10. Stock-Based Compensation Stock

2015 Equity Plan

The 2015 Equity Plan provides for increases to the number of shares reserved for issuance thereunder each January 1 equal to 4.0% of the total shares of the Company’s common stock outstanding as of the immediately preceding December 31, unless a lesser amount is stipulated by the Compensation Committee of the Company’s Board. As of March 31, 2025, there were 67,316 shares available for future issuance under the 2015 Equity Plan. On January 1, 2025, the number of shares available for future issuance under the 2015 Equity Plan increased by 348,109.

2018 Employee, Director and Consultant Equity Incentive Plan

On March 28, 2018, EIP adopted the 2018 Plan, which was assumed by the Company pursuant to and in accordance with the terms of the Merger Agreement. Under the 2018 Plan, the Company may issue incentive stock options, non-qualified stock options, stock grants, and other stock-based awards to employees, directors, and consultants, as specified in the 2018 Plan and subject to applicable SEC and Nasdaq rules and regulations. The Board has the authority to determine to whom options or stock will be granted, the number of shares, the term, and the exercise price. Options granted under the 2018 Plan have a term of up to ten years and generally vest over a four-year period with 25% of the options vesting after one-year of service and the remainder vesting monthly thereafter. As of March 31, 2025, there were no shares available for issuance.

2024 Inducement Grants

During the year ended December 31, 2024, the Company granted stock options outside of the 2015 Equity Plan and the 2018 Plan to purchase an aggregate of 71,712 shares of common stock as material inducements to the employment of five new employees, in each case, in accordance with Nasdaq Listing Rule 5635(c)(4). Each such inducement option has a term of ten years and vests over a 36-month period commencing on the last day of the month in which the grant date occurred (subject to the employee's continued employment with the Company).

The Company recorded stock-based compensation expense in the following expense categories of its consolidated statements of operations and comprehensive loss:

The following table summarizes the activity related to all stock option grants for the three months ended March 31, 2025:

The Black-Scholes option pricing model was used to estimate the grant date fair value of each stock option grant at the time of grant using the following weighted-average assumptions: 

At March 31, 2025, there was $2.0 million of unrecognized compensation expense that will be recognized over a weighted-average period of 2.2 years.

During the three months ended March 31, 2024, the Company granted 39,721 options in lieu of 2023 executive bonus compensation.