Stockholders' Equity | 9. Stockholders’ Equity July 2023 Underwritten Offering On July 27, 2023, the Company entered into an underwriting agreement with BofA Securities, Inc., Cowen and Company, LLC and Piper Sandler & Co., as representatives of the several underwriters named therein (collectively, the “Underwriters”), relating to an underwritten public offering of 14,375,000 shares of the Company's common stock, which included 1,875,000 shares issued upon the exercise in full by the underwriters of their option to purchase additional shares (the "July 2023 Shares"). The closing of the offering took place on August 1, 2023. All of the July 2023 Shares were sold by the Company. The offering price of the July 2023 Shares was $ 4.80 per share. Net proceeds from the sale and issuance of the July 2023 Shares were approximately $ 64.4 million, after deducting underwriting discounts and commissions and offering expenses. April 2022 Underwritten Offering On August 11, 2021, the Company filed a universal shelf registration statement on Form S-3, which was declared effective on August 23, 2021, (the "Registration Statement"). Under the Registration Statement, the Company may offer and sell up to $ 200.0 million of a variety of securities, including common stock, preferred stock, depositary shares, debt securities, warrants, subscription rights or units from time to time pursuant to one or more offerings at prices and terms to be determined at the time of the sale. On April 14, 2022, the Company entered into an underwriting agreement with Jefferies LLC and Cowen and Company, LLC, relating to an underwritten offering under the Registration Statement of 16,276,987 shares of the Company’s common stock (the "Shares") and, in lieu of common stock to certain investors, pre-funded warrants to purchase 3,523,013 shares of common stock. The closing of the offering took place on April 19, 2022. The offering price of the Shares was $ 3.69 per share and the offering price of the pre-funded warrants was $ 3.6899 per share underlying each pre-funded warrant. Warrants must be exercised by means of a cashless exercise. Net proceeds from the offering were approximately $ 68.3 million, after deducting underwriting discounts and commissions and offering expenses. On June 10, 2022, the Company and each holder of the pre-funded warrants entered into amended and restated pre-funded warrants solely to eliminate the seven-year expiration date of the pre-funded warrants. Each amended and restated pre-funded warrant is now exercisable for $ 0.0001 per share of common stock from the original date of issuance until the date the pre-funded warrant is exercised in full. All other terms of the pre-funded warrants remain unchanged. The pre-funded warrants contain standard adjustment provisions if certain corporate events were to happen. The pre-funded warrants are classified as a component of permanent equity and were recorded at the issuance date using a relative fair value allocation method. The pre-funded warrants are equity classified because they are freestanding financial instruments that are legally detachable and separately exercisable from the equity instruments, are immediately exercisable, do not embody an obligation for the Company to repurchase its shares, and permit the holders to receive a fixed number of shares of common stock upon exercise. In addition, such pre-funded warrants do not provide any guarantee of value or return. As of December 31, 2022, 197,251 pre-funded warrants had been exercised by means of cashless exercise in exchange for the issuance of 197,240 shares of the Company's common stock. As of December 31, 2023, the remaining 3,325,762 pre-funded warrants had been exercised by means of cashless exercise in exchange for the issuance of 3,325,644 shares of the Company's common stock. Open Market Sale Agreement In connection with the filing of the Registration Statement on August 11, 2021, the Company entered into an Open Market Sale Agreement with Jefferies LLC, as sales agent, pursuant to which the Company may offer and sell shares of its common stock with an aggregate offering price of up to $ 50.0 million under an “at-the-market” offering program. As of December 31, 2023 , the Company sold 3,553,995 shares of its common stock pursuant to the Open Market Sale Agreement for aggregate net proceeds of $ 21.2 million. Equity Incentive Plans In January 2017, the Company’s board of directors and stockholders adopted the 2017 Equity Incentive Plan, which was amended and restated in July 2017, (as so amended and restated, the “2017 Plan”), which provided for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock unit awards and other stock awards. The maximum number of shares of common stock that were authorized for issuance under the 2017 Plan was 2,730,496 . On July 17, 2020, the Company’s stockholders approved the 2020 Stock Incentive Plan (the “2020 Plan”), which became effective on July 23, 2020. The 2020 Plan provides for the grant of incentive stock options, non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, and other stock-based awards. The number of shares of the Company’s common stock reserved for issuance under the 2020 Plan was 1,588,315 shares, plus the 426,065 shares of common stock remaining available for issuance under the 2017 Plan as of July 23, 2020. The number of shares reserved under the 2020 Plan will be annually increased on each January 1 through January 1, 2030 by the lower of (i) 4 % of the number of shares of common stock outstanding on the first day of such fiscal year and (ii) an amount determined by the Company’s board of directors. As of the effective date of the 2020 Plan, no further awards will be made under the 2017 Plan. Any options or awards outstanding under the 2017 Plan are governed by their existing terms. The shares of the Company’s common stock subject to outstanding awards under the 2017 Plan that expire, terminate, or are otherwise surrendered, cancelled, forfeited, or repurchased by the Company at their original issuance price pursuant to a contractual repurchase right will be added back to the shares of common stock available for issuance under the 2020 Plan. No more than 1,588,315 shares of the Company’s common stock may be granted subject to incentive stock options under the 2020 Plan. On January 1, 2024 and 2023, the number of shares of common stock reserved under the 2020 Plan was increased by 2,470,750 shares and 1,615,774 shares, respectively. On February 27, 2023, the Company's board of directors adopted the 2023 Inducement Stock Incentive Plan (the "Inducement Plan"). The Inducement Plan provides for the grant of non-statutory stock options, stock appreciation rights, restricted stock awards, restricted stock units, and other stock-based awards to persons who (a) were not previously an employee or director or (b) are commencing employment with the Company following a bona fide period of non-employment, in either case, as an inducement material to such person ’s entry into employment with the Company and in accordance with the requirements of the Nasdaq Stock Market Rule 5635(c)(4). As of December 31, 2023, the maximum number of shares of the Company's common stock reserved for issuance under the Inducement Plan is 1,000,000 shares. For the years ended December 31, 2023 and 2022, the Company recognized stock-based compensation expense of $ 7.0 million and $ 7.7 million, respectively. The fair value of shares vested for the years ended December 31, 2023 and 2022 was $ 7.6 million and $ 9.0 million, respectively. Stock Options The following table summarizes stock option activity under the Company’s equity incentive plans since December 31, 2022: Options Weighted- Weighted- Aggregate (in years) (in thousands) Outstanding at December 31, 2022 4,687,811 $ 8.53 8.06 $ 18 Granted 3,019,590 4.53 Exercised ( 43,209 ) 2.70 Forfeited ( 627,526 ) 10.43 Outstanding at December 31, 2023 7,036,666 $ 6.68 7.71 $ 4,615 Exercisable at December 31, 2023 3,370,210 $ 8.05 6.37 $ 3,007 Vested and expected to vest at December 31, 2023 7,036,666 $ 6.68 7.71 $ 4,615 (1) The aggregate intrinsic value of stock options is calculated as the difference between the exercise price of the stock options and the fair value of the Company’s common stock for those stock options that had exercise prices lower than the fair value of the Company’s common stock. The weighted average grant date fair value of stock options granted in the years ended December 31, 2023 and 2022 was $ 3.47 per share and $ 3.45 per share, respectively. The aggregate intrinsic value of stock options exercised during the years ended December 31, 2023 and 2022 was $ 0.1 million and $ 0.5 million, respectively. The total unrecognized compensation cost related to outstanding employee option awards as of December 31, 2023 was $ 11.6 million and is expected to be recognized over a weighted average period of 2.8 years. For purposes of calculating stock-based compensation expense, the Company estimates the fair value of stock options using the Black-Scholes option-pricing model. This model incorporates various assumptions, including the expected volatility, expected term, and interest rates. The underlying assumptions used to value stock options granted to participants using the Black-Scholes option-pricing were as follows: Years Ended December 31, 2023 2022 Risk-free interest rate range 3.36 % to 4.67 % 1.59 % to 4.30 % Dividend yield 0 % 0 % Expected term of options (years) 5.5 to 6.48 5.08 to 6.48 Volatility rate range 87.26 % to 89.67 % 84.50 % to 87.15 % Expected Term – The expected term of stock options represents the weighted average period the stock options are expected to be outstanding. The Company uses the simplified method for estimating the expected term, which calculates the expected term as the average time-to-vesting and the contractual life of the options for stock options issued to participants. Expected Volatility – Due to the Company’s limited operating history and lack of company-specific historical or implied volatility, the expected volatility assumption was determined by examining the historical volatilities of a group of industry peers whose share prices are publicly available. The Company expects to continue using this approach until such time as it has adequate historical data regarding the volatility of its own traded stock price. Risk-Free Interest Rate – The risk-free rate assumption is based on U.S. Treasury instruments, the terms of which were consistent with the expected term of the Company’s stock options. Expected Dividend – The expected dividend assumption is based on the Company’s history and expectation of dividend payouts. The Company has not paid any dividends to date and does not intend to pay dividends. Fair Value of Common Stock – Following the Company's initial public offering, the fair value of the Company’s common stock has been determined based on the closing price of the Company’s common stock on the Nasdaq Global Select Market on the grant date, with consideration of whether there is material nonpublic information that could impact that estimated fair value when it is released. RSUs Activity related to restricted stock units ("RSUs") for the year ended December 31, 2023 is summarized in the table below: Number of Shares Outstanding as of January 1, 2023 — Granted 100,000 Canceled / Forfeited — Vested / Settled — Outstanding as of December 31, 2023 100,000 The weighted-average grant date fair value of RSUs granted in the year ended December 31, 2023 was $ 5.73 per share. The total unrecognized compensation cost related to outstanding RSUs as of December 31, 2023 was $ 0.5 million and is expected to be recognized over a weighted-average period of 3.2 years. Employee Stock Purchase Plan On July 17, 2020, the Company’s stockholders approved the 2020 Employee Stock Purchase Plan (the “ESPP”), which became effective on July 23, 2020. The ESPP initially provided participating employees with the opportunity to purchase up to an aggregate of 198,539 shares of the Company’s common stock. The number of shares of common stock reserved for issuance under the ESPP will increase each January 1 through January 1, 2031, in an amount equal to the lowest of (1) 397,079 shares of the Company’s common stock, (2) 1 % of the number of shares of the Company’s common stock outstanding on the first day of such fiscal year, and (3) an amount determined by the Company’s board of directors. On January 1, 2024 and 2023, the number of shares of common stock reserved under the ESPP was increased by 397,079 shares and 397,079 shares, respectively. The Company activated its first six month offering period under the ESPP on April 1, 2022. As of December 31, 2023, 116,972 shares have been purchased by employees under the ESPP. |