Net Product Sales (Tables)

9 Months Ended

Sep. 30, 2017

Revenue from External Customer [Line Items]

Revenue from External Customers by Products and Services [Table Text Block]

	Three Months Ended September 30,				Nine Months Ended September 30,
Net Product Sales in the United States	2017		2016		2017		2016
EYLEA®	$	953,279	$	853,588	$	2,727,132	$	2,465,369
ARCALYST®	4,088		3,880		12,613		10,500
Net Product Sales	$	957,367	$	857,468	$	2,739,745	$	2,475,869

Schedules of Concentration of Risk, by Risk Factor [Table Text Block]

The Company had product sales to certain customers that accounted for more than 10% of total gross product revenue for each of the three and nine months ended September 30, 2017 and 2016. Sales to each of these customers as a percentage of the Company's total gross product revenue are as follows:

	Three Months Ended September 30,				Nine Months Ended September 30,
	2017		2016		2017		2016
Besse Medical, a subsidiary of AmerisourceBergen Corporation	51	%	54	%	51	%	56	%
McKesson Corporation	29	%	28	%	29	%	28	%
Curascript SD Specialty Distribution, a subsidiary of Express Scripts	19	%	17	%	19	%	15	%

Sales Related Deductions Activity

The following table summarizes the provisions and credits/payments for these sales-related deductions during the nine months ended September 30, 2017 and 2016.

	Rebates & Chargebacks			Distribution- Related Fees			Other Sales- Related Deductions			Total
Balance as of December 31, 2016	$	12,712		$	29,465		$	3,674		$	45,851
Provisions	121,599			140,860			33,518			295,977
Credits/payments	(108,811		)	(136,272		)	(21,444		)	(266,527		)
Balance as of September 30, 2017	$	25,500		$	34,053		$	15,748		$	75,301
Balance as of December 31, 2015	$	6,419		$	48,313		$	517		$	55,249
Provisions	63,510			113,755			22,812			200,077
Credits/payments	(62,503		)	(135,483		)	(19,587		)	(217,573		)
Balance as of September 30, 2016	$	7,426		$	26,585		$	3,742		$	37,753