Product Sales (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Revenue Disclosure [Line Items]
Net product sales	$ 3,718,463	$ 3,338,390	$ 2,689,478
Activity of Sales Related Deductions [Roll Forward]
Balance	85,302	45,851	55,249	$ 24,781
Provision related to current period sales	408,270	278,304	193,190
Credits/payments	(368,819)	(287,702)	(162,722)
Rebates and Chargebacks
Activity of Sales Related Deductions [Roll Forward]
Balance	29,840	12,712	6,419	3,083
Provision related to current period sales	167,755	93,385	61,124
Credits/payments	(150,627)	(87,092)	(57,788)
Distribution Related Fees
Activity of Sales Related Deductions [Roll Forward]
Balance	34,142	29,465	48,313	21,166
Provision related to current period sales	194,132	154,477	122,466
Credits/payments	(189,455)	(173,325)	(95,319)
Other Sales Related Deductions
Activity of Sales Related Deductions [Roll Forward]
Balance	21,320	3,674	517	$ 532
Provision related to current period sales	46,383	30,442	9,600
Credits/payments	(28,737)	(27,285)	(9,615)
EYLEA
Revenue Disclosure [Line Items]
Net product sales	3,701,917	3,323,081	2,676,040
ARCALYST
Revenue Disclosure [Line Items]
Net product sales	$ 16,546	$ 15,309	$ 13,438
Besse Medical \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	51.00%	55.00%	67.00%
McKesson Corporation \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	29.00%	28.00%	26.00%
Curascript SD \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	19.00%	16.00%
Curascript SD \| Minimum [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage	10.00%	10.00%	10.00%
Curascript SD \| Maximum [Member] \| Customer concentration risk \| Gross Sales Revenue
Risks and Uncertainties [Abstract]
Concentration risk, percentage			10.00%

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.

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