In 2015, the Company's board of directors adopted the 2015 Equity Incentive Plan, as amended in 2018, 2019 and 2020 (the “2015 Plan”), which provided for the grant of incentive stock options, nonqualified stock options or other awards including stock appreciation rights and restricted stock awards to the Company’s employees, officers, directors, advisors, and consultants. In May 2020, the board of directors adopted the 2020 Stock Option and Incentive Plan (the “2020 Plan”) and suspended the 2015 Plan. Awards outstanding under either the 2015 Plan or 2020 Plan that are cancelled, expire or otherwise terminated subsequent to May 2020 will become available for issuance as common stock under the 2020 Plan. Additionally, the 2020 Plan is subject to automatic increases on January 1 of each year beginning January 1, 2021. The number of shares added each January 1 will be equal to the lesser of: (i) 5% of the outstanding shares on the immediately preceding December 31 or (ii) such amount as determined by the compensation committee of the board of directors.

The 2020 Plan provides for the grant of incentive stock options, nonqualified stock options or other awards including stock appreciation rights, restricted stock awards and restricted stock units to the Company’s employees, officers, directors, advisors and consultants.

In 2022, the board of directors adopted the 2022 Inducement Plan (the “2022 Plan”), under which the Company may grant nonqualified stock options or other awards including stock appreciation rights and restricted stock awards.

Options under the 2020 Plan and Inducement Plan may be granted for periods of up to 10 years and at prices no less than the market price of the Company’s common stock on the date of grant, provided, however, that the exercise price of an incentive stock option granted to a 10% shareholder shall not be less than 110% of the fair value of the shares on the date of grant and the option is not exercisable after the expiration of five years from the date of grant.

On April 15, 2026, upon the recommendation of its Compensation Committee, the Board approved an option repricing (the “Repricing”), effective as of April 17, 2026 (the “Effective Date”). The Repricing was undertaken in accordance with, and as permitted by, the Company’s 2015 Plan, 2020 Plan, and 2022 Plan. Pursuant to the Repricing, effective as of the Effective Date, all outstanding vested and unvested options originally granted on or before March 1, 2025 pursuant to the 2015 Plan, the 2020 Plan, or the 2022 Plan that are held by employees as of the Effective Date, including the Company’s executive officers, were repriced to reduce the exercise price to $1.33 per share, the closing price per share of the Company’s common stock on the Effective Date. No other changes were made to the terms and conditions of the eligible stock option awards.

In order to exercise the repriced options at the $1.33 per share exercise price, employees are required to remain in service with the Company through the Retention Period, which begins on the Effective Date and ends on the earliest of the following: (i) the 18-month anniversary following the Effective Date if the employee is a member of the Company’s executive leadership team, or the 12-month anniversary following the Effective Date for all other employees; (ii) the consummation of a Corporate Transaction (as defined by the 2015 Plan); (iii) the consummation of a Sale Event (as defined by the 2020 Plan and 2022 Plan); and (iv) the employee’s (a) termination by the Company without cause (as defined in the Eligible Participant’s applicable severance plan) or due to a reduction in force, (b) death or termination due to disability, or (c) if the employee is a Vice President or above, resignation from service for good reason (as defined in the Eligible Participant’s applicable severance plan).

The repriced options will be subject to the original exercise price that was in effect immediately prior to the Effective Date if the employee (i) is terminated by the Company for cause (as defined in the Eligible Participant’s applicable severance plan); (ii) resigns from the Company prior to the end of the applicable Retention Period, except for good reason (as defined in the Eligible Participant’s applicable severance plan) if the employee is a Vice President or above; or (iii) elects to exercise the repriced options prior to the end of the applicable Retention Period.

Stock options issued under either the 2015 Plan, the 2020 Plan or the Inducement Plan generally vest over four years and expire ten years from the date of grant. Certain options provide for accelerated vesting if there is a change in control, as defined in the respective plans.


	Three Months Ended June 30,		Six Months Ended June 30,
	2026	2025	2026	2025
Expected volatility	83.22% - 85.89%	88.02% - 89.30%	83.22% - 87.39%	86.82% - 89.30%
Risk-free interest rate	4.16% - 4.21%	3.98% - 4.12%	3.91% - 4.21%	3.98% - 4.45%
Expected dividend	—	—	—	—
Expected term (in years)	5.31 - 6.06	5.34 - 6.07	5.31 - 6.06	5.34 - 6.08
Underlying common stock fair value	$1.14	$1.37 - $1.61	$1.14 - $1.30	$1.37 - $12.63


	Number of Options	Weighted- Average Exercise Price per Share		Weighted- Average Remaining Contractual Term (in Years)	Aggregate Intrinsic Value
Outstanding as of December 31, 2025	7,456,066	$	15.28	5.60	$	—
Granted	5,117,500	$	1.29
Exercised	—	$	—
Forfeited	(1,004,547)	$	13.91
Outstanding as of June 30, 2026	11,569,019	$	9.21	7.26	$	—
Exercisable as of June 30, 2026	5,677,190	$	14.28	5.43	$	—
Vested and expected to vest as of June 30, 2026	11,569,019	$	9.21	7.26	$	—

As of June 30, 2026, there was $18.6 million of unrecognized compensation costs, inclusive of the incremental cost of repriced options, that are expected to be recognized over a weighted-average period of 2.23 years related to stock options. Aggregate intrinsic value represents the difference between the fair value of the underlying common stock and the exercise price as of June 30, 2026.


	Restricted Stock Units	Weighted Average Grant Date Fair Value
Unvested and outstanding as of December 31, 2025	858,247	$	16.04
Granted	107,751	$	1.30
Released	(405,212)	$	19.94
Forfeited	(36,072)	$	5.71
Unvested and outstanding as of June 30, 2026	524,714	$	10.70

In June 2020, the Company adopted the Company's 2020 Employee Stock Purchase Plan (the “2020 ESPP”). The 2020 ESPP provides that the number of shares reserved and available for issuance will automatically increase on January 1 of each calendar year, beginning January 1, 2021, by the least of (1) 1.0% of the total number of shares of common stock outstanding on December 31 of the preceding calendar year, (2) 700,000 shares or (3) such lesser amount as determined by the administrator of the 2020 ESPP, which is the compensation committee of the board of directors of the Company.

Under the 2020 ESPP, eligible employees may purchase shares of our common stock through payroll deductions that cannot exceed 15% of each employee’s salary. The 2020 ESPP provides for a six-month offering period. At the end of the purchase period, eligible employees are permitted to purchase shares of common stock at the lower of 85% of the fair market value at the beginning of the offering period or 85% of the fair market value at the end of the purchase period, subject to tax limitations on the total value of the purchase. The 2020 ESPP is considered a compensatory plan, and the Company recorded $27.5 thousand in stock-based compensation expense for the six months ended June 30, 2026 and $118.2 thousand for the six months ended June 30, 2025. During the six months ended June 30, 2026, 65,652 shares of common stock were issued, under the 2020 ESPP with 1,626,484 shares remaining available for issuance as of June 30, 2026. The Company used Black-Scholes option pricing model to estimate stock-based compensation expense for the 2020 ESPP with the following assumptions:


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Stock options and ESPP	$	3,259	$	4,406	$	6,387	$	10,367
Restricted stock units	927		1,976		2,053		4,927
Total stock-based compensation expense	$	4,186	$	6,382	$	8,440	$	15,294
Research and development expenses	$	1,464	$	1,935	$	3,191	$	5,637
General and administrative expenses	$	2,722	$	4,447	$	5,249	$	9,657