Stock Plans and Stock-Based Compensation | Stock Plans and Stock-Based Compensation As of September 30, 2024, the Company had two stockholder-approved, stock-based compensation plans: (i) the Fifth Amended and Restated 2010 Stock Incentive Plan (“2010 Plan”) and (ii) the Amended and Restated 2010 Employee Stock Purchase Plan, as amended (“ESPP”). New employees are generally issued options as an inducement equity award under Nasdaq Listing Rule 5635(c)(4) outside of the 2010 Plan (“Inducement Awards”). The Fifth Amended and Restated 2010 Stock Incentive Plan The 2010 Plan permits the granting of incentive and non-qualified stock options and stock awards to employees, officers, directors, and consultants of the Company and its subsidiaries at prices determined by the Company’s board of directors. In May 2024, the Company's stockholders approved the amendment and restatement of the 2010 Plan to reserve an additional 942,100 shares of common stock for issuance under the 2010 Plan. The Company can issue up to 2,101,600 shares of its common stock pursuant to awards granted under the 2010 Plan. Options vest and become exercisable based on a schedule determined by the board of directors and expire up to ten years from the date of grant. The 2010 Plan uses a “fungible share” concept under which each share of stock subject to awards granted as options and stock appreciation rights (“SARs”) will cause one share per share under the award to be removed from the available share pool, while each share of stock subject to awards granted as restricted stock, restricted stock units, other stock-based awards or performance awards where the price charged for the award is less than 100% of the fair market value of the Company’s common stock will cause 1.3 shares per share under the award to be removed from the available share pool. As of September 30, 2024, the Company has only granted options to purchase shares of the Company’s common stock with an exercise price equal to the closing market price of the Company’s common stock on the Nasdaq Capital Market on the grant date and issued restricted stock awards ("RSAs") at no cost to Company employees, excluding officers. As of September 30, 2024, 956,366 shares remained available for grant under the 2010 Plan. During the nine months ended September 30, 2024, the Company’s board of directors granted options to purchase 457,670 shares of the Company’s common stock to officers and employees of the Company under the 2010 Plan. These options vest and become exercisable as to 25% of the shares underlying the awards after the first year and as to an additional 6.25% of the shares underlying the awards in each subsequent quarter, based upon continued employment over a four year period, and are exercisable at a price equal to the closing market price of the Company’s common stock on the grant date. During the nine months ended September 30, 2024, the Company’s board of directors granted options to its non-employee directors to purchase 21,250 shares of common stock under the 2010 Plan, which will vest and become exercisable in one year from the date of grant. These options were granted at an exercise price that equaled the closing market price of the Company’s common stock on the grant date. Inducement Awards The Company grants Inducement Awards to certain new employees. These options generally vest as to 25% of the shares underlying the option on the first anniversary of the grant date, and as to an additional 6.25% of the shares underlying the option on each successive quarter thereafter. During the nine months ended September 30, 2024, the Company’s board of directors granted Inducement Awards to purchase 39,350 shares of common stock. These options are granted at an exercise price that equals the closing market price of the Company’s common stock on the grant date. Stock Options A summary of stock option activity under the 2010 Plan and Inducement Awards are summarized as follows: Number of Weighted Weighted Aggregate Intrinsic Value Outstanding, December 31, 2023 840,880 $ 47.58 7.16 Granted 518,270 11.39 Exercised — — Canceled/Forfeited (198,899) 45.82 Outstanding, September 30, 2024 1,160,251 $ 33.44 7.45 $ 1 Exercisable at September 30, 2024 551,464 $ 55.86 5.65 $ — Vested and unvested expected to vest at September 30, 2024 1,160,251 $ 33.44 7.45 $ 1 The weighted average grant date fair values of the stock options granted during the nine months ended September 30, 2024 and 2023 were $9.50 and $12.00, respectively, and were calculated using the following estimated assumptions under the Black-Scholes option pricing model: Nine Months Ended 2024 2023 Expected term (years) 6 5.5 Risk free interest rate 3.9% - 4.5% 3.5% - 3.6% Expected volatility 114% - 116% 115% - 116% Expected dividends None None As of September 30, 2024, there was $6.8 million of unrecognized compensation cost related to unvested employee stock option awards outstanding, which is expected to be recognized as expense over a weighted average period of 2.4 years. There were no employee stock options exercised during the nine months ended September 30, 2024. The intrinsic value of employee stock options exercised during the nine months ended September 30, 2023 was not material. Restricted Stock Awards The following table presents a summary of unvested RSAs under the 2010 Plan as of September 30, 2024: Number of Shares Weighted Average Grant Date Fair Value Unvested, December 31, 2023 110,500 $ 18.20 Awarded — — Vested (65,988) 18.20 Forfeited (4,375) 18.20 Unvested, September 30, 2024 40,137 $ 18.20 As of September 30, 2024, there were 40,137 shares outstanding underlying RSAs that are expected to vest. As of September 30, 2024, there was $0.4 million of unrecognized compensation costs related to RSAs, which are expected to be recognized as expense over a remaining weighted average period of 0.6 years. The fair value of RSAs that vested during the nine months ended September 30, 2024 was $1.0 million. There were no RSAs that vested during the nine months ended September 30, 2023. The weighted average grant date fair value of RSAs granted during the nine months ended September 30, 2023 was $18.20. Amended and Restated 2010 Employee Stock Purchase Plan, as amended In May 2024, the Company's stockholders approved an amendment to the ESPP to reserve an additional 400,000 shares of common stock for issuance under the ESPP. The Company has reserved 500,000 shares of common stock for issuance under the ESPP. Eligible employees may purchase shares of the Company’s common stock at 85% of the lower closing market price of the common stock at the beginning of the enrollment period or ending date of the purchase period within a two-year enrollment period, as defined. The Company has four six-month purchase periods per each two-year enrollment period. If, within any one of the four purchase periods in an enrollment period, the purchase period ending stock price is lower than the stock price at the beginning of the enrollment period, the two-year enrollment resets at the new lower stock price. During the three and nine months ended September 30, 2024, 11,307 shares were issued under the ESPP. During the three and nine months ended September 30, 2023, 19,345 shares were issued under the ESPP. As of September 30, 2024, there were 415,324 shares available for future purchase under the ESPP. Stock-Based Compensation Expense For the three and nine months ended September 30, 2024 and 2023, the Company recorded stock-based compensation expense to the following line items in its costs and expenses section of the Condensed Consolidated Statements of Operations and Comprehensive Loss: Three Months Ended Nine Months Ended (in thousands) 2024 2023 2024 2023 Research and development expenses $ 624 $ 776 $ 2,168 $ 2,059 General and administrative expenses 760 857 2,479 2,393 Total stock-based compensation expense $ 1,384 $ 1,633 $ 4,647 $ 4,452 |