9. Stock-based Compensation

On July 15, 2021, in connection with the completion of the Company’s IPO, the Company adopted a new comprehensive equity incentive plan, the 2021 Omnibus Equity Incentive Plan (the “2021 Plan”). Following the effective date of the 2021 Plan, no further awards may be issued under the 2018 Plan or the 2019 Plan (collectively, the “Prior Plans”). However, all awards under the Prior Plans that are outstanding as of the effective date of the 2021 Plan will continue to be governed by the terms, conditions and procedures set forth in the Prior Plans and any applicable award agreements. A total of 1,302,326 shares of common stock are reserved for issuance pursuant to the 2021 Plan. The 2021 Plan provides for the issuance of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock, restricted stock units, and other stock-based awards.

In October 2019, the Company adopted the 2019 Stock Option Plan (“2019 Plan”) which allowed for the granting of incentive stock options (“ISO”), non-qualified stock options (“NSO”) to the employees, members of the board of directors and consultants of the Company. In 2019 and during the first seven months of 2020, the Company granted ISOs and NSOs to consultants and directors from the 2019 Plan. As of December 31, 2019, 232,558 shares were authorized for issuance and 75,581 shares were available for future grant under the 2019 Plan. On April 6, 2020 the Company increased the shares authorized for issuance to 348,837 shares total. On February 17, 2021, the Company increased the shares authorized for issuance to 1,767,442 shares total. As of September 30, 2021, no further awards may be issued under the 2019 Plan.

In 2018, the Company adopted the 2018 Equity Incentive Plan (“2018 Plan”) which allowed for the granting of incentive stock options (“ISO”), non-qualified stock options (“NSO”), stock appreciation rights, restricted stock and restricted stock units to the employees, members of the board of directors and consultants of the Company. In 2018, the Company granted ISOs and NSOs to consultants and directors from this plan. As of December 31, 2020, 465,116 shares were authorized for issuance and 17,442 shares were available for future grant under the 2018 Plan. As of September 30, 2021, no further awards may be issued under the 2018 Plan.

During July 2021, in connection with the appointment of Dr. Brigitte Schiller to the Company’s board of directors, the Company granted Dr. Schiller 17,882 stock options with a ten year term, an exercise price of $5.00 per option, and a total fair value of $50,000 on the date of grant. Additionally, the Company granted Dr. Schiller 26,738 restricted stock units with a grant date fair value of $100,000. Subject to Dr. Schiller’s continued service, such options and restricted stock units shall vest upon the one-year anniversary of the date of grant. As of September 30, 2021, the unrecognized compensation cost related to outstanding restricted stock units was $0.1 million, which is expected to be recognized as expense over approximately 9 months.

The following table summarizes activity for stock options under all plans for the nine months ended September 30, 2021:

The grant date fair value of options granted during the nine months ended September 30, 2021 was $1.3 million.

As of September 30, 2021, the unrecognized compensation cost related to outstanding stock options was $1.5 million, which is expected to be recognized as expense over approximately 2.7 years.

The Company has recorded stock-based compensation expense, which includes expense related to restricted stock units, allocated by functional cost as follows for the three and nine months ended September 30, 2020 and 2021 (in thousands):

Fair Value of Stock Options

The assumptions are based on the following for each of the periods presented:

Expected Term - The expected term is calculated using the simplified method which is used when there is insufficient historical data about exercise patterns and post-vesting employment termination behavior. The simplified method is based on the vesting period and the contractual term for each grant, or for each vesting-tranche for awards with graded vesting. The mid-point between the vesting date and the maximum contractual expiration date is used as the expected term under this method.

Common Stock Fair Value - The fair value of the common stock underlying the Company’s stock options prior to the initial public offering was estimated at each grant date and was determined on a periodic basis and based either on transactions with third parties in which common stock was sold for cash or with the assistance of an independent third-party valuation expert. The assumptions underlying these valuations represented management’s best estimates, which involved inherent uncertainties and the application of significant levels of management judgment.

Volatility - The expected volatility being used is derived from the historical stock volatilities of a representative industry peer group of comparable publicly listed companies over a period approximately equal to the expected term of the options.

Risk-free Interest Rate - The risk-free interest rate is based on median U.S. Treasury zero coupon issues with remaining terms similar to the expected term on the options.

Expected Dividend - The Company has never declared nor paid any cash dividends and does not plan to pay cash dividends in the foreseeable future, and therefore, used an expected dividend yield of zero.

The following averaged assumptions were used to calculate the fair value of awards granted to employees, directors and non-employees for the nine months ended September 30, 2020 and 2021: