13. Stock-Based Payments

2016 Stock Incentive Plan

The 2016 Stock Incentive Plan (the “2016 Plan”) 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 Company’s initial public offering (“IPO”). The 2016 Plan replaced the 2012 Equity Incentive Plan (the “2012 Plan”). Any options or awards outstanding under the 2012 Plan remained outstanding and effective. The 2016 Plan was replaced by 2022 Equity Incentive Plan on September 16, 2022, and no further awards may be made under the 2016 Plan.

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, 2022, the number of shares reserved for issuance under the 2016 ESPP was increased by 62,024 shares. At December 31, 2022, 237,169 shares remained available for future issuance under the 2016 ESPP.

Inducement Grants

During the year ended December 31, 2021, the Company granted non-statutory stock options to purchase an aggregate of 111,000 shares of the Company’s common stock. These stock options were granted outside of the 2016 Plan as an inducement material to the applicable employee’s acceptance of employment with the Company in accordance with Nasdaq Listing Rule 5635(c)(4).These stock options will vest over a four-year period, with 25% of the shares underlying each option award vesting on the one-year anniversary of the applicable employee’s employment commencement date and the remaining 75% of the shares underlying each award vesting monthly thereafter for three-years. Vesting of each option is subject to such employee’s continued service with the Company through the applicable vesting dates.

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 with respect to an aggregate of 100,000 shares of common stock. 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). At December 31, 2022, 22,443 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. 4,737,534 shares of the Company’s common stock are reserved for issuance under the 2022 EIP. At December 31, 2022, 1,991,628 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 stock options to management for which vesting accelerates upon the achievement of performance-based criteria. Milestone events are specific to the Company’s corporate goals, including but not limited to certain clinical development milestones and the Company’s ability to execute on its corporate development and financing strategies. Stock-based compensation expense associated with these performance-based stock options is recognized based on the accelerated attribution model. Management evaluates when the achievement of a performance-based milestone is probable based on the expected satisfaction of the performance conditions as of the reporting date. Notwithstanding any vesting in accordance with the achievement of performance-based milestones, such awards vest in full on the sixth anniversary of the vesting commencement date. During the year ended December 31, 2020, the Company recorded additional stock-based compensation expense of $0.4 million related to the acceleration of vesting of certain stock options associated with the initiation of the Phase 3 clinical trial of tamibarotene at the end of 2020 and the entry into the GBT Collaboration Agreement in December 2019, respectively. As of December 31, 2020, there was no unrecognized expense related to the performance-based stock options granted to management. The Company did not grant any performance-based stock option to management during the years ended December 31, 2022 and 2021.

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, 2022, there was $0.3 million of unrecognized compensation cost related to this option, with a remaining contractual period of 3.7 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.

The intrinsic value of stock options exercised during the years ended December 31, 2022, 2021 and 2020 was $0.1 million, $0.1 million and $0.8 million, respectively.

As of December 31, 2022, there was $9.7 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 2.2 years.

Cash received from option exercises during the years ended December 31, 2022, 2021, and 2020 was $0.1 million, $0.2 million, and $1.1 million, respectively.

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 four-year term with 25% vesting on each anniversary of the grant date. In addition, pursuant to our director compensation policy, members of our 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.

As of December 31, 2022, there was $12.7 million of unrecognized stock-based compensation expense related to outstanding restricted stock units, with an expected recognition period of 2.06 years.

Stock-based Compensation Expense

The weighted‑average grant date fair value per share of options granted in the years ended December 31, 2022, 2021 and 2020 was $5.99, $53.30 and $53.00, respectively.

Due to an operating loss, the Company does not record tax benefits associated with stock‑based compensation or option exercises. Tax benefits will be recorded when realized.