Effective January 1, 2024, the number of shares of common stock available under the 2021 Equity Incentive (the “2021 Plan”) Plan increased by 1,798,926 shares pursuant to the evergreen provision. As of March 31, 2024, 770,983 shares of common stock remained available for issuance under the 2021 Plan. Effective January 1, 2024, the number of shares of common stock available under the 2021 Employee Stock Purchase Plan (the "ESPP") increased by 359,785 shares pursuant to the evergreen provision of the ESPP. As of

March 31, 2024, 811,671 shares of common stock remained available for issuance under the ESPP. As of March 31, 2024, 1,993,000 shares of common stock remained available for issuance under the 2023 Inducement Equity Plan as adopted in November 2023.

Total stock-based compensation expense related to the Company’s equity incentive plan and employee stock purchase plan was recorded in the statements of operations and allocated as follows (in thousands):


	Three Months Ended
	March 31,
	2024		2023
Research and development	$	2,546	$	1,474
General and administrative		2,476		1,759
Total stock-based compensation expense	$	5,022	$	3,233

As of March 31, 2024, there was $42.9 million of total unrecognized stock-based compensation expense which is expected to be recognized over a weighted-average period of 2.6 years.

The following table summarizes stock option activity:


	Outstanding Options
	Shares			Weighted- Average Exercise		Weighted- Average Remaining Contractual Term (Years)
Balance, December 31, 2023		7,357,607		$	9.34		8.1
Granted		1,838,510			14.60
Exercised		(22,750	)		5.09
Cancelled		(4,082	)		9.61
Balance, March 31, 2024		9,169,285			10.40		8.3
Exercisable, March 31, 2024		4,020,182		$	9.08		7.6

The following table summarizes the restricted stock activity:


	Number of Restricted Stock Awards			Weighted-Average Grant Date Fair Value
Balance, December 31, 2023		111,920		$	4.06
Granted		—			—
Released		(44,226	)		4.03
Forfeited		(2,564	)		3.96
Balance, March 31, 2024		65,130		$	4.09