The Company adopted the 2020 Equity Incentive Plan (the 2020 Plan) in October 2020. The 2020 Plan is a successor to and continuation of the Amended and Restated 2016 Equity Incentive Plan (the 2016 Plan) and provides for the granting of stock options, stock appreciation rights, restricted stock, restricted stock units, and other stock or cash-based awards to individuals who are then employees, officers, directors or consultants. A total of 2,647,684 shares of common stock were approved to be initially reserved for issuance under the 2020 Plan, inclusive of the shares that remained available for issuance under the 2016 Plan at the time the 2020 Plan became effective. In addition, the number of shares of common stock available for issuance under the 2020 Plan will be automatically increased on the first day of each calendar year during the ten-year term of the 2020 Plan, beginning with January 1,

2021 and ending with January 1, 2030, by an amount equal to 5% of the outstanding number of shares of the Company’s common stock on December 31st of the preceding calendar year or such lesser amount as determined by the Company’s Board of Directors. No further grants will be made under the 2016 Plan; however, shares subject to awards granted under the 2016 Plan will continue to be governed by the 2016 Plan.

Under the 2020 Plan and the 2016 Plan, individuals can be granted the ability to early exercise their options. There were no shares, related to the early exercise of options, subject to repurchase by the Company as of June 30, 2022. As of June 30, 2022, a total of 4,985,297 shares were authorized for issuance under the 2020 Plan and 2,815,275 shares remained available for issuance, and a total of 1,275,158 shares were authorized for issuance under the 2016 Plan and no shares remained available for issuance.

A summary of the Company’s stock option activity and related information is as follows (in thousands, except share and per share amounts):


	Outstanding Stock Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (Years)		Aggregate Intrinsic Value
Balance as of December 31, 2021		2,215,942		$	4.72		6.9	$	3,959
Granted		2,143,125			3.23		—		—
Exercised		(992	)		1.39		—		—
Forfeited		(403,095	)		7.47		—		—
Balance as of June 30, 2022		3,954,980		$	3.63		8.1	$	410
Vested and expected to vest as of June 30, 2022		3,814,980		$	3.59		8.0	$	410
Vested and exercisable as of June 30, 2022		1,461,195		$	3.57		5.4	$	292

Stock options vested and expected to vest differs from total stock options outstanding as it excludes performance-based stock options for which the performance criteria have not been achieved and achievement is not expected as of June 30, 2022.

The aggregate intrinsic values of options outstanding and exercisable were calculated as the difference between the exercise price of the options and the estimated fair value of the Company’s common stock as of the respective balance sheet date. The total intrinsic value of options exercised was $1 thousand for the six months ended June 30, 2022. There were no options exercised during the three months ended June 30, 2022.

For the three and six months ended June 30, 2022, the weighted-average fair value of options granted was $1.47 per share and $2.56 per share, respectively.

A summary of the Company’s RSU activity and related information is as follows:


	RSUs
	Shares			Weight-Average Grant Date Fair Value Per Share
Unvested balance as of December 31, 2021		460,000		$	2.48
Granted		92,200			2.58
Vested		(64,347	)		2.49
Forfeited		(62,000	)		2.55
Unvested balance as of June 30, 2022		425,853		$	2.49

During the six months ended June 30, 2022, the Company granted 92,200 RSUs, including 68,775 RSUs subject to time-based vesting in installments through June 30, 2023, and 23,425 RSUs subject to performance-based vesting conditions related to the satisfaction of certain clinical development milestones.

The Board of Directors adopted and the Company’s stockholders approved the 2020 Employee Stock Purchase Plan (the ESPP) in October 2020. 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. At the end of each purchase period, employees are able to purchase shares at 85% of the lower of the fair market value of the Company’s common stock as of the offering date or the applicable purchase date. A total of 220,640 shares of common stock were approved to be initially reserved for issuance under the ESPP. In addition, the number of shares of common stock available for issuance under the ESPP will be automatically increased on the first day of each calendar year during the first ten-years of the term of the ESPP, beginning with January 1, 2021 and ending with January 1, 2030, by an amount equal to the lesser of (i) 1% of the outstanding number of shares of the Company’s common stock on December 31st of the preceding calendar year, (ii) 441,280 shares of common stock or (iii) such lesser amount as determined by the Board of Directors.

During the six months ended June 30, 2022, 25,545 shares were issued under the ESPP. As of June 30, 2022, 642,573 shares of common stock remained available for issuance under the ESPP.

The following table summarizes the components of stock-based compensation expense recognized in the Company’s condensed statements of operations and comprehensive loss during the three and six months ended June 30, 2022 and 2021 (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2022		2021		2022		2021
Research and development	$	245	$	346	$	545	$	610
General and administrative		660		664		1,501		1,520
Total stock-based compensation expense	$	905	$	1,010	$	2,046	$	2,130

As of June 30, 2022, there was approximately $7.4 million of unrecognized stock-based compensation expense related to stock options, which is expected to be recognized over a weighted-average vesting term of 2.9 years.

As of June 30, 2022, there was approximately $0.6 million of unrecognized stock-based compensation expense related to RSUs, which is expected to be recognized over an estimated weighted-average vesting term of 1.3 years.