Debt

12 Months Ended

Dec. 31, 2025

Debt

Debt

12.    Debt

Credit Line Agreement

In September 2015, the Company entered into a credit line with UBS (the “Credit Line”) providing for a $50.0 million revolving line of credit which was fully drawn down in 2016. The Credit Line was amended in July 2017 and bears interest at 30-day LIBOR plus 1.10%. The interest rate was subsequently changed to the 30-day SOFR average, plus

1.21%. The SOFR rate is variable. The interest rate as of December 31, 2025 was 4.29%. The Credit Line was subsequently increased from $50.0 million to $150.0 million in 2020. In June 2023, the Credit Line decreased from $150.0 million to $100.0 million. In November 2022, the Company drew down $30.0 million from the $100.0 million available from the Credit Line. The Credit Line is secured by a first priority lien and security interest in the Company’s money market and marketable securities held in its managed investment account with UBS. The Company is required to maintain a minimum of at least $150.0 million in its UBS accounts as collateral which is classified as cash, cash equivalents, and short-term investments in the consolidated balance sheets. UBS has the right to demand full or partial payment of the Credit Line obligations and terminate the Credit Line, in its discretion and without cause, at any time. In October 2023, the interest rate for the Credit Line was subsequently changed to the 30-day SOFR average, plus 0.5%. As of December 31, 2025, the Company has drawn down a total of $80.0 million and there is $20.0 million remaining and available on the Credit Line.

For the years ended December 31, 2025, 2024, and 2023, the Company recorded interest expense of $4.1 million, $4.7 million, and $4.9 million, respectively. Interest payments totaling $4.1 million, $4.7 million, and $4.9 million had been made on the Credit Line during the years ended December 31, 2025, 2024, and 2023, respectively. As of December 31, 2025 and December 31, 2024, and the total principal amount outstanding including accrued interest was $80.3 million and $80.4 million, respectively.

Convertible Notes

In April 2020, the Company issued $287.5 million aggregate principal amount of Convertible Notes due 2027 in a private placement offering to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended. The Convertible Notes were senior, unsecured obligations of the Company and bore interest at a rate of 2.25% per year, payable in cash semi-annually. Upon conversion, the Convertible Notes were convertible into cash, shares of the Company’s common stock or a combination of cash and shares of the Company’s common stock, at the Company’s election.

The Company received net proceeds from the Convertible Notes of $278.3 million, after deducting the initial purchasers’ discounts and debt issuance costs. In 2020, the Company used approximately $79.2 million of the net proceeds from the Convertible Notes offering to repay its obligations under its credit agreement with OrbiMed Royalty Opportunities II, LP.

On July 19, 2024, the Company elected to exercise its optional redemption right to redeem all $287.5 million aggregate principal amount of its outstanding 2.25% Convertible Notes due 2027 and instructed Wilmington Trust, National Association, as trustee under the Convertible Notes Indenture (the “Indenture Agreement”) governing the Convertible Notes, to issue a redemption notice to registered holders of the Convertible Notes. The date fixed for the redemption of the Convertible Notes was October 11, 2024 (the “Redemption Date”). The redemption price for the Convertible Notes was equal to 100% of the principal amount of the Convertible Notes to be redeemed plus accrued and unpaid interest to, but excluding, the Redemption Date. The Company elected physical settlement with the Company’s shares of common stock as the settlement method to apply to all conversions of the Convertible Notes. All terms and conditions associated with physical settlement are noted within the terms of the original Indenture Agreement. The conversion rate for holders who converted their Convertible Notes in connection with the Company’s election to redeem the Convertible Notes was increased by 0.4284 additional shares pursuant to the Indenture Agreement.

Upon adoption of ASU 2020-06, Debt with Conversion and Other Options (Subtopic 470-20) and Derivative and Heading-Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in Entity’s Own Equity, the Company allocated all of the debt discount to long-term debt. The debt discount is amortized to interest expense using the effective interest method, computed to be 2.72%, over the life of the Convertible Notes or approximately its seven-year term.

The following table presents total interest expense recognized related to the Convertible Notes during the years as follows:

	December 31,
	2025			2024		2023
	(in thousands)
Cash interest expense
Contractual interest expense	$	—	$	2,157	$	6,469
Non-cash interest expense
Contractual interest expense		—		2,875		—
Amortization of debt discount and debt issuance cost		—		991		1,292
Total interest expense	$	—	$	6,023	$	7,761