Stock-Based Compensation | 8. Stock-Based Compensation In 2014, the Company’s Board of Directors and stockholders approved and adopted the 2014 Stock Plan (the “2014 Plan”). The 2014 Plan permitted the grant of options and restricted stock awards (including restricted stock purchase rights and restricted stock bonus awards). The 2014 Plan was terminated on the date the 2020 Equity Incentive Plan (the “2020 Plan”), which is described below, became effective, and no additional awards will be made pursuant to the 2014 Plan. However, any outstanding awards granted under the 2014 Plan will remain outstanding, subject to the terms of the 2014 Plan award agreements, until such outstanding options are exercised or until any awards terminate or expire by their terms. In 2020, the Company’s Board of Directors and stockholders approved and adopted the 2020 Equity Incentive Plan (the “2020 Plan”). The 2020 Plan permits the grant of options, restricted stock awards, stock appreciation rights, restricted stock unit awards, performance awards, and other awards. The maximum number of shares of common stock that may be issued under the 2020 Plan will not exceed 6,494,510 shares of the Company’s common stock, which is the sum of (i) 2,152,080 new shares, plus (ii) an additional number of shares not to exceed 4,342,430 shares, consisting of any shares of the Company’s common stock subject to outstanding stock options or other stock awards granted under the Company’s 2014 Plan that, on or after the 2020 Plan becomes effective, terminate or expire prior to exercise or settlement; are not issued because the award is settled in cash; are forfeited because of the failure to vest; or are reacquired or withheld (or not issued) to satisfy a tax withholding obligation or the purchase or exercise price. In addition, the number of shares of the Company’s common stock reserved for issuance under the 2020 Plan automatically increases on January 1 of each year for a period of ten years, beginning on January 1, 2021 and continuing through January 1, 2030, in an amount equal to the lesser of (1) 5% of the total number of shares of the Company’s common stock outstanding on December 31 of the immediately preceding year, or (2) a lesser number of shares determined by the Company’s board of directors no later than December 31 of the immediately preceding year. In 2022, the Company’s Board of Directors approved and adopted the 2022 Inducement Plan (the “2022 Inducement Plan”). Under the 2022 Inducement Plan, initially 2,000,000 shares of common stock were reserved for issuance. The 2022 Inducement Plan permits the grant of options, restricted stock awards, stock appreciation rights, restricted stock unit awards, performance awards, and other awards. The exercise price for each option and stock appreciation right shall be established at the discretion of the Board, provided that the exercise price of a stock option will not be less than 100% of the fair market value of the Company’s common stock on the date of grant. Specific vesting for stock options and stock appreciation rights is service related and determined in each award agreement, where stock options and stock appreciation rights are fully vested at the grant date or follow a graded vesting schedule. Stock options and stock appreciation rights granted under the Plan generally expire ten years after the date of grant. Stock Option Valuation The fair value of stock option grants is estimated using the Black-Scholes option-pricing model. The Company lacks company-specific historical and implied volatility information. Therefore, it estimated its expected stock volatility based on the historical volatility of a publicly traded set of peer companies in addition to its own historical volatility. For options with service- based vesting conditions, the expected term of the Company’s stock options has been determined utilizing the “simplified” method for awards that qualify as “plain-vanilla” options. The expected term of stock options granted to nonemployees is equal to the contractual term of the option award. The risk-free interest rate is determined by reference to the U.S. Treasury yield curve in effect at the time of grant of the award for time periods approximately equal to the expected term of the award. Expected dividend yield is 0% since the Company has never paid cash dividends and does not expect to pay any cash dividends in the foreseeable future. The assumptions that the Company used to determine the estimated grant-date fair value of stock options granted to employees and directors under the 2020 Plan and the 2022 Inducement Plan were as follows, presented as a weighted average: December 31, December 31, 2022 2021 Risk-free interest rate 1.99% 0.95% Expected term (in years) 6.03 5.97 Expected volatility 79.71% 77.55% Expected dividend yield — — Stock Option Activity The following table summarizes the stock option activity under the 2014 Plan, the 2020 Plan and the 2022 Inducement Plan: Weighted Weighted Average Average Remaining Number of Exercise Contractual Aggregate Shares Price Term Intrinsic Value (in years) (in thousands) Outstanding as of December 31, 2021 5,768,028 $ 15.99 8.82 $ 11,365 Granted 3,293,640 5.53 — — Exercised(1) (115,448) 3.06 — — Forfeited (561,362) 23.64 — — Outstanding as of December 31, 2022(2) 8,384,858 $ 8.59 8.30 $ 262 Options vested and exercisable as of December 31, 2022 3,270,694 $ 10.21 7.79 $ 215 Options expected to vest as of December 31, 2022 5,114,164 $ 7.56 8.63 $ 47 (1) Exercised amount includes vesting of early exercised options. (2) Balance as of December 31, 2022 includes 18,640 unvested early exercised stock options. The weighted-average grant-date fair value per share of options granted during the years ended December 31, 2022 and 2021 was $3.83 and $21.87, respectively. For the years ended December 31, 2022 and 2021, there were 1,670,701 and 1,286,729 shares vested, respectively. The weighted-average grant date fair value per share of options vested during the years ended December 31, 2022 and 2021 was $6.76 and $7.48, respectively. The total fair value of options vested during the years ended December 31, 2022 and 2021 was $11.3 million and $10.9 million, respectively. The aggregate intrinsic value of options exercised during the years ended December 31, 2022 and 2021 was $0.3 million and $0.7 million, respectively. As of December 31, 2022, the total unrecognized compensation expense related to unvested options was $34.7 million, which the Company expects to recognize over an estimated weighted average period of 2.54 years. Early Exercise of Stock Options In September 2020, one employee and one non-employee paid $0.6 million to early exercise 135,525 options with exercise prices ranging from $4.406 per share to $4.824 per share. As of December 31, 2022, 116,885 of such shares had vested with the remaining shares vesting over their respective terms. The terms of the 2014 Plan permit certain option holders to exercise options before their options are vested, subject to certain limitations. The early exercised options are subject to the same vesting provisions in the original stock option awards. Shares issued as a result of early exercise that have not vested are subject to repurchase by the Company upon termination of the purchaser’s employment, at the price paid by the purchaser. Such shares are not deemed to be outstanding for accounting purposes until they vest and are therefore excluded from shares outstanding and from basic and diluted net loss per share until the repurchase right lapses and the shares are no longer subject to the repurchase feature. A liability is recognized related to the cash proceeds of the unvested options and is reclassified into common stock and additional paid-in capital as the shares vest and the repurchase right lapses. Accordingly, the Company has recorded the unvested portion of the exercise proceeds of $0.1 million in other current liabilities as of December 31, 2022. Restricted Stock Awards In June 2020, the Company granted to certain employees 789,095 shares of restricted common stock (the “RSAs”) under the 2014 Plan as consideration for services with a deemed value of $2.40 per share, or $1.9 million. The following table summarizes the restricted stock activity under the Plan during the year ended December 31, 2022: Number of Shares Grant Date Fair Value Unvested restricted stock as of December 31, 2021 493,185 $ 2.40 Granted — Vested (197,274) 2.40 Forfeited — Unvested restricted stock as of December 31, 2022 295,911 $ 2.40 The total grant date fair value of the RSAs vested during the year ended December 31, 2022, was $0.5 million . Performance-Based Restricted Stock Unit Awards In November 2022, the Company granted to certain employees 710,000 shares of performance-based restricted stock unit awards (the “PSUs”) under the 2020 Plan as consideration for services subject to performance conditions with a fair value based on the closing price of the underlying common stock on the date of grant. Pursuant to the terms of the PSUs, 65% of each PSU vests upon certification by the Compensation Committee of the Company of achieving a pre-determined performance goal by June 30, 2024, and 35% of each PSU vests upon certification by the Compensation Committee of the Company of achieving a pre-determined performance goal by June 30, 2024. Expense recognition for PSUs commences when it is determined that attainment of the performance goal is probable or met. As of December 31, 2022, it was determined that the performance goals were not yet met, and therefore, the Company recorded zero stock-based compensation expense related to the PSUs for the year ended December 31, 2022. 2020 Employee Stock Purchase Plan (“2020 ESPP”) In 2020, the Company’s board of directors and stockholders approved and adopted the 2020 ESPP. The 2020 ESPP permits eligible employees who elect to participate in an offering under the 2020 ESPP to have up to 15% of their eligible earnings withheld, subject to certain limitations, to purchase shares of common stock pursuant to the 2020 ESPP. The price of the common stock purchased under the 2020 ESPP is equal to the lesser of (i) 85% of the fair market value of a share of the Company’s common stock on the first day of an offering; or (ii) 85% of the fair market value of a share of the Company’s common stock on the date of purchase. Each offering period is not to exceed 27 months and will include one or more purchase periods (each a “Purchase Period”) as approved by the Company’s board of directors in the offering. The current offering period will consist of two (2) six-month purchase periods (each a “Purchase Period”) during which payroll deductions of the participants are accumulated under the 2020 ESPP. The last business day of each Purchase Period is referred to as the “Purchase Date.” A total of 430,416 shares of common stock were initially reserved for issuance pursuant to the 2020 ESPP. The 2020 ESPP is a compensatory plan as defined by the authoritative guidance for stock-based compensation. The Company uses the Black-Scholes option-pricing model to estimate the fair value of stock offered under the 2020 ESPP. Stock-based compensation expense related to the 2020 ESPP was $0.4 million and $0.2 million for the years ended December 31, 2022 and 2021, respectively. Stock-Based Compensation Expense Stock-based compensation expense related to awards granted under the 2014 Plan, including the RSAs, the 2020 Plan, the 2022 Inducement Plan, and the 2020 ESPP was classified in the consolidated statements of operations and comprehensive loss as follows (in thousands): Years Ended December 31, 2022 2021 Research and development $ 12,462 $ 9,346 General and administrative 6,367 6,567 Total $ 18,829 $ 15,913 |