2019 Stock Option and Grant Plan

The Company’s 2019 Plan, as amended, provides for the Company to sell or issue common stock or restricted common stock or to grant incentive stock options or nonqualified stock options for the purchase of common stock, to employees, members of the Board, and consultants of the Company. The 2019 Plan is administered by the Board or at the discretion of the Board by a committee of the Board. The exercise prices, vesting periods, and other restrictions are determined at the discretion of the Board or a committee of the Board, except that the exercise price per share of stock options may not be less than 100% of the fair market value of the share of common stock on the date of grant and the contractual term of stock option may not be greater than 10 years. Stock options granted to date typically vest and become exercisable over four years from the date of grant.

As of the date the 2024 Plan became effective, there will be no further awards granted under the 2019 Plan, but all outstanding awards under the 2019 Plan will continue to be governed by their existing terms. 1,820,649 stock options to purchase common stock were outstanding under the 2019 Plan as of June 30, 2026.

2024 Stock Option and Incentive Plan

In August 2024, the Company's board of directors adopted, and its stockholders approved, the 2024 Plan, which became effective in September 2024. The 2024 Plan allows the Company to make equity-based and cash-based incentive awards to its officers, employees, directors and consultants. The 2024 Plan provides for the grant of incentive stock options, stock options, stock appreciation rights, restricted shares of common stock, RSUs, dividend equivalent rights and cash bonuses. The number of shares initially reserved for issuance under the 2024 Plan was 3,065,000 shares. In addition, the number of shares reserved and available for issuance under the 2024 Plan will automatically increase on January 1, 2025 and each January 1 thereafter, by five percent (5%) of the sum of the outstanding number of shares of common stock and the numbers of shares of common stock issuable pursuant to the exercise of any outstanding warrants to acquire common stock for a nominal exercise price on the immediately preceding December 31 or such lesser number of shares as determined by the compensation committee. The number of shares reserved under the 2024 Plan is subject to adjustment in the event of a stock split, stock dividend or other change in our capitalization. As of June 30, 2026, 2,740,557 stock options to purchase common stock and 162,493 RSUs were outstanding under the 2024 Plan, and 4,140,451 shares remained available for future grant under the 2024 Plan. The shares available for issuance under the 2024 Plan may be authorized but unissued shares or shares reacquired by the Company.

The shares of common stock underlying any awards under the 2024 Plan and the 2019 Plan that are forfeited, cancelled, held back upon exercise or settlement of an award to satisfy the exercise price or tax withholding, reacquired by the Company prior to vesting, satisfied without the issuance of stock, expire or are otherwise terminated (other than by exercise) will be added back to the shares of common stock available for issuance under the 2024 Plan.

2024 Employee Stock Purchase Plan

In August 2024, the Company's board of directors adopted, and its stockholders approved, the 2024 ESPP, which became effective in September 2024. A total of 289,436 shares of common stock were initially reserved for issuance under the 2024 ESPP. The 2024 ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1, 2025 and each January 1 thereafter, by the least of (i) 578,872 shares of common stock, (ii) one percent (1%) of the number of shares of common stock issued and outstanding on the immediately preceding December 31, or (iii) such lesser number of shares of common stock as determined by the administrator of the 2024 ESPP. The number of shares reserved under the 2024 ESPP is subject to adjustment in the event of a stock split, stock dividend or other change in our capitalization. During the six months ended June 30, 2026, the Company recognized $0.2 million of expense related to the 2024 ESPP. As of June 30, 2026, 1,062,708 shares remained available for issuance under the 2024 ESPP. 10,222 shares were issued under the 2024 ESPP during the three and six months ended June 30, 2026. No shares were issued under the 2024 ESPP during the three and six months ended June 30, 2025.

2026 Inducement Plan

In March 2026, the Company's board of directors adopted and approved the 2026 Plan. The 2026 Plan allows the Company to make equity-based and cash-based incentive awards to its officers, employees, directors and consultants. The 2026 Plan provides for the grant of nonqualified stock options, stock options, stock appreciation rights, restricted shares of common stock, RSUs, dividend equivalent rights and cash bonuses. The number of shares initially reserved for issuance under the 2026 Plan is 130,000 shares. Also, in March 2026, the Company's board of directors approved an increase to the shares reserved under the 2026 Plan to 900,000. The number of shares reserved under the 2026 Plan is subject to adjustment in the event of a stock split, stock dividend or other change in our capitalization. As of June 30, 2026, 610,000 shares remained available for issuance under the 2026 Plan. 290,000 stock options to purchase common stock were outstanding under the 2026 Plan as of June 30, 2026.

Stock option valuation

Summary of option activity

As of June 30, 2026, total unrecognized compensation cost related to the unvested stock option awards to employees, directors, and nonemployees is $47.0 million, which is expected to be recognized over a weighted-average period of 3.0 years.

Summary of restricted stock unit activity

The fair values of RSUs are based on the fair market value of the Company's common stock on the date of grant. Each RSU represents a contingent right to receive one share of the Company's common stock upon vesting. In general, RSUs vest in equal quarterly installments over four years from the grant date. The following table summarizes the Company's RSU activity for the six months ended June 30, 2026 (in thousands except share and per share amounts):

As of June 30, 2026, total unrecognized stock compensation expense related to the unvested RSUs to employees is $6.5 million, which is expected to be recognized over a weighted average period of 3.6 years.

Stock-based compensation