REVENUE RECOGNITION
Product Sales, Net
Product sales consist of FILSPARI and tiopronin products (Thiola and Thiola EC). The Company sells its products to specialty pharmacies and through direct-to-patient distributors worldwide, with the United States representing over 98% of the Company's net product sales.
The Company sells FILSPARI to two direct-to-patient specialty pharmacies in the United States. The Company sells its tiopronin products to patients and pharmacies, with distribution facilitated through a single direct-to-patient distributor. Revenues from product sales are recognized in satisfaction of a single performance obligation when the customer obtains control of the Company’s product. For FILSPARI, sales are recognized upon delivery of the product to the specialty pharmacies. The Company receives payments from its FILSPARI sales based on terms that are generally 30 days from shipment of the product to the specialty pharmacy. For the Company's tiopronin products, product sales are recognized upon delivery to the patient. The Company receives payments from sales of its tiopronin products, primarily through third party payers, based on terms that generally are within 30 days of delivery of product to the patient. Contracts do not contain significant financing components based on the typical period of time between performance of services and collection of consideration.
Deductions from Revenue
Revenues from product sales are recorded at the net sales price, which includes provisions resulting from discounts, rebates and co-pay assistance that are offered to customers, payers and other indirect customers relating to the Company’s sales of its products. These provisions are based on the estimates of the amounts earned or to be claimed on the related sales. These amounts are treated as variable consideration, estimated and recognized as a reduction of the transaction price at the time of the sale, using the most likely amount method, and are classified as a reduction of accounts receivable (if the amount is payable to a customer) or as a current liability (if the amount is payable to a party other than a customer). The Company includes these estimated amounts in the transaction price to the extent it is probable that a significant reversal of cumulative revenue recognized for such transactions will not occur. Where appropriate, these reserves take into consideration the Company’s historical experience, current contractual and statutory requirements and specific known market events and trends. Overall, these reserves reflect the Company’s best estimates of the amount of consideration to which it is entitled based on the terms of the contract. If actual results in the future vary from the Company’s provisions, the Company will adjust the estimate, which would affect net product revenue and earnings in the period such variances become known. For the years ended December 31, 2025, 2024 and 2023, adjustments to net product revenue related to performance obligations satisfied in previous periods were $1.1 million, $0.5 million, and $0.4 million, respectively.
Government Rebates: The Company calculates the rebates that it will be obligated to provide to government programs and deducts these estimated amounts from its gross product sales at the time the revenues are recognized. Allowances for government rebates and discounts are established based on an estimated allocation of payers and the government-mandated discounts applicable to government-funded programs. Rebate discounts are included in accrued expenses in the accompanying Consolidated Balance Sheets.
Commercial Rebates: The Company calculates the rebates it incurs according to any contracts with certain commercial payers and deducts these amounts from its gross product sales at the time the revenues are recognized. Allowances for commercial rebates are established based on actual payer information, which is reasonably estimated at the time of delivery for applicable products. Rebate discounts are included in accrued expenses in the accompanying Consolidated Balance Sheets.
Prompt Pay Discounts: The Company offers discounts to certain customers for prompt payments. The Company accrues for the calculated prompt pay discount based on the gross amount of each invoice for those customers at the time of sale.
Other Fees: The Company pays service fees to certain customers based on a contractually fixed percentage of the wholesale acquisition cost and fees for data. Other fees are recorded as an offset to revenue based on contractual terms at the time revenue from the sale is recognized.
Product Returns: Consistent with industry practice, the Company offers its customers a limited right to return product purchased directly from the Company, which is principally based upon the product’s expiration date. Historically, returns have been immaterial.
Co-pay Assistance: The Company offers a co-pay assistance program, which is intended to provide financial assistance to qualified commercially insured patients with prescription drug co-payments required by payers. The calculation of the accrual for co-pay assistance is based on an estimate of claims and the estimated cost per claim associated with product that has been recognized as revenue.
The following table summarizes net product sales for the year ended December 31, 2025, 2024 and 2023 (in thousands):
Year Ended December 31,
202520242023
FILSPARI$322,005 $132,222 $29,208 
Tiopronin products88,455 94,485 98,329 
Total net product sales$410,460 $226,707 $127,537 

Historical Timeline

Fiscal YearFiled
2025Feb 19, 2026Showing above
2024Feb 21, 2025
2023Feb 20, 2024
2022Feb 23, 2023
2021Feb 24, 2022
2020Mar 1, 2021
2019Feb 24, 2020
2018Feb 26, 2019

About Revenue Disclosures

Revenue disclosures under ASC 606 explain how a company identifies performance obligations, allocates transaction prices, and determines when revenue is recognized. This section is essential for understanding whether reported revenue reflects genuine economic activity or aggressive accounting choices. Analysts examine the mix of point-in-time versus over-time recognition, which directly affects revenue timing and comparability.

Key signals: rising contract liabilities (deferred revenue) suggest strong future revenue visibility, while declining contract assets may indicate slowing project milestones. Watch for variable consideration estimates — rebates, returns, and performance bonuses that require management judgment. Significant changes in disaggregated revenue by geography or product line can reveal shifting business mix before it appears in headline numbers. Compare revenue growth against contract liability growth to assess sustainability, and scrutinize any changes in the timing of recognition that coincide with earnings pressure.