As of June 30, 2025, there is an aggregate of approximately 0.2 million shares of common stock available for issuance under the Company’s equity incentive plans, including 0.1 million shares of common stock remain available for issuance under the Amended and Restated 2017 Employee Stock Purchase Plan (the “2017 ESPP”).

Stock Option Valuation— The following table presents, on a weighted average basis, the assumptions used in the Black-Scholes option-pricing model to determine the grant-date fair value of stock options granted:


	Three Months Ended June 30,				Six Months Ended June 30,
	2025		2024		2025		2024
Risk-free interest rate	4.0	%	4.4	%	4.2	%	4.2	%
Expected term (in years)	6.1		6.1		6.1		6.1
Expected volatility	103.7	%	96.5	%	103.8	%	96.0	%
Expected dividend yield	0	%	0	%	0	%	0	%

The following table summarizes the Company’s stock option activity for the six months ended June 30, 2025:


	Number of Shares	Weighted Average Exercise Price		Weighted Average Contractual Term (Years)	Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2024	394,493	$	57.09	8.6	$	269
Granted	33,185	9.87

Forfeited and expired	(120,053)	33.42			$	—
Outstanding as of June 30, 2025	307,625	$	61.24	8.2	$	—
Exercisable as of June 30, 2025	121,016	$	112.56	6.9	$	—
Vested and expected to vest as of June 30, 2025	264,099	$	67.02	7.9	$	—

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock to the extent the stock option had a lower exercise price. There were no options exercised in 2025 and 2024. The weighted average grant-date fair value per share of stock options granted during the six months ended June 30, 2025 and 2024 was $8.13 and $25.80, respectively.

During the six months ended June 30, 2025, the Company granted 0.3 million time-based restricted stock units to employees at the grant date fair value of $12.65 per share. These awards vest as the employee provides services to the Company over a three-year vesting period. Also during the six months ended June 30, 2025, 0.1 million outstanding performance-based restricted stock units (“PRSUs”) vested based on the achievement of an operational milestone. The Company considers the achievement of the remaining operational milestone related to outstanding PRSUs to be probable. Stock-based compensation expense has been recognized for these awards using the accelerated attribution model based on the fair value of the awards as of the date of

grant and management’s best estimate of the date the probable operational milestone will be achieved. The Company updates its estimates related to the probability and timing of achievement of the operational milestones each period until the award either vests or is forfeited.

Stock-Based Compensation— As of June 30, 2025, total unrecognized compensation expense related to unvested stock options and restricted stock units was $5.5 million, which is expected to be recognized over a weighted average period of 2.3 years.

Stock-based compensation expense was classified in the condensed consolidated statements of operations and comprehensive(loss) income as follows:


	Three Months Ended June 30,				Six Months Ended June 30,
(in thousands)	2025		2024		2025		2024
Research and development expense	$	340	$	1,182	$	599	$	1,965
Selling, general and administrative expense	408		1,246		668		2,202
Total stock-based compensation	$	748	$	2,428	$	1,267	$	4,167

The following table summarizes the Company’s stock appreciation right (“SARs”) balances as of June 30, 2025 and December 31, 2024; there were no SARs granted, exercised or forfeited for the six months ended June 30, 2025. The weighted average target price of the SARs is $45.71. The settlement value is based on the difference between the closing price of the Company’s common stock on the date of settlement less the measurement price multiplied by the number of SARs exercised. The SARs vest and become exercisable in equal annual installments on the first, second, and third anniversaries of the Grant Date, subject to the recipient remaining an employee of the Company through and including each applicable vesting date.