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Percentage of revenue generated from a single external customer that accounts for 10 percent or more of an entity's revenues.

+ References

No definition available.

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1(a))

-URI http://asc.fasb.org/extlink&oid=6880815&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 09

-Article 12

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6881521&loc=d3e24092-122690

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- Definition

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- Definition

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, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Revenue Disclosure [Line Items]
Net product sales	$ 333,893	$ 199,519	$ 652,633	$ 327,450
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2012			18,826
Provision related to current period sales			41,041
Credits/payments			(36,830)
Balance as of June 30, 2013	23,037		23,037
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2012			2,983
Provision related to current period sales			11,121
Credits/payments			(10,081)
Balance as of June 30, 2013	4,023		4,023
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2012			15,298
Provision related to current period sales			29,422
Credits/payments			(26,238)
Balance as of June 30, 2013	18,482		18,482
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance as of December 31, 2012			545
Provision related to current period sales			498
Credits/payments			(511)
Balance as of June 30, 2013	532		532
EYLEA
Revenue Disclosure [Line Items]
Net product sales	329,800	194,000	643,700	317,500
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	$ 4,100	$ 5,500	$ 8,900	$ 9,900
GrossSalesRevenue \| Customer concentration risk
Risks and Uncertainties [Abstract]
Concentration risk, percentage	76.00%	79.00%	77.00%	79.00%