Net Product Sales (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenue Disclosure [Line Items]
Net product sales	$ 858,093,000	$ 44,686,000	$ 25,254,000
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2011	2,218,000
Provision related to current period sales	62,251,000
Credits/payments	(45,643,000)
Balance as of December 31, 2012	18,826,000	2,218,000
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2011	585,000
Provision related to current period sales	14,153,000
Credits/payments	(11,755,000)
Balance as of December 31, 2012	2,983,000
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2011	1,451,000
Provision related to current period sales	45,028,000
Credits/payments	(31,181,000)
Balance as of December 31, 2012	15,298,000
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2011	182,000
Provision related to current period sales	3,070,000
Credits/payments	(2,707,000)
Balance as of December 31, 2012	545,000
Customer concentration risk | Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	78.00%	42.00%
EYLEA
Revenue Disclosure [Line Items]
Net product sales	837,900,000	24,800,000
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	20,200,000	19,900,000	25,300,000
Net product sales, excluding deferred sales recognized as revenue			20,500,000
Deferred net product sales recognized as revenue			$ 4,800,000
Change in accounting estimate, deferred revenue - lower net loss per share			$ 0.06