13. Stock-Based Payments

2016 Employee Stock Purchase Plan

The 2016 Employee Stock Purchase Plan (the “2016 ESPP”) was adopted by the board of directors on December 15, 2015, approved by the stockholders on June 17, 2016, and became effective on July 6, 2016 upon the closing of the IPO. The number of shares of the Company’s common stock reserved for issuance under the 2016 ESPP automatically increases on the first day of each calendar year through the 2025 calendar year, in an amount equal to the least of (i) 117,333 shares of the Company’s common stock, (ii) 1.0% of the total number of shares of the Company’s common stock outstanding on the first day of the applicable year, and (iii) an amount determined by the Company’s board of directors. For the calendar year beginning January 1, 2023, the number of shares reserved for issuance under the 2016 ESPP was increased by 117,333 shares. At December 31, 2023, 258,504 shares remained available for future issuance under the 2016 ESPP.

2022 Inducement Stock Incentive Plan

On January 25, 2022, the Company’s board of directors adopted the 2022 Inducement Stock Incentive Plan (the “2022 Plan”), pursuant to which the Company may grant non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards. Awards under the 2022 Plan may only be granted to persons who (i) were not previously an employee or director of the Company or (ii) are commencing employment with the Company following a bona fide period of non-employment, in either case as an inducement material to the individual’s entering into employment with the Company and in accordance with the requirements of Nasdaq Stock Market Rule 5635(c)(4). In January 2023, the Company’s board of directors amended the 2022 Plan to increase the aggregate number of shares that can be granted by 750,000 shares. At December 31, 2023, 710,392 shares remained available for future issuance under the 2022 Plan.

2022 Equity Incentive Plan

The 2022 Stock Incentive Plan (the “2022 EIP”) was adopted by the board of directors on July 14, 2022, approved by the stockholders and became effective on September 15, 2022. The 2022 EIP replaced the 2016 Plan. Any options or awards outstanding under the 2016 Plan remained outstanding and effective. Under the 2022 EIP, the Company may grant incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units and other stock-based awards. At December 31, 2023, 1,170,425 shares remained available for future issuance under the 2022 EIP. Under the 2022 EIP, stock options may not be granted at less than fair value on the date of grant.

Stock Options

Terms of stock option agreements, including vesting requirements, are determined by the board of directors, subject to the provisions of the applicable plan. Stock option awards granted by the Company generally vest over four years, with 25% vesting on the first anniversary of the vesting commencement date and 75% vesting ratably, on a monthly basis, over the remaining three years. Such awards have a contractual term of ten years from the grant date.

The Company has granted options to purchase 7,500 shares of common stock to an advisor that vest solely upon the achievement of performance-based criteria. As of December 31, 2022, none of these performance-based criteria had been achieved. As of December 31, 2023, there was $0.3 million of unrecognized compensation cost related to this option, with a remaining contractual period of 2.7 years.

Pursuant to the terms of the Merger Agreement, the Company assumed certain Tyme stock options that were outstanding and unexercised immediately prior to the completion of the Merger. The Company issued options to purchase 692,460 shares of the Company’s common stock at the completion of the Merger on September 16, 2022. The original terms and restrictions on such Tyme options shall continue in full force and effect except for certain options held by certain Tyme employees which were modified to extend the exercise period to up to two years. The Company recorded $0.4 million of one-time additional stock-based compensation expense related to the modification.

There were no stock options exercised during the year ended December 31, 2023. The intrinsic value of stock options exercised during the year ended December 31, 2022 was $0.1 million. Cash received from option exercises during the year ended December 31, 2022, was $0.1 million.

As of December 31, 2023, there was $3.7 million of total unrecognized compensation cost related to non-vested stock options granted to employees, which is expected to be recognized over a weighted-average period of 1.3 years.

Restricted Stock Units and Restricted Stock Awards

From time to time, upon approval by the Company’s board of directors, certain employees have been granted restricted stock units with time-based vesting criteria. The majority of these restricted stock units vest annually over a three-year or four-year term. In addition, pursuant to the Company’s director compensation policy, members of the Company’s board of directors have been granted, at their election, either restricted stock units or restricted stock awards, which awards vest annually over a three-year term with 33.33% vesting on each anniversary of the grant date. The fair value of restricted stock units and restricted stock awards are calculated based on the closing sale price of the Company’s common stock on the date of grant.

The Company has granted performance-based restricted stock units to management for which vesting occurs upon the achievement of certain clinical development milestones. Stock-based compensation expense associated with these performance-based restricted stock units is recognized when the achievement of the vesting conditions becomes probable. The Company did not recognize any stock-based compensation expense relating to the achievement of performance-based milestones during the year ended December 31, 2023.

As of December 31, 2023, there was $8.0 million of unrecognized stock-based compensation expense related to outstanding restricted stock units, with an expected recognition period of 1.85 years.

Stock-based Compensation Expense

The weighted‑average grant date fair value per share of options granted in the years ended December 31, 2023 and 2022 was $2.60 and $5.99, respectively.