The Company’s 2016 Stock Incentive Plan, (the “2016 Plan”) provided for the grant of restricted stock, restricted stock units, stock appreciation rights, incentive stock options, non-statutory stock options and other stock-based awards to employees, officers, members of the Board, consultants and advisors of the Company.

As of the effective date of the 2020 Equity Incentive Plan, no shares remained available for future issuance under the 2016 Plan. Any options or awards outstanding under the 2016 Plan remained outstanding and effective.

On October 1, 2019, the Company’s board of directors adopted, and on February 26, 2020 the Company’s stockholders approved, the 2020 Equity Incentive Plan (the “2020 Plan”), which became effective on March 11, 2020. The 2020 Plan provides for the grant of incentive stock options, non-qualified stock options, stock appreciation rights, restricted stock awards, restricted stock units and other stock-based awards. The number of shares reserved for issuance under the 2020 Plan is the sum of: (1) 1,220,283 shares of the Company’s common stock; plus (2) the number of shares (up to a maximum of 2,091,969 shares) equal to the sum of (x) 228,852 shares, which represents the Company’s common stock reserved for issuance under the 2016 Plan that remained available for grant under the 2016 Plan as of March 11, 2020 and (y) the number of shares of the Company’s common stock subject to outstanding awards granted under the 2016 Plan that expire, terminate or are otherwise surrendered, cancelled, forfeited or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right. The number of shares reserved shall be annually increased on the first day of each fiscal year, beginning with the fiscal year ending December 31, 2021 and continuing until, and including, the fiscal year ending December 31, 2030, equal to the lesser of (i) 4% of the number of shares of the Company’s common stock outstanding on the first day of such fiscal year and (ii) an amount determined by the Company’s board of directors. On January 1, 2021, 701,930 additional shares were reserved for issuance under the 2020 Plan pursuant to this provision. On January 1, 2022, a further

1,051,490 shares were reserved for future under the 2020 Plan pursuant to this provision. No more than 8,541,982 shares of common stock may be issued as incentive stock options under the 2020 Plan. The shares of common stock underlying any awards that expire, terminate, or are otherwise surrendered, cancelled, forfeited or repurchased by the Company under the 2016 Plan or the 2020 Plan will be added back to the shares of common stock available for issuance under the 2020 Plan.

As of December 31, 2021, there were 1,216,532 shares available for future issuance under the 2020 Plan.

For financial reporting purposes, prior to the IPO the Company performed common stock valuations with the assistance of a third-party specialist to determine stock-based compensation expense for stock options. Upon completion of the IPO, the fair value of the common stock on the grant date was based on the closing price of the stock on the Nasdaq Global Select Market on the date of grant.

	Number of Shares			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Term (in years)		Aggregate Intrinsic Value (in thousands)
Outstanding as of December 31, 2020		1,935,632		$	9.85		8.14
Granted		952,953			10.19
Exercised		(158,681	)		4.34
Forfeited		(356,880	)		14.69
Outstanding as of December 31, 2021		2,373,024		$	9.63	8.19		$	—
Options vested and exercisable as of December 31, 2021		880,958		$	7.07	7.33		$	—

The aggregate intrinsic value of options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the common stock as of the end of the period.

The weighted-average grant date fair value of the Company’s stock options granted during the years ended December 31, 2021 and 2020 was $7.00 and $12.95, respectively.

The assumptions that the Company used to determine the grant date fair value of stock options granted to employees, non-employees and members of the Board during the years ended December 31, 2021 and 2020 were as follows, presented on a weighted-average basis:

	Year Ended December 31,
	2021			2020
Expected term (in years)		6.20			6.17
Expected volatility		81.0	%		74.7	%
Expected dividend yield		0.00	%		0.00	%
Risk-free interest rate		0.81	%		0.52	%

The Company granted stock options to purchase an aggregate of 220,928 shares of common stock to certain employees, officers and consultants and advisors of the Company on May 16, 2019, June 5, 2019 and June 21, 2019, which contain performance-based vesting criteria. Vesting of these options was contingent on the closing of the second tranche of Series B Preferred Stock financing. Stock-based compensation expense associated with performance-based stock options is recognized if the performance conditions are considered probable of being achieved, using management’s best estimates. As a result of the performance condition being met on February 25, 2020, these options vested as to 25% of the shares underlying each option on February 25, 2021 and vest as to the remainder of the shares in equal quarterly installments for three years thereafter. The Company recognized stock-based compensation expense of $0.2 million and $0.3 million for these options during the years ended December 31, 2021 and December 31, 2020, respectively.

Stock-based compensation expense included in the Company’s consolidated statements of operations and comprehensive loss is as follows (in thousands):

	Year Ended December 31,
	2021		2020
General and administrative	$	2,441	$	1,490
Research and development		1,404		741
Total stock-based compensation expense	$	3,845	$	2,231

As of December 31, 2021, total unrecognized compensation cost related to the unvested stock-based awards was $9.4 million, to be recognized over a weighted-average period of 2.65 years.

On October 1, 2019, the Company’s board of directors adopted, and on February 26, 2020, the Company’s stockholders approved the 2020 Employee Stock Purchase Plan (the “2020 ESPP”), which became effective on March 11, 2020. The 2020 ESPP permits eligible employees who elect to participate, in six-month offering periods, to purchase shares of common stock through payroll deductions at a price equal to 85% of the fair market value of the common stock on the first or last business day of each applicable six-month offering period, whichever is lower. Purchase dates under the ESPP occur on or about June 14 and December 14 each year.

The 2020 ESPP initially provides participating employees with the opportunity to purchase up to an aggregate of 193,216 shares of the Company’s common stock. The number of shares of the Company’s common stock reserved for issuance under the 2020 ESPP will automatically increase on the first day of each fiscal year, beginning with the fiscal year commencing on January 1, 2021 and continuing until, and including, the fiscal year commencing on January 1, 2031, in an amount equal to the lowest of (i) 386,432 shares of the Company’s common stock, (ii) 1% of the number of shares of the Company’s common stock outstanding on the first day of such fiscal year and (iii) an amount determined by the Company’s board of directors. The Company’s board of directors decided not to increase the number of shares of the Company’s common stock reserved for issuance under the 2020 ESPP for the 2021 fiscal year. On January 1, 2022, 262,872 additional shares were reserved for issuance under the 2020 ESPP pursuant to this provision.

During the year ended December 31, 2021, less than $0.1 million was withheld from employees, on an after-tax basis, in order to purchase 15,696 shares of the Company’s common stock. The Company recorded stock-based compensation expense related to the 2020 ESPP of less than $0.1 million. As of December 31, 2021, 175,667 shares of the Company’s common stock remained available for issuance under the 2020 ESPP.

As of December 31, 2021, there was less than $0.1 million of total unrecognized stock-based compensation expense related to the ESPP. The expense is expected to be recognized over a period of 5.5 months.