The Company has classified equity-based compensation expense in its condensed consolidated statements of operations as follows:


	Three Months Ended March 31,
	2025		2024
Research and development	$	1,102	$	548
General and administrative		2,239		1,063
Total	$	3,341	$	1,611

As of March 31, 2025, the Company’s approved equity incentive plans include: the 2018 Omnibus Incentive Plan (the "2018 Plan"); Amended and Restated 2020 Equity Incentive Plan, as amended (the "2020 Plan"); the Amended and Restated 2021 Employee Stock Purchase Plan; and the 2024 Inducement Stock Incentive Plan (the "2024 Plan"). These plans are administered by the Board of Directors (the "Board") and permit the granting of stock options, stock appreciation rights, restricted stock, restricted stock units (the "RSUs"), performance awards, and other stock‑based or cash-based awards. Upon the adoption of the 2020 Plan, the Company no longer grants new equity awards under its 2018 Plan.

On June 11, 2024, the Company's stockholders approved an amendment to the 2020 Plan to increase the number of shares of common stock reserved for issuance under the plan by 2,000,000 shares. As of March 31, 2025, there were 1,953,279 stock options outstanding, 2,637,437 RSUs outstanding, 2,165,325 performance stock units outstanding, and 384,858 shares remained available for future issuance under the 2020 Plan.

In March 2024, the Board approved the 2024 Plan, which provides for the reservation of 1,000,000 shares of common stock for equity granted as an inducement material to the individual’s entering into employment with the Company and in accordance with the requirements of Nasdaq Stock Market Rule 5635(c)(4). As of March 31, 2025, there were 100,000 stock options outstanding, 354,965 RSUs outstanding, and 545,035 shares remained available for future issuance under the 2024 Plan.

The table below summarizes the activity with respect to stock options for the three months ended March 31, 2025:


	Number of Options			Weighted Average Exercise Price		Remaining Contractual Life (in years)		Aggregate Intrinsic Value
Outstanding at January 1, 2025		2,927,937		$	18.22		8.01	$	193
Granted		22,148		$	4.10
Exercised		—		$	—
Expired		(70,538	)	$	114.73
Forfeitures		(29,106	)	$	4.99
Outstanding at March 31, 2025		2,850,441		$	15.86		7.93	$	140
Vested and expected to vest as of March 31, 2025		2,850,441		$	15.86		7.93	$	140
Exercisable at March 31, 2025		1,339,029		$	25.71		7.19	$	51

The assumptions used in the Black-Scholes option-pricing model for all stock options granted during each period presented are as follows:


	Three Months Ended March 31,
	2025	2024
Common stock price	$4.10	$5.76-$7.85
Expected volatility	112.1%	123.8% - 128.7%
Expected dividends	0.0%	0.0%
Expected term (in years)	5.31	5.31 - 6.25
Risk-free rate	4.4%	3.8% - 4.3%

The weighted average grant date fair values of stock options granted during the three months ended March 31, 2025 and 2024 were $3.39 and $7.03, respectively.

The Company recognized $1.3 million and $0.9 million of equity-based compensation expense in connection with stock options during the three months ended March 31, 2025 and 2024, respectively. As of March 31, 2025, there was $7.6 million of total unrecognized equity-based compensation expense related to unvested stock options, which is expected to be recognized over a weighted average period of 2.0 years.

The following table summarizes activity with respect to RSUs during the three months ended March 31, 2025:


	Units			Weighted- Average Grant Date Fair Value
Nonvested RSUs at January 1, 2025		1,480,272		$	7.50
Granted		2,029,332		$	3.20
Vested		(247,970	)	$	7.72
Forfeitures		(86,966	)	$	5.02
Nonvested RSUs at March 31, 2025		3,174,668		$	4.81

The Company recognized $1.0 million and $0.7 million of equity-based compensation expense in connection with RSUs during the three months ended March 31, 2025 and 2024, respectively. As of March 31, 2025, there was $14.0 million of total unrecognized equity-based compensation expense related to nonvested RSUs, which is expected to be recognized over a weighted average period of 3.4 years.

In June 2024, the Board approved a grant of performance-based restricted stock unit awards ("PSUs" or "Performance Awards") to the Company’s executive team. Each PSU represents the contingent right to receive one share of the Company’s common stock. These Performance Awards provide for the vesting of 25% of the target number of underlying RSUs granted upon the achievement of each of four independent performance milestones predetermined by the Board ("Performance Milestones"), subject to the grantee’s continued service with the Company (the "Approval Conditions").

The Performance Milestones are tied to the achievement of certain business objectives and are non-market and non-financial in nature. The Board will determine that all Approval Conditions have been satisfied and the number of units that will ultimately vest on the 2026 Evaluation Date, which will occur in the first quarter of 2026, and the 2027 Evaluation Date, which will occur in the first quarter of 2027. A maximum of 25% of the target number of RSUs may vest at the 2026 Evaluation Date and the percentage of the target number of RSUs allocable to any Performance Milestone that has not been achieved on or prior to the 2027 Evaluation Date shall be cancelled.

The following table summarizes activity with respect to PSUs during the three months ended March 31, 2025:


	Units		Weighted- Average Grant Date Fair Value
Nonvested PSUs at January 1, 2025		2,165,325	$	7.51
Granted		—	$	—
Vested		—	$	—
Forfeitures		—	$	—
Nonvested PSUs at March 31, 2025		2,165,325	$	7.51

The Company recognized $1.0 million of equity-based compensation expense in connection with PSUs during the three months ended March 31, 2025. No equity based-compensation expense was recognized in connection with PSUs during the three months ended March 31, 2024.

As of March 31, 2025, there was $5.0 million of unrecognized equity-based compensation expense related to nonvested PSUs based on the achievement of all Performance Milestones, which is expected to be recognized over a weighted average period of 1.6 years.