Stock Compensation

6 Months Ended

Jun. 30, 2024

Share-Based Payment Arrangement [Abstract]

8. STOCK COMPENSATION

In April 2021, the Company adopted the 2021 Employee Stock Purchase Plan (ESPP) and the 2021 Equity Incentive Plan (2021 EIP), each of which became effective in connection with the IPO. The Company has reserved 1,152,463 and 6,873,404 shares of Class A common stock for issuance under the ESPP and 2021 EIP, respectively.

The Company may not grant any additional awards under the 2017 Equity Incentive Plan (2017 EIP). The 2017 EIP will continue to govern outstanding equity awards granted thereunder. As of June 30, 2024, there were 663,680 shares available for issuance under the 2021 EIP.

2017 EIP and 2021 EIP

Stock option activity under the 2017 EIP and 2021 EIP was 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		1,973,100
Exercised		(1,067,162	)
Cancelled and forfeited		(419,602	)
Outstanding as of June 30, 2024		6,248,572		$	12.52		8.30	$	148,917
Options exercisable as of June 30, 2024		2,372,563		$	8.64		7.38	$	65,350
Vested and expected to vest as of June 30, 2024		6,248,572		$	12.52		8.30	$	148,917

The aggregate intrinsic value of stock options exercised during the three and six months ended June 30, 2024, was approximately $10.6 and $31.2 million, respectively. The weighted average grant date fair value of options granted during the three and six months ended June 30, 2024 was $28.97 and $13.46 per share, respectively.

ESPP

The ESPP enables eligible employees to purchase shares of the Company’s 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 the last day of the calendar month prior to the date of the increase, or such lower number of shares (including no shares) approved by the Company’s board of directors. As of June 30, 2024, 80,989 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. Stock-based compensation expense related to the ESPP for the three and six months ended June 30, 2024, was $0.1 million.

Stock-Based Compensation Expense

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 condensed statements of operations and comprehensive loss for the three and six months ended June 30, 2024 and 2023.


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Research and development	$	1,899	$	1,231	$	3,627	$	2,365
General and administrative		2,974		1,451		5,370		2,984
Total stock-based compensation expense	$	4,873	$	2,682	$	8,997	$	5,349


	Three Months Ended June 30,				Six Months Ended June 30,
	2024		2023		2024		2023
Employees	$	4,261	$	2,597	$	8,132	$	4,921
Nonemployees		612		85		865		428
Total stock-based compensation expense	$	4,873	$	2,682	$	8,997	$	5,349

As of June 30, 2024, the Company had $37.4 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 2.8 years.

The fair value of stock options granted during the three and six months ended June 30, 2024 and 2023, was estimated using the Black-Scholes option pricing model based on the following weighted-average assumptions.


	Three Months Ended June 30,		Six Months Ended June 30,
	2024	2023	2024	2023
Expected term (in years)	5.5 – 6.1	5.5 – 6.1	5.5 – 6.1	5.5 – 6.1
Expected volatility	71.9% – 72.8%	80.2% – 80.5%	67.7% – 72.8%	79.5% – 80.5%
Risk-free rate	4.3% – 4.6%	3.4% – 3.8%	3.8% – 4.6%	3.4% – 4.0%
Dividend yield	—	—	—	—

Restricted Stock Units

The Company grants restricted stock units (RSU) pursuant to the 2021 EIP and satisfies such grants through the issuance of its common stock. The following table shows RSU activity for the period ended June 30, 2024.


	Number of Shares			Weighted Average Grant Date Fair Value per Share
Unvested balance at December 31, 2023		131,679		$	18.36
Granted		389,362			18.67
Vested		(1,875	)		15.46
Cancelled and forfeited		(25,332	)		18.03
Unvested balance at June 30, 2024		493,834		$	18.63

For the six months ended June 30, 2024, the Company recognized $1.6 million of stock-based compensation for restricted stock units.

As of June 30, 2024, the Company had $6.8 million of unrecognized stock-based compensation expense related to unvested RSUs, which is expected to be recognized over a weighted-average period of approximately 2.9 years.

Inducement Plan

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 Marketplace 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. An aggregate of 500,000 shares of common stock were reserved for issuance under the Inducement Plan. As of June 30, 2024, there were 430,175 shares available for issuance under the Inducement Plan.