Product Sales (Tables)

12 Months Ended

Dec. 31, 2017

Net product sales consist of the following:



	Year Ended December 31,
Net Product Sales in the United States	2017		2016		2015
EYLEA	$	3,701,917	$	3,323,081	$	2,676,040
ARCALYST	16,546		15,309		13,438
Net Product Sales	$	3,718,463	$	3,338,390	$	2,689,478

Schedules of Concentration of Risk, by Risk Factor

The Company had product sales to certain customers that accounted for more than 10% of total gross product revenue for each of the years ended December 31, 2017, 2016, and 2015. Sales to each of these customers as a percentage of the Company's total gross product revenue are as follows:



	Year Ended December 31,
	2017		2016		2015
Besse Medical, a subsidiary of AmerisourceBergen Corporation	51	%	55	%	67	%
McKesson Corporation	29	%	28	%	26	%
Curascript SD Specialty Distribution, a subsidiary of Express Scripts	19	%	16	%	**

** For the year ended December 31, 2015, sales to Curascript SD Specialty Distribution represented less than 10% of total gross product revenue.

Sales Related Deductions Activity

The following table summarizes the provisions, and credits/payments, for these sales-related deductions for the years ended December 31, 2017, 2016, and 2015.



	Rebates & Chargebacks			Distribution- Related Fees			Other Sales- Related Deductions			Total
Balance as of December 31, 2014	$	3,083		$	21,166		$	532		$	24,781
Provisions	61,124			122,466			9,600			193,190
Credits/payments	(57,788		)	(95,319		)	(9,615		)	(162,722		)
Balance as of December 31, 2015	6,419			48,313			517			55,249
Provisions	93,385			154,477			30,442			278,304
Credits/payments	(87,092		)	(173,325		)	(27,285		)	(287,702		)
Balance as of December 31, 2016	12,712			29,465			3,674			45,851
Provisions	167,755			194,132			46,383			408,270
Credits/payments	(150,627		)	(189,455		)	(28,737		)	(368,819		)
Balance as of December 31, 2017	$	29,840		$	34,142		$	21,320		$	85,302