On May 7, 2018, the Company established and adopted the 2018 Equity Incentive Plan (the “2018 Plan”) providing for the granting of stock awards for employees, directors and consultants to purchase shares of the Company’s common stock. Upon the effectiveness of the 2020 Plan (as defined below), the plan was terminated and no further issuances were made under the 2018 Plan, although it continues to govern the terms of any equity grants that remain outstanding under the 2018 Plan.

The 2020 Equity Incentive Plan (the “2020 Plan”) was approved by the Board of Directors and the Company’s stockholders and became effective on July 29, 2021. The Board of Directors, or committee thereof, is authorized to administer the 2020 Plan. The 2020 Plan provides for the grant of incentive stock options ("ISOs") within the meaning of Section 422 of the U.S. Internal Revenue Code of 1986, as amended, to employees, and for the grant of nonstatutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards, performance awards and other forms of awards to employees, directors and consultants and any affiliates’ employees and consultants. The number of shares initially reserved for issuance under the 2020 Plan was 4,200,000, which will automatically increase on January 1 of each year for a period of 10 years, beginning on January 1, 2022 and continuing through January 1, 2031, in an amount equal to 5% of the total number of shares of common stock outstanding on the last day of the immediately preceding year, or a lesser number of shares determined by the Board of Directors no later than the last day of the immediately preceding year. The maximum number of shares of common stock that may be issued upon the exercise of ISOs under the 2020 Plan will be 13,000,000 shares. As of December 31, 2021, 10,594,584 shares were available for grant pursuant to the Plan. On January 1, 2022, the shares reserved for issuance was increased to 5,139,062 shares.

The 2020 Employee Stock Purchase Plan (the “2020 ESPP”) was approved by the Company’s Board of Directors and the Company’s stockholders and became effective on July 29, 2021. A total of 200,000 shares of common stock were initially reserved for issuance under this plan, which will automatically increase on January 1 of each year for a period of 10 years, beginning on January 1, 2021 and continuing through January 1, 2031, by the lesser of 1% of the total number of shares of common stock outstanding on the last day of the immediately preceding year; and 400,000 shares, except before the date of any such increase, the Board of Directors may determine that such increase will be less than the amount set forth above. As of December 31, 2021, no shares of common stock had been issued under the 2020 ESPP and 200,000 shares remained available for future issuance under the 2020 ESPP. On January 1, 2022, the shares reserved for issuance was increased to 387,812 shares. The first offering period has not yet been decided by the Company’s Board of Directors or designated committee of the Company’s Board of Directors.

The following is a summary of the stock option award activity during the year ended December 31, 2021:


	Number of Stock Options			Weighted- Average Exercise Price			Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding at December 31, 2020		1,247,158		$	5.16			9.34	$	1,486
Granted		1,231,965			7.59
Exercised		(26,689	)		(1.09	)
Forfeited		(146,055	)		(5.76	)
Outstanding at December 31, 2021		2,306,379		$	6.51			8.99	$	983
Exercisable at December 31, 2021		503,206		$	6.00			8.37	$	544
Options expected to vest as of December 31, 2021		1,803,173		$	6.83			9.16	$	439

The weighted-average grant date fair value of options granted during the years ended December 31, 2021 and 2020 was $5.41 and $4.67, respectively. The aggregate intrinsic value is calculated as the difference between the exercise price and the market price of the Company’s common stock at the date of exercise. The aggregate intrinsic value of stock options exercised in the years ended December 31, 2021 and 2020 was $0.2 million and $0.1 million, respectively.

For the years ended December 31, 2021 and 2020, the Company utilized the Black-Scholes option-pricing model for estimating the fair value of the stock options. The following table presents the assumptions and the Company’s methodology for developing each of the assumptions used:


	December 31, 2021	December 31, 2020
Volatility	85.67%-89.15%	83.3%-90.9%
Expected life (years)	5.49-6.68	4.25-9.34
Risk-free interest rate	0.66%-1.32%	0.3%-1.4%
Dividend rate	—%	—%

Stock-based compensation expense was recorded in the following line items in the statements of operations for the years ended December 31, 2021 and 2020 (in thousands):


	Year Ended December 31,
	2021		2020
Research and development	$	1,014	$	192
General and administrative		1,181	$	165
Total stock-based compensation expense	$	2,195	$	357

No related tax benefits from stock-based compensation expense were recognized for the years ended December 31, 2021 and 2020. As of December 31, 2021, there was $8.3 million in unrecognized stock-based compensation expense, which is expected to be recognized over a weighted-average period of 3.11 years.