Equity Incentive Plans and Stock-Based Compensation | . Equity Incentive Plans and Stock-Based Compensation As of March 31, 2022, there were 2,421,252 shares available for future issuance under the 2020 Equity Incentive Plan and 500,000 shares available for future issuance under the 2022 Inducement Equity Incentive Plan, which was adopted on March 1, 2022. The 2020 Equity Incentive Plan provides for the grants of stock options and other equity-based awards to employees, non-employee directors and consultants of the Company. The 2022 Inducement Equity Incentive Plan provides for the grants of equity-based awards to individuals not previously employees or non-employee directors of the Company. The table below summarizes the total stock-based compensation expense included in the Company’s statements of operations and comprehensive loss for the periods presented (in thousands): Three Months Ended 2022 2021 Research and development $ 1,568 $ 1,067 General and administrative 2,377 1,677 Total stock-based compensation expense $ 3,945 $ 2,744 Stock Options The following table summarizes the stock option activity for the three months ended March 31, 2022: Options Weighted- Weighted- Aggregate Outstanding at December 31, 2021 5,268,320 $ 14.16 Granted 1,333,234 9.48 Exercised ( 8,482 ) 1.88 Forfeited and cancelled ( 168,748 ) 17.87 Outstanding at March 31, 2022 6,424,324 $ 13.10 8.2 $ 5,487 Exercisable at March 31, 2022 2,812,462 $ 9.29 7.2 $ 5,037 The fair value of stock option awards to employees, executives, directors, and other service providers was estimated at the date of grant using the Black-Scholes-Merton option pricing model with the following assumptions: Three Months Ended 2022 2021 Risk-free interest rate 1.47 % - 1.70 % 0.6 % - 0.9 % Expected volatility 82.98 % - 83.59 % 88.38 % - 88.43 % Expected term (in years) 6.08 6.08 Expected dividend yield 0 % 0 % The Company recognized stock-based compensation expense related to the vesting of stock option s of $ 3.7 million and $ 2.7 million during the three months ended March 31, 2022 and 2021, respectively. The total unrecognized compensation expense related to outstanding unvested stock-option awards as of March 31, 2022, was $ 39.8 million, which is expected to be recognized over a weighted-average remaining service period of 2.9 years. Restricted Stock Units The following table summarizes the restricted stock unit activity for the three months ended March 31, 2022: Number of Shares Weighted- Outstanding at December 31, 2021 — $ — Granted 221,078 9.45 Vested — — Forfeited ( 3,348 ) 9.48 Outstanding at March 31, 2022 217,730 $ 9.45 The Company recognized stock-based compensation expense related to the vesting of restricted stock units of $ 0.1 million during the three months ended March 31, 2022. The Company did not grant restricted stock units in 2021. Total unrecognized compensation expense related to restricted stock units as of March 31, 2022, was $ 1.9 million, which is expected to be recognized over a weighted-average remaining service period of 2.7 years. Employee Stock Purchase Plan The company recognized stock-based compensation expense of $ 0.1 million related to the Employee Stock Purchase Plan (ESPP) for the three months ended March 31, 2022 . There was no ESPP expense for the three months ended March 31, 2021. Net Loss per Share The following outstanding shares of potentially dilutive securities were excluded from the computation of diluted net loss per share attributable to common stockholders for the periods presented because including them would have been anti-dilutive: Three Months Ended March 31, 2022 2021 Options to purchase common stock 6,424,324 5,067,230 Non-vested restricted stock units 217,730 — Total 6,642,054 5,067,230 |