For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

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Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

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Total of the deductions in a given period to allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs, representing receivables written off as uncollectible and portions of the reserves utilized, respectively.

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Net Product Sales (Details) - USD ($) $ in Thousands	3 Months Ended
Net Product Sales (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014
Revenue Disclosure [Line Items]
Net product sales	$ 784,182	$ 544,573
Activity of Sales Related Deductions [Roll Forward]
Balance	42,465	38,072	$ 55,249	$ 24,781
Provision related to current period sales	57,583	37,517
Credits/payments	(70,367)	(24,226)
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance	7,847	4,657	6,419	3,083
Provision related to current period sales	18,885	11,353
Credits/payments	(17,457)	(9,779)
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance	33,748	32,911	48,313	21,166
Provision related to current period sales	35,788	24,781
Credits/payments	(50,353)	(13,036)
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance	870	504	$ 517	$ 532
Provision related to current period sales	2,910	1,383
Credits/payments	$ (2,557)	$ (1,411)
Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	60.00%	69.00%
EYLEA
Revenue Disclosure [Line Items]
Net product sales	$ 780,900	$ 541,100
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	$ 3,300	$ 3,500