The Company maintains three equity compensation plans; the 2020 Stock Plan, or the 2020 Plan, the 2022 Stock Option and Incentive Plan, or the 2022 Plan, and the 2022 Employee Stock Purchase Plan, or the ESPP. As of the Company's IPO in May 2022, the Company's board of directors determined that no further awards would be made under the 2020 Plan. The number of shares of common stock that may be issued under the 2022 Plan is subject to increase by the number of shares under any outstanding stock options forfeited and not exercised under the 2020 Plan. Additionally, the number of shares reserved for issuance under the 2022 Plan automatically increases on the first day of each fiscal year in an amount equal to the lower of (1) 5% of the shares of common stock outstanding on such date and (2) an amount determined by the Company’s board of directors. The 2022 Plan allows the board of directors to grant incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units, unrestricted stock awards, cash-based awards, and dividend equivalent rights to the Company’s officers, employees, directors and other key persons. As of June 30, 2024, 968,289 shares remained available for grant under the 2022 Plan and 421,924 shares remained available for issuance under the ESPP.

Stock option activity under the 2020 Plan and the 2022 Plan, is as follows:


	Stock Options			Weighted-Average Exercise Price
Outstanding as of December 31, 2023		4,233,203		$	10.83
Granted		1,474,417		$	15.68
Exercised		(164,548	)	$	10.93
Canceled/Forfeited		(264,097	)	$	12.98
Outstanding as of June 30, 2024		5,278,975		$	12.07

The weighted-average grant date fair value of options granted during the six months ended June 30, 2024 was $11.24 per share. The Company had 5,278,975 unvested stock options outstanding as of June 30, 2024. As of June 30, 2024, total unrecognized compensation cost related to stock options was $31.3 million. This amount is expected to be recognized over a weighted average period of approximately 2.68 years.

A restricted stock unit, or RSU, represents the right to receive one share of common stock upon vesting of the RSU. In February 2024, the Company granted employees a one-time RSU award that vests fully on the one-year anniversary of the grant date, provided that the employee remains employed with the Company. Certain employees, including employees who are executive officers of the Company, received a one-time RSU award that vests upon the achievement of certain performance-based clinical development milestones, or PSUs. Such awards cannot vest in less than one year, regardless of when the performance milestone is achieved. The Company’s chief executive officer did not receive any RSU or PSU awards. A summary of the Company’s RSU and PSU activity and related information for the six months ended June 30, 2024 is as follows:


	Time-based RSUs			PSUs		Weighted-Average Grant Date Fair Value
Outstanding as of December 31, 2023		—			—	$	—
Granted		77,645			28,555		10.64
Vested		—			—		—
Forfeited		(2,460	)		—		10.64
Issued and unvested as of June 30, 2024		75,185			28,555	$	10.64

The weighted average grant date fair value of the time-based RSUs and the PSUs granted during the six months ended June 30, 2024 was $10.64. As of June 30, 2024, there was $0.5 million of unrecognized compensation costs related to unvested time-based RSUs, which are expected to be recognized over a weighted-average period of 0.6 years, and $0.3 million of unrecognized compensation costs related to unvested PSUs, which are dependent upon achievement of the aforementioned clinical development milestones.

Stock-based compensation expense associated with stock options, RSUs, PSUs, and the Company’s ESPP included in the accompanying condensed consolidated statements of operations and comprehensive loss is as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	1,269	$	782	$	2,014	$	1,382
General and administrative		1,593		1,055		2,870		1,803
Total stock-based compensation expense	$	2,862	$	1,837	$	4,884	$	3,185