In February 2024, the Company adopted the 2024 Inducement Plan (Inducement Plan). The Inducement Plan was adopted by the compensation committee of the Company’s board of directors without stockholder approval pursuant to Nasdaq Listing Rule 5635(c)(4). In accordance with Rule 5635(c)(4), awards made under the Inducement Plan, including stock options and restricted stock units, may only be granted to newly hired employees as a material inducement to accept employment with the Company. Awards granted under the Inducement Plan expire no later than ten years from the date of grant.

The 2021 Equity Incentive Plan (2021 EIP) and the 2017 Equity Incentive Plan (2017 EIP) became effective in May 2021 and February 2017, respectively. Awards granted under the 2021 EIP and 2017 EIP expire no later than 10 years from the date of grant.

The 2017 EIP permitted the granting of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards to employees, directors and consultants. Since the adoption of the 2021 EIP, no additional equity awards can be granted under the 2017 EIP. Shares reserved and remaining available for issuance under the 2017 EIP were added to shares reserved for the 2021 EIP plan in May 2021. The terms of the 2017 EIP continue to govern outstanding equity awards granted thereunder.

Under the 2021 EIP, we may grant incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards and restricted stock units, performance awards and other awards to employees, consultants and directors. Stock options granted to new employees generally vest over four years at a rate of 25% upon the first anniversary of the vesting commencement date and monthly thereafter. Other stock options granted to employees generally vest monthly over four years from the vesting commencement date. The number of shares reserved for issuance under the 2021 EIP increases automatically on the first day of each fiscal year, beginning on January 1, 2022, by a number equal to 5% of the total number of shares of the Company’s capital stock (including all classes of the Company’s common stock) outstanding on December 31 of the preceding year, or such lower number of shares (including no shares) approved by the Company’s board of directors prior to January 1 of a given year.

The 2021 Employee Stock Purchase Plan (ESPP) became effective in May 2021. The ESPP enables eligible employees to purchase shares of the Company’s Class A common stock at the end of each offering period at a price equal to 85% of the fair market value of the shares on the first trading day or the last trading day of the offering period, whichever is lower. Eligible employees generally include all employees. Share purchases are funded through payroll deductions of at least 1% and up to 15% of an employee’s eligible compensation for each payroll period. The number of shares reserved for issuance under the ESPP increases automatically on the first day of each fiscal year, beginning on January 1, 2022, by a number equal to the lesser of 440,502 shares, 1% of the total number of shares of the Company’s capital stock (including all classes of the Company’s common stock) outstanding on December 31 of the preceding year, or such lower number of shares (including no shares) approved by the Company’s board of directors prior to January 1 of a given year. As of December 31, 2024, 88,752 shares have been issued pursuant to the ESPP. The ESPP generally provides for six-month consecutive offering periods beginning on September 14, 2021. The ESPP is a compensatory plan as defined by the authoritative guidance for stock compensation.

The table below summarizes the Company's equity plans as of December 31, 2024:


Plan	Maximum Number of Shares Authorized		Shares Available for Future Issuance
2024 Inducement Plan		1,250,000		71,075
2021 Equity Incentive Plan		6,873,404		682,278
2017 Equity Incentive Plan		2,275,305		—
2021 Employee Stock Purchase Plan		1,148,444		1,059,692

Stock option activity under the 2017 EIP, 2021 EIP, and 2024 Inducement Plan is summarized as follows:


	Number of Options			Weighted-Average Exercise Price per Share		Weighted-Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value (000s)
Outstanding as of December 31, 2023		5,762,236		$	9.42		7.66	$	39,197
Granted		2,799,750		$	25.83
Exercised		(1,486,314	)	$	8.66
Cancelled and forfeited		(463,875	)	$	10.93
Outstanding as of December 31, 2024		6,611,797		$	16.44		8.11	$	172,630
Options exercisable as of December 31, 2024		2,703,670		$	9.65		7.11	$	88,257
Vested and expected to vest as of December 31, 2024		6,611,797		$	16.44		8.11	$	172,630

The aggregate intrinsic value of stock options exercised during the year ended December 31, 2024 was $46.8 million. The weighted-average grant date fair value of options granted during the years ended December 31, 2024 and 2023, was $19.65 per share and $5.92 per share, respectively.

In August 2024, the Company repurchased 4,450 unvested shares that were previously outstanding due to a stock option that was early exercised. The unvested shares were repurchased at the original exercise price of $2.8968 per share.

The Company grants restricted stock units (RSU) pursuant to the 2021 EIP and satisfies such grants through the issuance of the Company’s Class A common stock. The following table shows RSU activity for the period ending December 31, 2024:


	Number of Shares			Weighted-Average Grant Date Fair Value per Share
Unvested balance at December 31, 2023		131,679		$	18.36
Granted		713,812			29.67
Vested		(111,396	)		19.03
Cancelled and forfeited		(37,207	)		22.33
Unvested balance at December 31, 2024		696,888		$	29.63

The following tables summarize the stock-based compensation expense for stock options and restricted stock units granted to employees and nonemployees and for ESPP stock-based compensation that was recorded in the Company’s statements of operations and comprehensive loss for the years ended December 31, 2024 and 2023 (in thousands):


	Year Ended December 31,
	2024		2023
Research and development	$	8,537	$	4,845
General and administrative		12,265		6,648
Total stock-based compensation expense	$	20,802	$	11,493


	Year Ended December 31,
	2024		2023
Employees	$	18,356	$	10,494
Nonemployees		2,446		999
Total stock-based compensation expense	$	20,802	$	11,493

As of December 31, 2024, the Company had $49.3 million of unrecognized stock-based compensation expense related to unvested stock options, which is expected to be recognized over a weighted-average period of approximately 2.7 years. For the year ended December 31, 2024, the Company recognized $17.1 million of stock-based compensation expense for stock options.

As of December 31, 2024, the Company had $18.6 million of unrecognized stock-based compensation expense related to unvested RSUs, which is expected to be recognized over a weighted-average period of approximately 3.5 years. For the year ended December 31, 2024, the Company recognized $3.4 million of stock-based compensation expense for restricted stock units.

Stock-based compensation expense related to the ESPP for the years ended December 31, 2024 and 2023 was $0.3 million and $0.2 million, respectively.

No tax benefit was recognized related to stock-based compensation expense since the Company has never reported taxable income and has established a full valuation allowance to offset all of the potential tax benefits associated with its deferred tax assets.

The fair value of stock options granted during the years ended December 31, 2024 and 2023, was estimated using the Black-Scholes option pricing model based on the following assumptions:


	Year Ended December 31,
	2024	2023
Expected term (in years)	5.4 – 6.1	5.5 – 6.1
Expected volatility	69.7% – 73.2%	79.5% – 80.5%
Risk-free rate	3.6% – 4.6%	3.4% – 4.7%
Dividend yield	—	—