The Company approved the 2013 Equity Incentive Plan in October 2013, which was amended in June 2016 and June 2018 (Amended 2013 Plan). The Amended 2013 Plan provided for the granting of stock options, restricted stock units (RSU), stock appreciation rights, and stock units to certain employees, members of the board of directors and consultants of the Company.

In May 2023, the Company's Board of Directors approved the 2023 Equity Incentive Plan (the 2023 Equity Plan) to replace the Amended 2013 Plan. On June 30, 2023, the Company's stockholders approved the 2023 Equity Plan at the Company's 2023 annual meeting of stockholders. Pursuant to the 2023 Equity Plan, the Company cannot make any further grants under the Amended 2013 Plan, though awards previously granted under the Amended 2013 Plan still remain outstanding. The 2023 Equity Plan is effective for a period of ten years after June 30, 2023, and a total of 5,450,000 shares of the Company’s common stock, in addition to shares of the Company’s common stock that are subject to awards granted under the Amended 2013 Plan that are outstanding as of such date and that are subsequently forfeited, cancelled, or expire before being exercised or settled in full, are authorized for issuance under the 2023 Equity Plan. As of June 30, 2026, there were 2,047,160 shares of common stock available for grant under the 2023 Equity Plan.

In 2022, the Company granted performance cash settled bonus awards (CSBUs) under the Management Cash Incentive Plan, as amended (the Management Cash Incentive Plan). As the performance criteria had been met in February 2023, the awards, which are equal in value to the closing price per share of the Company's common stock on Nasdaq on the payment date, will vest in four annual installments from the date of grant based on continued service, and entitle employees to receive cash payments for each vested CSBU, on the earlier of (i) four years from the date of grant or (ii) a change of control.

In 2026, the Company granted additional CSBUs that are not subject to performance criteria and vest solely based on continued service over four years, with payment terms consistent with the 2022 awards. As of June 30, 2026, $1.5 million was accrued as compensation expense for CSBUs. Subsequent to June 30, 2026, the Company settled the outstanding liability associated with the 2022 CSBUs through cash payments of approximately $1.2 million in accordance with the terms of the awards.

The Company recognizes stock-based compensation expense over the requisite service period. The Company's share-based awards are accounted for as equity instruments, except for cash awards and CSBUs, which are accounted for as liabilities. The amounts included in the consolidated statements of operations relating to stock-based compensation associated with the two equity incentive plans, cash awards, and CSBUs are as follows:

Stock Options

As of June 30, 2026, unamortized stock-based compensation for stock options outstanding was $7.9 million and is expected to be recognized over a weighted average period of 2.50 years. Total unrecognized compensation cost will be adjusted for future forfeitures, if necessary.

Restricted Stock Units

There were no RSUs granted during the six months ended June 30, 2026. The total grant date fair value of RSUs vested was $0.8 million for the six months ended June 30, 2026. As of June 30, 2026, the outstanding RSUs had unamortized stock-based compensation of $0.2 million with a weighted-average remaining recognition period of 0.49 years and an aggregate intrinsic value of $0.2 million.

Employee Stock Purchase Plan

At June 30, 2026, the Company had 4,112,174 shares available for issuance under the 2016 Employee Stock Purchase Plan (2016 ESPP). A summary of the weighted-average grant-date fair value, and total stock-based compensation expense recognized related to the 2016 ESPP are as follows: