Net Product Sales (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Revenue Disclosure [Line Items]
Branded Prescription Drug Fee	$ 40,600,000
Net product sales	1,750,762,000	1,425,839,000	858,093,000
Activity of Sales Related Deductions [Roll Forward]
Balance	24,781,000	24,601,000	18,826,000	2,218,000
Provision related to current period sales	111,855,000	89,875,000	62,251,000
Credits/payments	(111,675,000)	(84,100,000)	(45,643,000)
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance	3,083,000	4,400,000	2,983,000	585,000
Provision related to current period sales	33,117,000	25,936,000	14,153,000
Credits/payments	(34,434,000)	(24,519,000)	(11,755,000)
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance	21,166,000	19,663,000	15,298,000	1,451,000
Provision related to current period sales	77,160,000	62,984,000	45,028,000
Credits/payments	(75,657,000)	(58,619,000)	(31,181,000)
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance	532,000	538,000	545,000	182,000
Provision related to current period sales	1,578,000	955,000	3,070,000
Credits/payments	(1,584,000)	(962,000)	(2,707,000)
Customer concentration risk | Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	73.00%	76.00%	78.00%
EYLEA
Revenue Disclosure [Line Items]
Net product sales	1,736,400,000	1,408,700,000	837,900,000
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	$ 14,400,000	$ 17,100,000	$ 20,200,000