Stock-Based Compensation | Stock-Based Compensation During January 2017, the Company adopted the 2017 Equity Incentive Plan (“2017 Plan”), which provides for the granting of restricted stock, options to purchase shares of common stock and other awards to employees, directors and consultants. In March 2017, the Company amended the 2017 Plan to increase the number of available shares to 660,838. In September 2018, the Company adopted the 2018 Equity Incentive Plan (“2018 Plan”) which provides for granting of restricted stock, options to purchase shares of common stock, and other awards to employees, directors and consultants, and reserved 1,741,770 shares for this purpose. The 2018 Plan was amended in July 2018 to increase the number of available shares to 1,809,143. In February 2021, the Company adopted the 2021 Equity Incentive Plan (“2021 Plan”) and have reserved a total of 5,202,624 shares under the plan. No further shares will be issued under the 2017 and 2018 plans. There are 1,863,566 shares available for issuance under the 2021 plan as of March 31, 2023. The number of options to be granted under the 2021 Plan, the option exercise prices, and other terms of the options are determined by the Board of Directors in accordance with the terms of the 2021 Plan. Generally, stock options are granted at fair value, become exercisable over a period of one Stock-based compensation expense was recorded in the following financial statement line items within the statement of operations for the periods ended March 31, 2023 and 2022: Three Months Ended March 31, 2023 2022 Research and development expenses $ 259,730 $ 1,132,762 General and administrative expenses 582,716 513,090 Total stock-based compensation expense $ 842,446 $ 1,645,852 The following is a summary of option activity under the Company’s Stock Option Plans: Stock Options Weighted Weighted Aggregate Outstanding as of January 1, 2023 3,965,502 $ 7.38 8.0 $ — Granted — — Exercised — — Cancelled (841) 10.50 Forfeited (194,933) 5.95 Outstanding as of March 31, 2023 3,769,728 $ 7.45 6.3 — Vested or expected to vest as of March 31, 2023 3,769,728 $ 7.45 6.3 — Exercisable as of March 31, 2023 2,082,403 $ 9.09 4.3 — Shares unvested as of March 31, 2023 1,687,325 $ 5.42 8.9 $ — There were no option grants in the three months ended March 31, 2023. The weighted average fair value of the options granted during the three months ended March 31, 2022 was $1.99. The options were valued using the Black-Scholes option-pricing model for the three months ended March 31, 2022 with the following assumptions: 2022 Expected volatility 78.8% to 79.0% Risk-free interest rate 1.5% to 1.7% Expected dividend yield 0 % Expected term 6.1 years No options were exercised in three months ended March 31, 2023. The intrinsic value of stock options exercised for the three months ended March 31, 2022 was immaterial. As of March 31, 2023, there was $5.2 million of total unrecognized compensation expense related to unvested options that will be recognized over a weighted average period of 2.1 years. Restricted Stock Units A restricted stock unit (“RSU”) represents the right to receive one of the Company’s common stock upon vesting of the RSU. The fair value of each RSU is based on the closing price of the Company’s common stock on the date of grant. The following is a summary of RSU activity for the 2021 Plan for the three months ended March 31, 2023: Number of restricted units Weighted average grant date fair value Unvested and outstanding at January 1, 2023 1,558,000 $ 0.45 Granted — — Vested — — Forfeited (22,400) 0.45 Unvested and outstanding as of March 31, 2023 1,535,600 $ 0.45 As of March 31, 2023, there was $0.5 million of unrecognized compensation expense related to unvested RSUs, which are expected to be recognized over a weighted average period of 1.1 years. |