Stock-based compensation expense recorded in the condensed consolidated statements of operations and comprehensive loss is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2026		2025		2026		2025
Research and development expenses	$	2,350	$	2,141	$	4,540	$	4,507
General and administrative expenses	2,800		2,907		5,354		5,628
Total	$	5,150	$	5,048	$	9,894	$	10,135

The following table presents, on a weighted-average basis, the assumptions used in the Black-Scholes option-pricing model to determine the fair value of stock options granted during the six months ended June 30, 2026 and 2025:


	June 30, 2026		June 30, 2025
Risk‑free interest rate	3.68	%	4.04	%
Expected volatility	85	%	78	%
Expected dividend yield	—		—
Expected term (in years)	6.01		6.00

The following table summarizes the Company's stock option activity during the six months ended June 30, 2026:


	Number of Shares	Weighted‑ Average Exercise Price

Outstanding as of December 31, 2025	5,960,989	$	11.73
Granted	883,600	11.16
Exercised	(27,027)	4.83
Forfeited	(49,314)	13.71
Outstanding as of June 30, 2026	6,768,248	$	11.67
Exercisable as of June 30, 2026	4,932,674	$	11.64

The weighted-average grant-date fair value of stock options granted during the six months ended June 30, 2026 and 2025 was $8.18 per share and $7.90 per share, respectively. As of June 30, 2026, there was $14.2 million of unrecognized compensation cost related to unvested stock options, which is expected to be recognized over a weighted-average period of 2.8 years.

During the six months ended June 30, 2026, restricted stock units ("RSUs") were granted to employees with vesting conditions based on continued service over time. Accordingly, stock-based compensation expense for such awards is recognized using a straight-line attribution model over the vesting term of each RSU. The fair value of each RSU is based on the closing price of the Company's common stock on the date of grant.

A summary of restricted stock activity during the six months ended June 30, 2026 is as follows:


	Shares	Weighted‑ Average Grant‑Date Fair Value
Unvested as of December 31, 2025	2,284,277	$	12.76
Granted	1,229,730	$	11.28
Vested	(568,270)	$	12.78
Forfeited	(66,052)	$	13.06
Unvested as of June 30, 2026	2,879,685	$	12.12

As of June 30, 2026, there was $29.6 million of unrecognized stock-based compensation expense related to restricted stock that is expected to vest. These costs are expected to be recognized over a weighted-average remaining vesting period of 2.7 years.

As of June 30, 2026 and December 31, 2025, there were 215,000 and 438,500 performance stock units ("PSUs") outstanding, respectively. The PSUs will vest upon achievement of certain clinical milestones and continued employment thereafter.

As of June 30, 2026, no PSUs have vested and no stock-based compensation expense has been recognized as the performance condition was not deemed probable. As of June 30, 2026, there was $3.2 million of unrecognized stock-based compensation expense related to unvested PSUs.