Stockholders' Equity | Stockholders’ Equity Common Stock As of September 30, 2024, there were 65,500,134 shares of common stock outstanding. Each share of common stock is entitled to one vote. The holders of the common stock are also entitled to receive dividends whenever funds are legally available and when declared by the Company's board of directors. 2019 Equity Incentive Plan On June 15, 2019, the Company's board of directors approved, and on August 1, 2019 the Company's stockholders approved, the Company's 2019 Equity Incentive Plan (as amended, the "2019 Plan"). The 2019 Plan is the successor to and continuation of the Company's 2012 Equity Incentive Plan. The number of shares authorized for issuance under the 2019 Plan may be increased by (a) the shares subject to outstanding stock awards granted under the Company’s 2009 Equity Incentive Plan (the “2009 Plan”) and the Company’s 2012 Equity Incentive Plan (together with the 2009 Plan, the “Prior Plans”) that on or after the effective date of the 2019 Plan (i) expire or terminate for any reason prior to exercise or settlement; (ii) are forfeited because of the failure to meet a contingency or condition required to vest such shares or otherwise return to the Company, or (iii) are reacquired, withheld (or not issued) to satisfy a tax withholding obligation in connection with an award or to satisfy the purchase price or exercise price of a stock award. No further grants will be made under the Prior Plans. In addition, on January 22, 2020, an additional 416,686 shares of common stock became available for issuance under the 2019 Plan pursuant to the second closing under our May 2019 securities purchase agreement. Further, on January 1st of each year, beginning on January 1, 2021 and ending on January 1, 2024, the number of shares authorized for issuance under the 2019 Plan was increased by 5.0% of the total number of shares of our capital stock outstanding on December 31 of the preceding calendar year or a lesser number of shares as may be determined by the Company's board of directors. Beginning on January 1, 2025, on January 1st of each year through (and including) January 1, 2029 (the “Evergreen Mechanism”), the number of shares authorized for issuance under the 2019 Plan will be increased by 5.0% of the sum of (x) the total number of shares of common stock outstanding on December 31st of the preceding calendar year (without regard to any beneficial ownership limitations applicable thereto) plus (y) the total number of shares of common stock issuable upon conversion of shares of convertible preferred stock outstanding on December 31st of the preceding calendar year plus (z) the total number of shares of common stock issuable upon cash exercise of prefunded warrants outstanding on December 31st of the preceding calendar year (without regard to any beneficial ownership limitations applicable thereto). On June 13, 2023, our stockholders approved an amendment to the 2019 Plan, which authorized an additional 5,000,000 shares of common stock available for issuance thereunder. On May 16, 2024, our stockholders approved an amendment to the 2019 Plan, which authorized an additional 9,500,000 shares of common stock available for issuance thereunder and approved the Evergreen Mechanism. As of September 30, 2024, 3,069,499 shares of common stock were available for new equity award grants under the 2019 Plan and 13,564,643 shares of common stock were reserved for issuance pursuant to equity awards outstanding under the 2019 Plan as of September 30, 2024. 2021 Inducement Plan On November 23, 2021, the Company's board of directors adopted the 2021 Inducement Plan (the “Inducement Plan”), which became effective immediately. Stockholder approval of the Inducement Plan was not required pursuant to Rule 5635(c)(4) of the Nasdaq Listing Rules. The Inducement Plan initially reserved 200,000 shares of common stock and provides for the grant of non-qualified stock options that was used exclusively for grants to individuals that were not previously employees or directors of the Company, as an inducement material to the individual’s entry into employment with the Company. The authorized number of shares available for grant under the Inducement Plan was subsequently increased in October 2022 to 540,000 shares in the aggregate, and subsequently increased again in December 2023 to 1,030,000 shares in the aggregate. Under the Inducement Plan, options are granted with varying vesting terms, but typically vested over four years, with 25% of the total grant vesting on the first anniversary of the effective date of the option grant and the remaining grant vesting monthly thereafter over the following 36 months. As of September 30, 2024, 500,000 shares of common stock were reserved for future issuance under the Inducement Plan and 530,000 shares of common stock were reserved for future issuance pursuant to equity awards outstanding under the Inducement Plan. 2022 Employee Stock Purchase Plan In June 2022, our stockholders approved and we adopted the 2022 Employee Stock Purchase Plan (the “2022 Purchase Plan”), which enables participants to contribute up to 15% of such participant’s eligible compensation during a defined rolling six-month periods to purchase our common stock. The purchase price of common stock under the 2022 Purchase Plan will be the lesser of: (i) 85% of the fair market value of our common stock at the inception of the enrollment period or (ii) 85% of the fair market value of our common stock at the applicable purchase date. The 2022 Purchase Plan supersedes the 2012 Employee Stock Purchase Plan, and no further offerings will be made under the 2012 Employee Stock Purchase Plan. As of September 30, 2024, a maximum of 133,054 shares of our common stock were reserved for future issuance and have been authorized for purchase under the 2022 Purchase Plan. 2024 Private Placement of Common Stock and Non-Voting Preferred Stock On March 11, 2024, we entered into a Securities Purchase Agreement (the “March 2024 SPA”) with certain institutional and other accredited investors (the “2024 Purchasers”), pursuant to which we agreed to sell and issue shares of our common stock and shares of our newly designated non-voting Class A-6 convertible preferred stock in a private placement transaction (the "2024 PIPE"). At the closing under the March 2024 SPA that occurred on March 14, 2024 (the “2024 Closing”), we sold and issued to the 2024 Purchasers (i) 45,108,667 shares of common stock at a purchase price of $1.60 per share, and (ii) 173,915 shares of non-voting Class A-6 convertible preferred stock, in lieu of shares of common stock, at a price of $160.00 per share. The Company received net proceeds of approximately $93.9 million in the 2024 PIPE after deducting placement agent and financial advisor fees and other expenses. Each share of non-voting Class A-6 convertible preferred stock is convertible into 100 shares of common stock, subject to certain beneficial ownership conversion limitations. Stelios Papadopoulos, Ph.D., Chairman of the Company's board of directors, was a 2024 Purchaser under the March 2024 SPA and purchased 250,000 shares of common stock for $0.4 million. We evaluated the non-voting Class A-6 convertible preferred stock sold in the 2024 PIPE under Accounting Standards Codification ("ASC") 480, Distinguishing Liabilities from Equity, and ASC 815, Derivatives and Hedging, and determined permanent equity treatment was appropriate for these freestanding financial instruments and there were no embedded features that required bifurcation. 2023 Private Placement of Common Stock and Non-Voting Preferred Stock On April 13, 2023, we entered into a Securities Purchase Agreement (the “April 2023 SPA”) with certain institutional and other accredited investors (the “2023 Purchasers”), pursuant to which we agreed to sell and issue shares of our common stock and shares of our newly designated non-voting Class A-5 convertible preferred stock in a private placement transaction (the "2023 PIPE"). At the closing under the April 2023 SPA that occurred on April 13, 2023 (the “2023 Closing”), we sold and issued to the 2023 Purchasers (i) 2,615,536 shares of common stock at a purchase price of $0.9001 per share, and (ii) 140,827 shares of non-voting Class A-5 convertible preferred stock, in lieu of shares of common stock, at a price of $90.01 per share. Total gross proceeds from the 2023 Closing were approximately $15.0 million. Each share of non-voting Class A-5 convertible preferred stock is convertible into 100 shares of common stock, subject to certain beneficial ownership conversion limitations. Stelios Papadopoulos, Ph.D., Chairman of the Company's board of directors, was a 2023 Purchaser under the April 2023 SPA and purchased 222,198 shares of common stock for $0.2 million. We evaluated the non-voting Class A-5 convertible preferred stock sold in the 2023 PIPE under ASC 480, Distinguishing Liabilities from Equity, and ASC 815, Derivatives and Hedging, and determined permanent equity treatment was appropriate for these freestanding financial instruments and there were no embedded features that required bifurcation. Additional Outstanding Non-Voting Preferred Stock and Warrants On May 7, 2019, we sold and issued (i) 973,045 shares of common stock (ii) 415,898 shares of non-voting Class A-1 convertible preferred stock and (iii) accompanying warrants to purchase an aggregate of 1,388,943 shares of common stock. Each share of non-voting Class A-1 convertible preferred stock is convertible into one share of common stock, subject to certain beneficial ownership conversion limitations. The warrants were exercisable for a period of five years following the date of issuance and had an exercise price of $10.80 per share, subject to proportional adjustments in the event of stock splits or combinations or similar events. The warrants were also exercisable on a net exercise "cashless" basis. The warrants expired on May 7, 2024. On December 24, 2019, we sold and issued 3,288,390 shares of non-voting Class A-2 convertible preferred stock and accompanying warrants to purchase an aggregate of 3,288,390 shares of common stock. Each share of non-voting Class A-2 convertible preferred stock is convertible into one share of common stock, subject to certain beneficial ownership conversion limitations. The warrants are exercisable for a period of five years following the date of issuance and have an exercise price of $6.66 per share, subject to proportional adjustments in the event of stock splits or combinations or similar events. The warrants are also exercisable on a net exercise “cashless” basis. On December 4, 2020, we sold and issued (i) 2,434,152 shares of common stock (ii) 272,970 shares of non-voting Class A-3 convertible preferred stock and (iii) accompanying warrants to purchase an aggregate of 2,030,341 shares of common stock. Each share of non-voting Class A-3 convertible preferred stock is convertible into one share of common stock, subject to certain beneficial ownership conversion limitations. The warrants are exercisable for a period of five years following the date of issuance and have an exercise price of $7.46 per share, subject to proportional adjustments in the event of stock splits or combinations or similar events. The warrants are also exercisable on a net exercise "cashless" basis. On November 30, 2021, we sold and issued (i) 5,892,335 shares of common stock and (ii) 3,725,720 shares of non-voting Class A-4 convertible preferred stock. Each share of non-voting Class A-4 convertible preferred stock is convertible into one share of common stock, subject to certain beneficial ownership conversion limitations. ATM Offering On December 12, 2018, we entered into a Common Stock Sales Agreement (the “Stock Sales Agreement”) with H.C. Wainwright & Co., LLC (“HCW”), pursuant to which we may sell and issue shares of our common stock from time to time through HCW, as our sales agent (the “ATM Offering”). We have no obligation to sell any shares of common stock in the ATM Offering, and may, at any time, suspend offers under the Stock Sales Agreement or terminate the Stock Sales Agreement. Subject to the terms and conditions of the Stock Sales Agreement, HCW will use its commercially reasonable efforts to sell shares of our common stock from time to time based upon our instructions (including any price, time or size limits or other parameters or conditions that we may impose, subject to certain restrictions). We pay HCW a commission of 3.0% of the gross sales price of any shares sold under the Stock Sales Agreement. No shares were sold under the ATM Offering during the three and nine months ended September 30, 2024. A total of 716,000 and 725,192 shares were sold and settled under the ATM Offering during the three and nine months ended September 30, 2023, respectively, for proceeds of $1.1 million for each the three and nine months ended September 30, 2023. Shares Reserved for Future Issuance The following shares of common stock were reserved for future issuance as of September 30, 2024 (in thousands): Class A-1 convertible preferred stock outstanding (as-converted) 257 Class A-2 convertible preferred stock outstanding (as-converted) 1,331 Class A-3 convertible preferred stock outstanding (as-converted) 259 Class A-4 convertible preferred stock outstanding (as-converted) 3,726 Class A-5 convertible preferred stock outstanding (as-converted) 14,083 Class A-6 convertible preferred stock outstanding (as-converted) 17,392 Warrants to purchase Common Stock 4,909 Common stock options outstanding 14,108 RSUs outstanding 1,389 Common stock available for future grant under the 2019 Equity Incentive Plan 3,069 Common stock available for future grant under the 2021 Inducement Plan 500 2022 Employee Stock Purchase Plan 133 Total common shares reserved for future issuance 61,156 The following table summarizes our stock option, performance stock award and RSU (together, "Stock Awards") activity under all equity incentive plans for the nine months ended September 30, 2024 (shares in thousands): Number of Weighted Number of Weighted average grant date fair value Stock Awards outstanding at December 31, 2023 6,188 $ 2.58 1,161 $ 1.38 Granted 8,008 $ 1.92 372 $ 1.30 Exercised (options) or Vested (RSUs) (2) $ 1.40 (113) $ 1.48 Canceled/forfeited/expired (86) $ 3.85 (31) $ 1.34 Stock Awards outstanding at September 30, 2024 14,108 $ 2.20 1,389 $ 1.35 Stock-Based Compensation The following table summarizes the weighted average assumptions used to estimate the fair value of stock options and performance stock awards granted to employees under the 2019 Plan, the Inducement Plan and the shares purchasable under the 2022 Purchase Plan during the periods presented: Three months ended Nine months ended 2024 2023 2024 2023 Stock options Risk-free interest rate 4.0 % 4.2 % 4.4 % 4.1 % Volatility 96.6 % 96.3 % 96.2 % 96.4 % Dividend yield — — — — Expected term (years) 6.1 6.1 6.0 6.1 Performance stock options Risk-free interest rate — — 4.5 % — Volatility — — 96.3 % — Dividend yield — — — — Expected term (years) 0 0 6.3 0 Employee stock purchase plan shares Risk-free interest rate 5.1 % 5.1 % 5.3 % 4.7 % Volatility 90.8 % 81.0 % 95.3 % 85.7 % Dividend yield — — — — Expected term (years) 0.5 0.5 0.5 0.5 The following table summarizes the allocation of our stock-based compensation expense for all Stock Awards during the periods presented (in thousands): Three months ended Nine months ended 2024 2023 2024 2023 Research and development $ 1,018 $ 311 $ 2,109 $ 638 General and administrative 1,404 662 3,163 1,127 Total $ 2,422 $ 973 $ 5,272 $ 1,765 |