6. Stock-Based Awards

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2025 Equity Incentive Plan

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In April 2025, the Company’s board of directors adopted the 2025 Equity Incentive Plan (the “2025 Plan”), and in June 2025, the Company’s stockholders approved the 2025 Plan. Upon the 2025 Plan becoming effective, no further grants can be made under the Company’s 2015 Equity Incentive Plan (the “2015 Plan”). The 2025 Plan provides for the grant of incentive stock options, nonqualified stock options, stock appreciation rights, restricted stock awards, restricted stock unit (“RSU”) awards, cash-based awards, and other stock-based awards. The number of shares initially reserved for issuance under the 2025 Plan was 25,532,993 shares of common stock, which includes (i) 9,000,000 new shares of common stock, (ii) 3,957,232 shares of common stock that remained available for future grant under the 2015 Plan upon adoption of the 2025 Plan and (iii) up to 12,575,761 shares of common stock underlying outstanding awards under the 2015 Plan and the former 2012 Equity Compensation Plan, which may become available for issuance under the 2025 Plan if and as such awards expire, are otherwise terminated, settled in cash, or repurchased by the Company. The shares of common stock underlying any awards that expire, or are otherwise terminated, settled in cash or repurchased by the Company under the 2025 Plan will be added back to the shares of common stock available for issuance under the 2025 Plan. As of June 30, 2026, 6,754,427 shares remained available for grant under the 2025 Plan. The Company had 5,651,560 stock options and 1,874,582 RSUs outstanding as of June 30, 2026 under the 2025 Plan.

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2024 Inducement Plan

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In November 2024, the Company’s board of directors adopted the 2024 Inducement Plan (the “2024 Inducement Plan”). The 2024 Inducement Plan is a non-stockholder approved stock plan adopted pursuant to the “inducement exception” provided under Nasdaq listing rules. The only employees eligible to receive grants of awards under the 2024 Inducement Plan are individuals who satisfy the standards for inducement grants under Nasdaq rules, generally including individuals who were not previously an employee or director of the Company. Under the terms of the 2024 Inducement Plan, the Company may grant up to 2,000,000 shares of common stock pursuant to nonqualified stock options, stock appreciation rights, restricted stock awards, RSU awards, and other stock awards. The shares of common stock underlying any awards that expire, or are otherwise terminated, settled in cash or repurchased by the Company under the 2024 Inducement Plan will be added back to the shares of common stock available for issuance under the 2024 Inducement Plan. As of June 30, 2026, 502,830 shares remained available for grant under the 2024 Inducement Plan. The Company had 1,172,000 stock options and 250,875 RSUs outstanding as of June 30, 2026 under the 2024 Inducement Plan.

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2017 Inducement Plan

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In July 2017, the Company’s board of directors adopted the 2017 Inducement Plan (the “2017 Inducement Plan”). The 2017 Inducement Plan is a non-stockholder approved stock plan adopted pursuant to the “inducement exception” provided under Nasdaq listing rules. The Company had 323,500 stock options outstanding as of June 30, 2026 under the 2017 Inducement Plan. All shares of common stock that were eligible for issuance under the 2017 Inducement Plan after October 1, 2018, including any shares underlying any awards that expire or are otherwise terminated, reacquired to satisfy tax withholding obligations, settled in cash or repurchased by the Company in the future that would have been eligible for re-issuance under the 2017 Inducement Plan, were retired.  

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2015 Equity Incentive Plan

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In September 2015, the Company’s board of directors adopted the 2015 Plan, and the Company’s stockholders approved the 2015 Plan. The 2015 Plan became effective in connection with the Company’s initial public offering in October 2015. Upon the 2025 Plan becoming effective, no further grants can be made under the 2015 Plan. The Company had 8,245,932 stock options and 1,315,806 RSUs outstanding as of June 30, 2026 under the 2015 Plan.

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Stock Option Valuation

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The weighted average assumptions the Company used to estimate the fair value of stock options granted during the six months ended June 30, 2026 and 2025 were as follows:

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The Company recognizes compensation expense for awards over their vesting period. Compensation expense for awards includes the impact of forfeitures in the period when they occur.

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Stock Options

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The following table summarizes stock option activity for the six months ended June 30, 2026:

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The weighted average grant date fair value of stock options granted during the six months ended June 30, 2026 was $2.50 per share.

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Restricted Stock Units

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The following table summarizes RSU activity for the six months ended June 30, 2026:

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Stock-Based Compensation

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Stock-based compensation expense included in total costs and expenses on the condensed consolidated statement of operations and comprehensive loss included the following:

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As of June 30, 2026, the Company had unrecognized stock-based compensation expense for stock options and RSUs of $18.0 million and $9.3 million, respectively, which is expected to be recognized over weighted average periods of 3.0 years and 2.9 years, respectively.