In August 2020, the Company’s board of directors and stockholders adopted the Company’s 2020 Equity Incentive Plan, or the 2020 Plan, that became effective in connection with the IPO, and serves as the successor to the Company’s 2015 Stock Incentive Plan, or the 2015 Plan. The Company’s 2020 Plan authorizes the award of stock options, restricted stock units, or RSUs, restricted stock awards, or RSAs, stock appreciation rights, or SARs, performance awards and stock bonus awards. The Company initially reserved 1,850,000 shares of its common stock, plus any reserved shares not issued or subject to outstanding grants under the 2015 Plan on the effective date of the 2020 Plan, for issuance pursuant to awards granted under the 2020 Plan. The aggregate number of shares reserved for sale under the 2020 Plan will increase automatically on each January 1st of 2021 through 2030 by the number of shares equal to the lesser of 5% of the aggregate number of outstanding shares of the Company’s common stock as of the immediately preceding December 31, or a number as may be determined by the Company’s board of directors.

In conjunction with adopting the 2020 Plan, the Company may not grant any additional stock-based awards under the 2015 Plan, and any shares available for issuance under the 2015 Plan were added to the shares reserved under the 2020 Plan. The 2015 Plan will continue to govern outstanding stock-based awards granted thereunder. As of December 31, 2020, there were 1,686,158 shares available for issuance under the 2020 Plan.

In August 2020, the Company’s board of directors and stockholders adopted the Company’s 2020 Employee Stock Purchase Plan, or the ESPP, that became effective in connection with the IPO, in order to enable eligible employees to purchase shares of the Company’s common stock with accumulated payroll deductions. The Company’s ESPP is intended to qualify under Section 423 of the Internal Revenue Code. The Company has initially reserved 210,000 shares of its common stock for sale under the ESPP. The aggregate number of shares reserved for sale under the Company’s ESPP will increase automatically on January 1st of each of the first ten calendar years after the first offering date under the ESPP by the number of shares equal to the lesser of 1% of the total outstanding shares of the Company’s common stock as of the immediately preceding December 31, or a number of shares as may be determined by the Company’s board of directors in any particular year. The aggregate number of shares issued over the term of the ESPP, subject to stock-splits, recapitalizations or similar events, may not exceed 2,100,000 shares of the Company’s common stock.

						Weighted
				Weighted		Average
				Average		Remaining		Aggregate
	Number of			Exercise		Contractual		Intrinsic
	Options			Price		Term		Value
						(In years)		(In thousands)
Outstanding—December 31, 2019		2,117,106		$	2.52		8.7	$	2,825
Granted		1,098,542		$	16.88
Exercised		(53,134	)	$	1.47
Forfeited and Canceled		(406,412	)	$	2.38
Outstanding—December 31, 2020		2,756,102		$	8.28		8.6	$	57,090
Options Exercisable—December 31, 2020		1,925,666		$	3.00		8.1	$	50,109

At December 31, 2019, the aggregate intrinsic value of options granted is calculated as the difference between the exercise price of the options and the estimated fair value of the Company’s common stock on the same date. At December 31, 2020, the aggregate intrinsic value of options granted is calculated as the difference between the exercise price and the closing price on the same date. The aggregate intrinsic value of options exercised in the years ended December 31, 2020 and 2019 was $113,000 and $157,000, respectively.

The aggregate fair value of options that vested during the years ended December 31, 2020 and 2019 was $1.4 million and $659,000, respectively. The weighted-average grant-date fair value per share of options that vested during the years ended December 31, 2020 and 2019 was $2.43 and $1.44, respectively.

During the year ended December 31, 2020, the Company issued 80,000 RSUs under the 2020 Plan. The weighted-average grant-date fair value per share of the RSUs was $16.50. As of December 31, 2020, none of the RSUs had vested or forfeited.

The Company estimates the fair value of stock option awards on the grant date using Black-Scholes. The weighted-average grant date fair value per option granted during the years ended December 31, 2020 and 2019 was $11.90 and $2.16, respectively. The fair value of each award is estimated using Black-Scholes based on the following assumptions:

	Year Ended December 31,
	2020		2019
Expected term (years)	5.0-6.1		5.1-6.1
Expected volatility	85%		80%
Risk-free interest rate	0.25%-0.53%		1.8%-2.5%
Expected dividend		—		—

Black-Scholes requires the use of subjective assumptions which determine the fair value of stock-based awards. These assumptions include:

Expected Term: The expected term represents the period that options are expected to be outstanding and is determined using the simplified method, based on the mid-point between the vesting date and the end of the contractual term.

Expected Volatility: The expected volatility is estimated based on the average volatility for comparable publicly-traded biopharmaceutical companies over a period equal to the expected term of the stock option grants as the Company does not yet have sufficient historical trading history for its own stock. The comparable companies are chosen based on their similarities to the Company, including life cycle stage, therapeutic focus and size. The Company will continue to apply this method until a sufficient amount of historical information over a period equal to the expected term of the stock-based awards becomes available.

Risk-free Interest Rate. The risk-free interest rate is based on the U.S. Treasury zero coupon issues in effect at the time of grant for periods corresponding with the expected term of the stock option grants.

Expected Dividend: The Company has never paid dividends on its common stock and has no plans to pay dividends on its common stock. Therefore, the Company used an expected dividend yield of zero.

	Year Ended December 31,
	2020		2019
Research and development	$	390	$	215
General and administrative		1,398		523
Total stock-based compensation expense	$	1,788	$	738

As of December 31, 2020, the total unrecognized stock-based compensation expense related to outstanding unvested stock awards that are expected to vest was $15.0 million, which the Company expects to recognize over an estimated weighted-average term of 3.5 years.

During the year ended December 31, 2019, the Company accelerated the vesting of 61,812 unvested stock options and extended the exercise period related to the awards. The modification resulted in additional stock-based compensation of $128,000.