Stock-Based Compensation

3 Months Ended

Mar. 31, 2026

Stock-Based Compensation [Abstract]

STOCK-BASED COMPENSATION

NOTE 10. STOCK-BASED COMPENSATION

As of March 31, 2026, 2,750,719 shares were reserved for issuance under the 2024 Equity Incentive Plan (the “2024 Plan”), of which 418,817 shares were available for future grant and 2,331,902 shares were subject to outstanding options and restricted stock units (“RSUs”), including 30,894 shares subject to performance-based awards. As of March 31, 2026, options to purchase 140,516 shares of common stock remained outstanding and unexercised, and continue to be governed by the 2019 Equity Incentive Plan (the “2019 EIP”). As of March 31, 2026, 1,000,000 shares were reserved under the 2024 Employee Stock Purchase Plan (the “ESPP”), of which 920,827 shares were available for future issuance and 79,173 shares had been issued. As of March 31, 2026, 550,000 shares were reserved for issuance under the 2022 Inducement Equity Incentive Plan (the “2022 Inducement Plan”), of which 180,960 shares were available for future grant and 369,040 shares were subject to outstanding stock options.

Stock Option Activity

The following table summarizes the stock option activities, including performance-based stock options, under the 2024 Plan, the 2021 Equity Incentive Plan (the “2021 Plan”), the 2022 Inducement Plan and the 2019 EIP for the three months ended March 31, 2026:

	Options Outstanding			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (in thousands)
Balance, December 31, 2025		2,246,206		$	13.72		4.81	$	—
Options granted		1,262,300			1.65
Options cancelled/forfeited		(837,148	)		7.08
Balance, March 31, 2026		2,671,358			10.10		7.43		—
Vested and expected to vest, March 31, 2026		2,671,358			10.10		7.43		—
Exercisable, March 31, 2026		1,018,023			18.93		4.33		—

The aggregate intrinsic value represents the difference between the estimated fair value of the underlying common stock and the exercise price of outstanding, in-the-money options. No options were exercised during the three months ended March 31, 2026 and 2025.

The total fair value of options that vested during the three months ended March 31, 2026 and 2025 was $0.9 million and $2.7 million, respectively. The weighted-average grant date fair value of options granted during the three months ended March 31, 2026 and 2025 was $1.33 and $4.92 per share, respectively.

Unamortized stock-based compensation expense as of March 31, 2026 was $5.6 million, which is expected to be recognized over a weighted-average period of 3.0 years.

Performance-Based Stock Options 

There was no performance-based stock option activity under the 2024 Plan or the 2021 Plan during the three months ended March 31, 2026.

	Options Outstanding		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value  (in thousands)
Balance, December 31, 2025		30,894	$	7.33		4.43	$	—
Balance, March 31, 2026		30,894	$	7.33		4.18	$	—
Vested and expected to vest, March 31, 2026		30,894	$	7.33		4.18	$	—
Exercisable, March 31, 2026		30,894	$	7.33		4.18	$	—

Restricted Stock Units (RSUs)

The following table provides a summary of RSU activity under the 2024 Plan during the three months ended March 31, 2026:

	Number of Share			Weighted- Average Grant Date Fair Value
Unvested restricted stock units at December 31, 2025		198,900		$	6.00
Forfeited		(28,800	)	$	6.00
Unvested restricted stock units at March 31, 2026		170,100		$	6.00

Performance Restricted Stock Units (PSUs)

 In June 2024, the Company granted PSUs for 20,000 shares that would vest in full if the closing price of the Company’s common stock on the Nasdaq Capital Market reached or exceeded $35.00 per share (subject to adjustment for recapitalizations, stock splits and similar transactions) for thirty consecutive calendar days within two years from the grant date. If the vesting condition was not met within two years from the grant date, the PSUs would be forfeited. The Company concluded that issued PSUs were equity-based awards and include a market based vesting condition. The Company used a Monte Carlo simulation model to estimate the fair value of the PSUs with the following assumptions: common stock fair value of $23.95, which was the closing market price of the Company’s common stock at the grant date, volatility of 133.00%, risk free rate of 4.87%, and vesting term of 2.0 years. Total estimated fair value of $0.4 million was recognized as stock-based compensation expense over 0.4 years, the derived requisite service period from the grant date.

In January 2026, the employee holding the PSUs was terminated and the award was forfeited. No stock-based compensation expense was reversed upon forfeiture, as the award included only a market-based vesting condition and the derived requisite service period had been completed.

Employee Stock Purchase Plan

The Company did not issue any shares of common stock under the ESPP during the three months ended March 31, 2026 and 2025, and recognized less than $0.1 million and $0.1 million compensation expense related to the ESPP during the three months ended March 31, 2026 and 2025, respectively. There was $0.2 million unamortized stock-based compensation for shares issuable under the ESPP as of March 31, 2026, which is expected to be recognized over a weighted-average period of 1.7 years. The Company recorded $0.1 million in accrued expenses and other current liabilities related to contributions withheld as of March 31, 2026. 

Stock-Based Compensation Expense

The following table presents stock-based compensation expenses related to options, PSUs and RSUs granted to employees and non-employees, employee stock purchase plan awards and restricted common stock shares issued to founders (in thousands):

	Three Months Ended March 31,
	2026		2025
General and administrative	$	202	$	1,240
Research and development		221		571
Total	$	423	$	1,811

The Company recognized $0.1 million and zero stock-based compensation expense related to performance-based options, PSUs and RSUs during the three months ended March 31, 2026 and 2025, respectively.

Valuation of Stock Options

The grant date fair value of stock options was estimated using a Black-Scholes option-pricing model with the following assumptions:

	Three Months Ended March 31,
	2026			2025
Expected term (in years)		6.08			6.01 – 6.08
Expected volatility		99.87% – 100.05	%		97.37% – 97.93	%
Risk-free interest rate		3.85%  – 3.88	%		3.93% – 4.35	%
Expected dividend yield		—			—