000,000
sales achievement - $200 million
Collaboration Agreement [Line Items]
Maximum amount of sales milestone payments if total sales achieve specific levels			30,000,000
BRVO
Collaboration Agreement [Line Items]
Reimbursement of Regeneron research and development expenses		$ 15,700,000