Note 11: Stock-based Compensation

Stock Incentive Plans

On June 22, 2023, the Company’s stockholders approved the Company’s Amended and Restated 2017 Equity Incentive Plan (the “2017 Plan”), which amended and restated the Company’s 2017 Equity Incentive Plan, as amended, to (i) increase the number of shares of common stock authorized for issuance thereunder by 1,250,000 shares; (ii) limit the number of incentive stock options that can be granted under the plan to 7,738,761 shares of common stock; (iii) add an annual limit on non-employee director compensation, including cash and the value of equity awards, of $750,000 for incumbent directors and $1,000,000 in a director’s first year of service; and (iv) extend the term of the plan (including the duration of the evergreen) to 10 years from June 22, 2023, the date that stockholders approved the plan. In addition, the 2017 Plan provides for an annual increase to be added on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2024 and continuing for each fiscal year until, and including, the fiscal year ending December 31, 2033, equal to the lower of (i) 4% of the sum of (I) the number of outstanding shares of common stock on such date and (II) the number of shares of common stock issuable upon conversion of any outstanding shares of convertible preferred stock of the Company on such date (without giving effect to any restrictions or limitations on conversion) and (ii) an amount determined by the Company’s board of directors.

As of December 31, 2024, there were 244,003 shares of common stock available for grant under the 2017 Plan. On January 1, 2025, 554,663 shares of common stock were added and were available for grant under the 2017 Plan.

Under the plans, the Board or the compensation committee determines the number of shares of common stock to be granted pursuant to the awards, as well as the exercise price and terms of such awards. The exercise price of incentive stock options cannot be less than the fair value of the common stock on the date of grant. Stock options awarded under the plans expire 10 years after the grant date, unless the Board or the compensation committee sets a shorter term. Options granted under the plans generally vest over a four-year period. A portion of the unvested stock options will vest upon the sale of all or substantially all of the stock or assets of the Company.

Stock Option Awards

On May 1, 2023, the Company commenced a one-time stock option exchange program (the “Option Exchange Program”), under which the Company’s eligible executive officers, other employees and non-employee directors (collectively, “Eligible Holders”) were given the opportunity to exchange outstanding options to purchase shares of the Company’s common stock held by them for an equal number of RSUs that are subject to vesting conditions. The Option Exchange Program expired on May 30, 2023. A total of 36 Eligible Holders participated in the Option Exchange Program. Pursuant to the terms and conditions of the Option Exchange Program, the Company accepted for exchange options to purchase a total of 182,251 shares of the Company’s common stock. All surrendered options were cancelled effective as of the expiration of the Option Exchange Program, and immediately thereafter, in exchange therefor, the Company granted a total of 182,251 RSUs pursuant to the terms of the Option Exchange Program and the 2017 Plan. A de minimis number of eligible options were not surrendered for exchange and remain outstanding. Based upon the modification guidance under ASC 718, the Company is required to record an incremental compensation expense of $1,210, which will be recorded, along with the unrecognized compensation cost as of the date of the modification, over the remaining service period of the modified awards.

During the year ended December 31, 2024, the Company granted options for the purchase of 317,139 shares of common stock, including options to directors and inducement grant options to purchase 3,125 shares of common stock to a new employee made outside of the 2017 Plan in accordance with Nasdaq Listing Rule 5635(c)(4). During the year ended December 31, 2023, the Company granted options for the purchase of 666,962 shares of common stock, including options to directors and inducement grant options to purchase 13,920 shares of common stock to new employees made outside of the 2017 Plan in accordance with Nasdaq Listing Rule 5635(c)(4)

A summary of option activity is as follows:

Weighted

Weighted

Average

Average

Remaining

Aggregate

Number of

Exercise

Contractual

Intrinsic

    

Shares

    

Price

    

Term

    

Value

(Years)

(in thousands)

Outstanding as of January 1, 2024

670,064

$

15.93

9.4

$

Granted

317,139

6.92

Exercised

(1,281)

7.00

Forfeited

(107,919)

11.67

Outstanding as of December 31, 2024

878,003

$

13.22

8.6

$

23

Vested or expected to vest as of December 31, 2024

878,003

$

13.22

8.6

$

23

Options exercisable as of December 31, 2024

292,670

$

16.24

8.5

$

The Company records stock-based compensation related to stock options granted at fair value. The Company utilizes the Black-Scholes option-pricing model to estimate the fair value of stock option grants and to determine the related compensation expense. The assumptions used in calculating the fair value of stock-based payment awards represent management’s best estimates. The assumptions used in determining fair value of the stock options granted during the years ended December 31, 2024 and 2023 are as follows:

Year Ended December 31,

2024

2023

Expected volatility

107.9%

110.3%

108.4%

123.1%

Risk-free interest rate

3.46%

4.41%

3.55%

4.43%

Expected dividend yield

0%

0%

Expected term (in years)

5.50

6.07

5.50

6.10

The Company derived the risk-free interest rate assumption from the U.S. Treasury rates for U.S. Treasury zero-coupon bonds with maturities similar to those of the expected term of the awards being valued. The Company based the expected dividend yield on its expectation of not paying dividends in the foreseeable future. The Company calculated the expected term of options using the simplified method, as the Company lacks relevant historical data due to the Company’s limited operating experience. The expected volatility is based upon the historical volatility of the Company. The impact of forfeitures on compensation expense is recorded as they occur.

The weighted average grant-date fair value of options granted during the years ended December 31, 2024 and 2023, was $5.79 and $12.82, respectively. The fair value is being expensed over the vesting period of the options on a straight-line basis as the services are being provided. As of December 31, 2024, there was $5,828 of unrecognized compensation cost related to the stock options granted, which is expected to be expensed over a weighted-average period of 2.57 years. Stock-based compensation expense was classified in the consolidated statements of operations and comprehensive loss as follows:

Year Ended

December 31, 

2024

    

2023

Research and development

$

2,635

$

2,110

General and administrative

5,754

5,353

Total

$

8,389

$

7,463

During the year ended December 31, 2024, 1,281 options were exercised. There were no stock options exercised during the year ended December 31, 2023.

Restricted Stock Units—During the years ended December 31, 2024 and 2023, the Company issued 71,830 RSUs and 824,190 RSUs (which includes the RSUs issued in connection with the Option Exchange Program in 2023), respectively, to certain executives and other employees which will vest no sooner than one-third per year over three years on the anniversary of the date of grant.

As of December 31, 2024, a total of 564,323 RSUs were outstanding, consisting of 544,117 unvested shares and 20,206 vested and deferred shares by directors. This results in unrecognized stock-based compensation of $6,284 to be recognized as stock-based compensation expense over the remaining weighted-average vesting period of 1.28 years.

A summary of activity for RSUs for the year ended December 31, 2024 is as follows:

Weighted Average

Grant Date

Shares

Fair Value

Unvested and outstanding balance as of January 1, 2024

824,998

$

22.31

Changes during the period:

Granted

71,830

6.90

Vested

(266,770)

19.90

Forfeited

(85,941)

21.01

Unvested and outstanding balance as of December 31, 2024

544,117

$

21.67

Vested and deferred balance as of December 31, 2024

20,206

Employee Stock Purchase Plan—In 2017, the Company approved the 2017 Employee Stock Purchase Plan, which was amended and restated in December 2018 (as amended, the “ESPP”). The ESPP reserved an aggregate of 4,466 shares of common stock and provides for an annual increase on the first day of each fiscal year, beginning on January 1, 2019 and ending on December 31, 2029, in an amount equal to the lowest of: (1) 17,868 shares of the Company’s common stock; (2) 1% of the total number of shares of the Company’s common stock outstanding on the first day of the applicable fiscal year; and (3) an amount determined by the Company’s board of directors. On January 1, 2025, 17,868 shares of common stock were added and were available for grant under the ESPP.

The ESPP provides for two six-month offering periods each year: the first offering period begins on the first trading day on or after each January 1 and the second offering period begins on the first trading day on or after each July 1. Under the ESPP, participating employees can authorize the Company to withhold a portion of their base pay during consecutive six-month payment periods for the purchase of shares of the Company’s common stock. At the conclusion of the period, participating employees can purchase shares of the Company’s common stock at 85% of the lesser of the closing price of the common stock on (i) the first business day of the plan period or (ii) the exercise date. The fair value of the purchase rights granted under the ESPP was estimated on the date of grant, using the Black-Scholes option-pricing model. During the years ended December 31, 2024 and 2023, employees of the Company purchased an aggregate of 11,448 and 3,690 shares, respectively, under the ESPP.

About Stock Compensation Disclosures

Stock-based compensation disclosures detail the equity awards granted to employees and executives — including stock options, restricted stock units (RSUs), and performance shares — along with the valuation methods and assumptions used to expense them. This section reveals the true cost of talent retention and the alignment between management incentives and shareholder interests.

Key signals: total unrecognized compensation expense and its expected recognition period signal future earnings headwinds from already-granted awards. For stock options, examine Black-Scholes assumptions — expected volatility, risk-free rate, and expected term — as understating any of these reduces reported compensation expense. Compare stock compensation expense as a percentage of revenue against peers to assess dilution cost. Watch vesting schedules for acceleration clauses tied to change-of-control events. Performance-based awards with undemanding targets may indicate weak governance. Add back stock compensation to operating cash flow to calculate a more conservative free cash flow figure.