Stock-Based Compensation

3 Months Ended

Mar. 31, 2025

Stock-Based Compensation [Abstract]

STOCK-BASED COMPENSATION

NOTE 9. STOCK-BASED COMPENSATION

As of March 31, 2025, 2,762,719 shares were reserved for issuance under the 2024 Equity Incentive Plan (the “2024 Plan”), of which 1,199,754 shares were available for future grant and 1,562,965 shares were subject to outstanding options and restricted stock units (“RSUs”), including performance-based awards of 65,894. As of March 31, 2025, options to purchase 143,835 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, 2025, 29,802 shares have been issued under the 2021 Employee Stock Purchase Plan (the “2021 ESPP”) and 18,630 shares under the 2024 Employee Stock Purchase Plan (the “2024 ESPP”). As of March 31, 2025, 1,000,000 shares were reserved under the 2024 ESPP and 981,370 shares were available for future issuance. As of March 31, 2025, 550,000 shares were reserved for issuance under the 2022 Inducement Equity Incentive Plan (the “2022 Inducement Plan”), of which 50,574 shares were available for future grant and 499,426 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, 2025:

	Options Outstanding			Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (in thousands)
Balance, December 31, 2024		1,628,378		$	19.79		8.31	$	6,608
Options granted		609,700		$	6.16
Options cancelled/forfeited		(51,852	)	$	16.12
Balance, March 31, 2025		2,186,226		$	16.08		8.20	$	—
Vested and expected to vest, March 31, 2025		2,186,226		$	16.08		8.20	$	—
Exercisable, March 31, 2025		737,799		$	20.29		7.18	$	—

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. The total intrinsic value of the options exercised during the three months ended March 31, 2024 was $0.4 million, and no options were exercised during the three months ended March 31, 2025.

The total fair value of options that vested during the three months ended March 31, 2025 and 2024 was $2.7 million and $1.7 million, respectively. The weighted-average grant date fair value of options granted during the three months ended March 31, 2025 and 2024 was $4.92 and $15.17 per share, respectively.

Unamortized stock-based compensation expense as of March 31, 2025 was $15.0 million, which is expected to be recognized over a weighted-average period of 2.9 years.

Performance-Based Stock Options 

There was no performance-based stock option activity under the 2024 Plan or the 2021 Plan for the three months ended March 31, 2025.

	Options Outstanding		Weighted Average Exercise Price		Weighted Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (in thousands)
Balance, December 31, 2024		45,894	$	13.95		6.04	$	438
Balance, March 31, 2025		45,894	$	13.95		5.80	$	—
Vested and expected to vest, March 31, 2025		45,894	$	13.95		5.80	$	—
Exercisable, March 31, 2025		30,893	$	7.33		5.18	$	—

Restricted Stock Units (RSUs)

As of March 31, 2025 and December 31, 2024, the Company had no unvested outstanding RSUs and no RSUs were granted during the three months ended March 31, 2025 and 2024.

Performance Restricted Stock Units (PSUs)

The following table provides a summary of PSU activity under the 2024 Plan during the three months ended March 31, 2025:

	Number of Share		Weighted- Average Grant Date Fair Value
Unvested performance-based restricted stock units at December 31, 2024		20,000	$	21.90
Granted		—	$
Unvested performance-based restricted stock units at March 31, 2025		20,000	$	21.90
Outstanding performance-based restricted stock units at March 31, 2025		20,000	$	21.90

In June 2024, the Company granted PSUs for 20,000 shares that will vest in full if the closing price of the Company’s common stock on the Nasdaq Capital Market reaches or exceeds $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 is not met within two years from the grant date, the PSUs will be forfeited. The Company concluded that issued PSUs are 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.

Employee Stock Purchase Plans

The Company issued no shares of common stock under the 2021 ESPP and the 2024 ESPP during each of the three months ended March 31, 2025 and 2024, and recognized $0.1 million and zero compensation expense related to the 2021 ESPP and the 2024 ESPP during the three months ended March 31, 2025 and 2024, respectively. There was no unamortized stock-based compensation for shares issuable under the 2021 ESPP as of March 31, 2025. There was $0.5 million unamortized stock-based compensation for shares issuable under the 2024 ESPP as of March 31, 2025, which is expected to be recognized over a weighted-average period of 1.3 years. The Company recorded $0.3 million in accrued expenses and other current liabilities related to contributions withheld as of March 31, 2025. 

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,
	2025		2024
General and administrative	$	1,240	$	820
Research and development		571		349
Total	$	1,811	$	1,169

The Company recognized zero and less than $0.1 million of stock-based compensation expense related to performance-based options and RSUs during the three months ended March 31, 2025 and 2024, 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,
	2025	2024
Expected term (in years)	6.01 – 6.08	6.04 – 6.08
Expected volatility	97.37% – 97.93%	112%
Risk-free interest rate	3.93% – 4.35%	3.93% – 4.27%
Expected dividend yield	—	—