Stock-Based Compensation and Employee Benefit Plans
2020 Equity Incentive Plan
In September 2020, the Company adopted the 2020 Stock Incentive Plan (the “2020 Plan”) which, as of the adoption date, replaced the 2016 Stock Incentive Plan. Under the 2020 Plan, the share reserve automatically increases on January 1st of each year beginning in 2021 and ending with a final increase on January 1, 2030 in an amount equal to 4% of the Company’s outstanding shares of common stock on December 31st of the preceding calendar year. The Board may provide that there will be no increase in the share reserve for any such year or that the increase in the share reserve may be smaller than would otherwise occur. As of December 31, 2025, there were 3,741,270 shares of common stock available for future grants. On January 1, 2026, the share reserve automatically increased by 2,531,194 shares. The 2020 Plan permits the granting of options, stock appreciation rights, RSUs, performance stock, and performance cash awards. The terms of the agreements under the 2020 Plan are determined by the Board. The Company’s awards generally vest over four years and have a term of 10 years. Periodically, the Company also grants awards that vest based on the Company’s stock achieving certain closing share prices for a specified number of consecutive trading days.
2020 Employee Stock Purchase Plan
The 2020 Employee Stock Purchase Plan (the “2020 ESPP”) became effective in October 2020. Eligible employees may purchase shares of common stock under the 2020 ESPP at 85% of the lower of the fair market value of the Company’s common stock as of the first or the last day of each offering period. Employees are limited to contributing 15% of the employee’s eligible compensation and may not purchase more than $25,000 of stock during any calendar year or more than 600 shares during any one purchase period prior to December 31, 2024, and 2,000 shares for purchase periods beginning in 2025. The 2020 ESPP share reserve automatically increases on January 1st of each calendar year, for ten years, commencing on January 1, 2021, in an amount equal to 1% of the total number of shares of common stock outstanding on December 31st of the preceding calendar year. The Board may act prior to January 1st of a given year to provide that there will be no January 1st increase of the share reserve for such year or that the increase in the share reserve for such year will be a smaller number of shares of common stock than would otherwise occur pursuant to the preceding sentence. The Board elected not to increase the share reserve for the ESPP on January 1, 2026. As of December 31, 2025, there were 1,629,954 shares available for future purchases. During the years ended December 31, 2025 and 2024, the Company issued 30,275 and 17,246 shares, respectively, of common stock for aggregate cash proceeds of less than $0.1 million each year.
2025 Inducement Grants
In December 2025, the Company issued an inducement grant pursuant to the “inducement exception” provided under Nasdaq Listing Rule 5635(c)(4) (“inducement grants”) to a person not previously employed by the Company. The Company may issue additional inducement grants to non-employees or following a bona fide period of non-employment, as an inducement to such persons entering into employment with the Company. Inducement grants must be approved by the Company’s compensation committee, and consultants and directors are not eligible to receive inducement grants. Stock options issued as inducement grants generally vest over four years and have a term of 10 years.
The Company recorded stock-based compensation expense in the following expense categories of its accompanying statements of operations and comprehensive loss (in thousands):
Year Ended December 31,
20252024
Research and development$2,951 $4,894 
General and administrative4,044 4,652 
Total stock-based compensation$6,995 $9,546 
The following table summarizes option activity for the year ended December 31, 2025:
Options
Weighted
Average
Exercise Price
Weighted
Average
Remaining Life
(Years)
Balance at December 31, 2024
6,573,172 $7.19 6.90
Granted2,999,050 1.28
Exercised— — 
Forfeited(923,507)6.23
Balance at December 31, 2025
8,648,715 $5.25 7.06
Vested and expected to vest3,812,538 $2.77 8.87
Exercisable at the end of the period4,333,697 $7.53 5.37
Options granted during the years ended December 31, 2025 and 2024 had weighted-average grant-date fair values of $1.06 and $5.73 per share, respectively. As of December 31, 2025, the unrecognized compensation cost for options issued was $8.0 million and will be recognized over an estimated weighted-average amortization period of 1.17 years. There were no exercises for the year ended December 31, 2025, and the total intrinsic value of options exercised during the year ended December 31, 2024 was $1.7 million. The aggregate intrinsic value of options outstanding and exercisable as of December 31, 2025 was $1.4 million. The aggregate intrinsic value of options outstanding as of December 31, 2025 was $9.2 million.
Restricted Stock Units
The following table summarizes employee RSU activity for the year ended December 31, 2025:
Awards
Weighted
Average
Grant Date Fair Value
Unvested RSUs at December 31, 2024
817,350 $8.02 
Granted— — 
Vested(236,051)7.62 
Forfeited(100,122)8.36 
Balance at December 31, 2025
481,177 8.15 
The Company recognized $1.5 million and $2.2 million of stock-based compensation cost related to RSUs as of December 31, 2025 and 2024, respectively. As of December 31, 2025, the unrecognized compensation cost for RSUs issued was $2.4 million and will be recognized over an estimated weighted-average amortization period of 1.01 years. The fair value of RSUs is based on the fair value of the Company's common stock on the date of the grant.
Fair Value of Stock Options and Shares Issued
The Company accounts for stock-based compensation by measuring and recognizing as compensation expense the fair value of all share-based payment awards made to employees, including employee stock options and restricted stock awards. The Company uses the Black-Scholes option pricing model to estimate the fair value of employee stock options that only have service or performance conditions. The inputs to the pricing model require a number of management estimates such as the expected term, volatility, risk-free interest rate and dividend yield. The fair value of stock options was determined using the methods and assumptions discussed below.
The expected term of employee stock options with service-based vesting is determined using the “simplified” method, whereby the expected life equals the arithmetic average of the vesting term and the original contractual term of the option due to the Company’s lack of sufficient historical data.
The expected stock price volatility assumption is based on the historical volatilities of the common stock of a peer group of publicly traded companies as well as the historical volatility of the Company's common stock since the Company began trading subsequent to the Company’s initial public offering (“IPO”) in October 2020 over the period corresponding to the expected life as of the grant date. The historical volatility data was computed using the daily closing prices during the equivalent period of the calculated expected term of the stock-based awards. The Company will continue to apply this process until a sufficient amount of historical information regarding the volatility of the Company's stock price becomes available, or until circumstances change, such that the identified entities are no longer comparable companies. In the latter case, other suitable, similar entities whose share prices are publicly available would be utilized in the calculation.
The risk-free interest rate is based on the interest rate payable on U.S. Treasury securities in effect at the time of grant for a period that is commensurate with the expected term.
The expected dividend yield is 0% because the Company has not historically paid, and does not expect, for the foreseeable future, to pay dividends on its common stock.
Prior to the Company’s IPO, the Board periodically estimated the fair value of the Company’s common stock considering, among other things, contemporaneous valuations of its common stock prepared by an unrelated third-party valuation firm. Subsequent to the Company’s IPO, options are issued with a strike price no less than the market price on date of grant.
The grant-date fair value of options calculated using the Black-Scholes option pricing model granted under the Company’s 2020 Plan were estimated using the following weighted-average assumptions:
Year Ended December 31,
20252024
2020 Plan
Expected term - years5.966.02
Expected volatility102.9 %97.4 %
Risk-free interest rate4.3 %4.2 %
Expected dividends$— $— 
The grant-date fair value of shares issued calculated using the Black-Scholes option pricing model under the Company’s 2020 ESPP were estimated using the following weighted-average assumptions:
Year Ended December 31,
20252024
2020 ESPP
Expected term - years0.50.5
Expected volatility105.2 %115.1 %
Risk-free interest rate4.2 %5.1 %
Expected dividends$— $— 
Employee Benefit Plans
The Company sponsors a 401(k) retirement plan in which substantially all of its full-time employees are eligible to participate. Participants may contribute a percentage of their annual compensation to this plan, subject to statutory limitations. The Company made matching contributions of $0.4 million and $0.6 million to the plan for the years ended December 31, 2025 and 2024, respectively.

Historical Timeline

Fiscal YearFiled
2025Mar 5, 2026Showing above
2024Mar 27, 2025

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.