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Stockholders' Equity (Tables) | 9 Months Ended
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Sep. 30, 2023
Equity [Abstract] |
Schedule of Stock-Based Compensation Expense | Stock-based compensation expense for the three and nine months ended September 30, 2023 and 2022 has been reported in the condensed statements of operations and comprehensive loss as follows (in thousands):
|  | Three Months Ended September 30, |  |  | Nine Months Ended September 30, |
|  | 2023 |  |  | 2022 |  |  | 2023 |  |  | 2022 |
Research and development |  | $ | 1,321 |  |  | $ | 1,427 |  |  | $ | 4,322 |  |  | $ | 4,125 |
General and administrative |  |  | 2,196 |  |  |  | 2,161 |  |  |  | 6,484 |  |  |  | 6,937 |
Total |  | $ | 3,517 |  |  | $ | 3,588 |  |  | $ | 10,806 |  |  | $ | 11,062 |
Summary of Restricted Stock Units | The following table summarizes RSU activity under the 2020 Plan for the nine months ended September 30, 2023:
|  | Number of Shares |  |  | Weighted - Average Grant Date Fair Value |
Outstanding at December 31, 2022 |  |  | 510,039 |  |  | $ | 18.00 |
Granted |  |  | 34,468 |  |  | $ | 2.32 |
Vested |  |  | (361,412 | ) |  | $ | 16.50 |
Forfeited |  |  | (21,876 | ) |  | $ | 18.00 |
Outstanding at September 30, 2023 |  |  | 161,219 |  |  | $ | 18.00 |
Summary of Stock Option Activity | The following table summarizes stock option activity under the 2020 Plan for the nine months ended September 30, 2023:
|  | Number of Options |  |  | Weighted - Average Exercise Price Per Share |  |  | Weighted -Average Remaining Contractual Term (In Years) |  |  | Aggregate Intrinsic Value |
Balance at December 31, 2022 |  |  | 2,736,918 |  |  | $ | 13.82 |  |  |  | 8.82 |  |  | $ | 3,636,148 |
Granted |  |  | 4,006,395 |  |  | $ | 3.75 |  |  |  |  |  |  |
Exercised |  |  | — |  |  | $ | — |  |  |  |  |  |  |
Forfeited |  |  | (364,018 | ) |  | $ | 7.22 |  |  |  |  |  |  |
Expired |  |  | (16,909 | ) |  | $ | 22.44 |  |  |  |  |  |  |
Balance at September 30, 2023 |  |  | 6,362,386 |  |  | $ | 7.83 |  |  |  | 8.76 |  |  |  |
Vested and expected to vest at September 30, 2023 |  |  | 6,362,386 |  |  | $ | 7.83 |  |  |  | 8.76 |  |  | $ | — |
Exercisable at September 30, 2023 |  |  | 1,364,478 |  |  | $ | 15.60 |  |  | 7.45 |  |  | $ | — |
Summary of Assumptions Used in Black-Scholes Model | The assumptions used in the Black-Scholes option pricing model to determine the fair value of stock option grants were as follows:
|  | Nine Months Ended September 30,
|  | 2023 |  | 2022
Expected volatility |  | 77.9% |  | 74.8%
Risk-free interest rate |  | 3.88% |  | 2.05%
Expected dividend yield |  | 0.0% |  | 0.0%
Expected term |  | 6.05 years |  | 6.04 years
Schedule of Common Stock Reserved for Future Issuance | Common stock reserved for future issuance are as follows in common equivalent shares:
|  | September 30, 2023 |  |  | December 31, 2022 |
Common stock options and restricted stock units issued and outstanding |  |  | 6,523,605 |  |  |  | 3,246,957 |
Awards available for future issuance under the 2020 Plan |  |  | 912,955 |  |  |  | 3,012,554 |
Awards available for future issuance under the ESPP |  |  | 1,521,559 |  |  |  | 1,070,402 |
Total common stock reserved for future issuance |  |  | 8,958,119 |  |  |  | 7,329,913 |

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