The Company’s 2021 Stock Option and Incentive Plan (the “2021 Plan”) was adopted by the Company’s board of directors and approved by the Company’s stockholders in June 2021 and became effective as of June 29, 2021. Upon the effectiveness of the 2021 Plan, the Company’s 2018 Equity Incentive Plan (the “2018 Plan”) was terminated and no further grants may be made thereunder. The Company’s 2021 Plan allows for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, stock bonuses, restricted stock, stock units and other forms of awards including cash awards to its officers, directors, employees, consultants and advisors.

A total of 2,600,000 shares of the Company’s common stock is authorized for issuance with respect to awards granted under the 2021 Plan. The share limit will automatically increase on the first trading day in January of each year (commencing with 2022) by an amount equal to the lesser of (1) 4% of the total number of outstanding shares of the Company’s common stock on the last trading day in December in the prior year, or (2) such lesser number as determined by the Company’s board of directors. Any shares subject to awards granted under the 2021 Plan or the 2018 Plan that are not paid, delivered or exercised before they expire or are canceled or terminated, or otherwise fail to vest, as well as shares used to pay the purchase or exercise price of such awards or related tax withholding obligations, will become available for new award grants under the 2021 Plan. As of June 30, 2021, 832,000 awards had been granted under the 2021 Plan, and 1,768,000 shares authorized under the 2021 Plan were available for award purposes.

The options that are granted under the 2021 Plan and the 2018 Plan are exercisable at various dates as determined upon grant and terminate within 10 years of the date of grant. The vesting period generally occurs over three to four years.

The following table summarizes the option activity under the 2021 Plan and 2018 Plan for the six months ended June 30, 2021:


				Weighted-
		Weighted-		Average
		Average		Remaining	Aggregate
		Exercise		Contractual Term	Intrinsic Value
	Options	Price		(in years)	(in thousands)
Outstanding at December 31, 2020	229,105	$	1.74	9.69	$	—
Granted	2,541,849		6.04	9.84
Exercised	—		—
Cancelled/Forfeited	—		—
Outstanding at June 30, 2021	2,770,954	$	5.69	9.79	$	47,439
Vested and exercisable at June 30, 2021	41,250	$	2.72	9.29	$	829
Vested and expected to vest at June 30, 2021	2,770,954	$	5.69	9.79	$	47,439

All exercisable options are vested and all outstanding options are vested or expected to vest.

The Company’s Employee Stock Purchase Plan (the “ESPP”) was adopted by the Company’s board of directors and stockholders in June 2021 and became effective upon the consummation of the IPO. A total of 230,000 shares of the Company’s common stock is initially available for issuance under the ESPP. The ESPP allows eligible employees to purchase shares of the Company’s common stock at a discount through payroll deductions of up to 15% of their eligible compensation, subject to any plan limitations. The ESPP provides for six-month offering periods, and at the end of each offering period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock on the first trading day of the offering period or on the last trading day of the offering period. As of June 30, 2021, no shares had been issued under the ESPP, and the full number of shares authorized under the ESPP Plan was available for issuance purposes upon the effectiveness of the ESPP.

The Company estimated the fair value of stock options using the Black-Scholes valuation model. The Company accounts for any forfeitures of options when they occur. Previously recognized compensation expense for an award is reversed in the period that the award is forfeited. The fair value of stock options was estimated using the following assumptions:


	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2021		2020		2021		2020
Expected term (in years)	5.8 - 6.1		6.0		5.8 - 6.1		6.0
Expected volatility	68.7 - 69.6	%	79.2 - 79.4	%	68.7 - 69.6	%	68.0 - 79.4	%
Risk-free interest rate	1.0 - 1.2	%	0.4	%	1.0 - 1.2	%	0.4 - 1.5	%
Expected dividend	—		—		—		—

Stock-based compensation expense recognized for stock option grants has been reported in the statements of operations and comprehensive loss as follows (in thousands):


	Three Months Ended				Six Months Ended
	June 30,				June 30,
		2021	2020			2021		2020
Research and development	$	101	$	2	$	113	$	2
General and administrative		220		4		231		11
Total	$	321	$	6	$	344	$	13

As of June 30, 2021, there was approximately $9.4 million of total unrecognized stock-based compensation expense related to nonvested stock-based compensation arrangements granted under the 2021 Plan and 2018 Plan, which is expected to be recognized over a weighted-average period of approximately 3.7 years.