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		12 Months Ended
Net Product Sales (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2016
Revenue Disclosure [Line Items]
Net product sales	$ 858,245	$ 784,182
Activity of Sales Related Deductions [Roll Forward]
Balance	56,033	42,465	$ 55,249	$ 45,851
Provision related to current period sales	89,603	57,583
Credits/payments	(79,421)	(70,367)
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance	23,118	7,847	6,419	12,712
Provision related to current period sales	38,908	18,885
Credits/payments	(28,502)	(17,457)
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance	28,353	33,748	48,313	29,465
Provision related to current period sales	41,175	35,788
Credits/payments	(42,287)	(50,353)
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance	4,562	870	$ 517	$ 3,674
Provision related to current period sales	9,520	2,910
Credits/payments	$ (8,632)	$ (2,557)
Besse Medical [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	53.00%	60.00%
EYLEA
Revenue Disclosure [Line Items]
Net product sales	$ 854,400	$ 780,900
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	$ 3,800	$ 3,300
McKesson Corporation [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	27.00%	28.00%
Curascript SD [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	19.00%	11.00%
Maximum [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage		10.00%
Maximum [Member] \| Curascript SD [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage			10.00%