6. ACCOUNTS RECEIVABLE AND RESERVES FOR PRODUCT SALES

The Company’s accounts receivable arise from product sales, government research contracts and other grants. They are generally stated at the invoiced amount and do not bear interest. Revenues from product sales are recorded at the net sales price (transaction price), which includes estimates of variable consideration for which reserves are established and which result from Medicaid rebates, governmental chargebacks including Public Health Services chargebacks, prompt pay discounts, co-pay assistance and distribution fees. These reserves are based on the amounts earned or to be claimed on the related sales and are classified as reductions of accounts receivable (if no payments are required of us), including Public Health Services chargebacks, prompt pay discounts and certain distribution fees, or a current liability (if a payment is required of us), including Medicaid rebates, co-pay assistance and certain distribution fees.

The accounts receivable from product sales represents receivables due from the Company’s specialty distributor and specialty pharmacies in the U.S. as well as certain distributors in the EU, Brazil, Israel and the Middle East. The Company monitors the financial performance and creditworthiness of its customers so that it can properly assess and respond to changes in the customers’ credit profiles. The Company provides reserves against trade receivables for estimated losses that may result from a customer’s inability to pay. Amounts determined to be uncollectible are written-off against the established reserve. As of September 30, 2018, the credit profiles for the Company’s customers are deemed to be in good standing and write-offs of accounts receivable are not considered necessary. Historically, no accounts receivable amounts related to government research contracts and other grants have been written off and, thus, an allowance for doubtful accounts receivable related to government research contracts and other grants is not considered necessary.

The following table summarizes the components of the Company’s accounts receivable for the periods indicated:

	As of September 30, 2018		As of December 31, 2017
	(in thousands)
Product sales, net of discounts and allowances	$	47,809	$	28,539
Government contract receivables		792		929
Total accounts receivable	$	48,601	$	29,468

The balance for government contract receivables for both periods presented is subject to government audit and will not be collected until the completion of the audit.

The following table summarizes an analysis of the change in reserves for discounts and allowances for the periods indicated:

	Chargebacks			Rebates			Prompt Pay			Other			Total
	(in thousands)
Balance, as of December 31, 2017	$	995		$	6,959		$	169		$	464		$	8,587
Provision		9,308			19,298			1,804			4,195			34,605
Payments/credits		(9,502	)		(6,479	)		(1,526	)		(2,532	)		(20,039	)
Balance, as of September 30, 2018	$	801		$	19,778		$	447		$	2,127		$	23,153

The following table summarizes the total reserves above included in the Company’s unaudited condensed consolidated balance sheets for the periods indicated:

	As of September 30, 2018		As of December 31, 2017
	(in thousands)
Reduction to accounts receivable	$	1,469	$	1,285
Component of accrued expenses		21,684		7,302
Total reserves	$	23,153	$	8,587