Note 13. Debt

​

Debt consists of the following:

​

​

Credit Agreement

​

2029 Convertible Notes

​

In September 2023, the Company issued the 2029 Convertible Notes, in the aggregate principal amount of $345.0

million in a private offering pursuant to Section 4(a)(2) and Rule 144A under the Securities Act of 1933, as amended. The Company used portions of the net proceeds from the 2029 Convertible Notes to (i) repay approximately $200.0 million of the Company’s borrowings under the Wells Fargo Term Loan and (ii) repurchase $50.0 million of the Company’s common stock.

​

In connection with the issuance of the 2029 Convertible Notes, the Company incurred approximately $10.8 million of debt issuance costs, which primarily consisted of underwriting, legal and other professional fees. Unamortized debt issuance costs related to the 2029 Convertible Notes were $5.8 million and $6.3 million as of March 31, 2026 and December 31, 2025, respectively. The fair value of the 2029 Convertible Notes was approximately $312.4 million as of March 31, 2026 based on Level 2 inputs.

​

The total interest expense related to the 2029 Convertible Notes was $2.2 million, with coupon interest expense of $1.7 million, and the amortization of debt issuance cost of $0.5 million in both periods presented.

​

The 2029 Convertible Notes are general senior, unsecured obligations and bear an interest rate of 2.0% per year. The 2029 Convertible Notes were issued pursuant to an indenture, dated September 15, 2023, or the Indenture, between the Company and U.S. Bank Trust Company, National Association, as trustee.

​

The 2029 Convertible Notes will rank senior in right of payment to all of the Company’s indebtedness that is expressly subordinated in right of payment to the 2029 Convertible Notes; equal in right of payment to all of the Company’s unsecured indebtedness that is not so subordinated; effectively junior to any of the Company’s secured indebtedness to the extent of the value of the assets securing such indebtedness, including any amount outstanding under the Company’s credit facilities; and structurally junior to all indebtedness and other liabilities of the Company’s current or future subsidiaries, including trade payables.

​

Interest is payable semi-annually in arrears on March 15 and September 15 of each year. The 2029 Convertible Notes may bear additional interest under specified circumstances relating to the Company’s failure to comply with its reporting obligations under the Indenture or if the 2029 Convertible Notes are not freely tradeable as required by the Indenture.

​

The 2029 Convertible Notes will mature on March 15, 2029, unless earlier converted, repurchased or redeemed.

​

Conversions of the 2029 Convertible Notes will be settled in cash up to the aggregate principal amount of the 2029 Convertible Notes to be converted, and cash, shares of common stock or a combination of cash and shares of common stock, at the Company’s election, with respect to the remainder, if any, of the Company’s conversion obligation in excess of the aggregate principal amount.

​

Holders may convert their 2029 Convertible Notes at their option prior to the close of business on the business day immediately preceding December 15, 2028, in multiples of $1,000 principal amount, only under the following circumstances: (i) during any calendar quarter commencing after the calendar quarter ending on December 31, 2023 (and only during such calendar quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a period of 30 consecutive trading days ending on and including, the last trading day of the immediately preceding calendar quarter is greater than or equal to 130% of the conversion price for the 2029 Convertible Notes on each applicable trading day, (ii) during the five business day period after any five consecutive trading day period in which the trading price, as defined in the Indenture, per $1,000 principal amount of the 2029 Convertible Notes for each trading day of the measurement period was less than 98% of the product of the last reported sale price of the Company’s common stock and the conversion rate on each such trading day, (iii) if the Company calls the 2029 Convertible Notes for redemption, at any time prior to the close of business on the second scheduled trading day immediately preceding the redemption date, and (iv) upon the occurrence of specified corporate events defined in the Indenture.

​

On or after December 15, 2028, until the close of business on the second scheduled trading day immediately preceding

the maturity date, holders may convert all or any portion of their 2029 Convertible Notes, in multiples of $1,000 principal amount, at the option of the holder regardless of the foregoing circumstances.

​

The Company may redeem the 2029 Convertible Notes, at its option, in whole or in part (subject to certain limitations), on or after September 20, 2026 and prior to the 41^st scheduled trading day preceding the maturity date, if the last reported sale price of the Company’s common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading day period (including the last trading day of such period) ending on and including the trading day immediately preceding the date on which the Company provides notice of redemption at a redemption price equal to 100% of the principal amount of the 2029 Convertible Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date.

​

The initial conversion rate is 15.8821 shares of the Company’s common stock per $1,000 principal amount of the 2029 Convertible Notes, which represents an initial conversion price of approximately $62.96 per share of common stock. The initial conversion price of $62.96 represents a premium of approximately 35.0% over the last reported sale price of the Company’s common stock on Nasdaq Global Select Market on September 12, 2023. The conversion rate is subject to adjustment under certain circumstances in accordance with the terms of the Indenture.

​

If a fundamental change, as defined in the Indenture, occurs at any time prior to the maturity date, then, subject to certain conditions, holders of the 2029 Convertible Notes may require the Company to repurchase for cash all or any portion of their 2029 Convertible Notes at a repurchase price equal to 100% of the principal amount of the 2029 Convertible Notes to be repurchased, plus any accrued and unpaid interest. In addition, following certain specified corporate events or if the Company issues a notice of redemption, the Company will, under certain circumstances, increase the conversion rate for holders who convert their 2029 Convertible Notes in connection with such corporate event or during a redemption period.

​

Syndicated Line of Credit Facility with ICBC Bank – Due November 2033

​

In January 2024, the Company entered into a credit agreement with Industrial and Commercial Bank of China Limited, or ICBC Bank, acting as a lender and as agent for other lenders. The credit agreement allows the Company to borrow up to $40.0 million secured by equipment and buildings at our Chinese subsidiary. The interest rate and other terms will be determined at the time of the borrowing, depending on the type of loan requested. The credit agreement expires in November 2033.

​

The loan bears interest at the prime rate as published by The People’s Bank of China minus 0.2%. Interest payments are due quarterly and repayment of the principal amount is biannual and begins in May 2026. As of March 31, 2026, the Company had $25.1 million of principal outstanding under this loan, which is recorded net of loan issuance costs of $1.3 million.

​

Interest Rate Swap Contract

​

As of March 31, 2026, the fair value of the loans listed above approximated their carrying amount based on Level 2 inputs, with the exception of the 2029 Convertible Notes. For the Wells Fargo Term Loan, the Company has entered into a fixed interest rate swap contract to exchange the variable interest rates for fixed interest rates. The interest rate swap contract is recorded at fair value in the other long-term liabilities line in the condensed consolidated balance sheets. Changes in the fair values of interest rate swaps were a $2.0 million gain and a $2.9 million loss for the three months ended March 31, 2026 and 2025, respectively.

​

Covenants

​

At March 31, 2026 and December 31, 2025, the Company was in compliance with all of its debt covenants.