In January 2023, the Company entered into a securities purchase agreement (the “Securities Purchase Agreement”) with the institutional accredited investors named therein (the “Investors”), pursuant to which the Company issued and sold to the Investors in a private placement (the “Private Placement”) pre-funded warrants (the “Pre-Funded Warrants”) to purchase an aggregate of 3,090,909 shares (the “Warrant Shares”) of the Company’s common stock. Each Pre-Funded Warrant has an exercise price of $0.10 per Warrant Share. The purchase price per Pre-Funded Warrant was $5.40. The Company received net proceeds of $16.6 million in the Private Placement, after deducting $0.1 million of offering expenses.

The Pre-Funded Warrants issued in the Private Placement provide that the holder of the Pre-Funded Warrants will not have the right to exercise any portion of its Pre-Funded Warrants if such holder, together with its affiliates and any other persons whose beneficial ownership of common stock would be aggregated with the holder for purposes of Section 13(d) or Section 16 of the Securities Exchange Act of 1934, as amended, would beneficially own in excess of 35% of the number of shares of common stock outstanding immediately after giving effect to such exercise. The Warrant Shares will also be subject to certain registration rights under the Company’s Amended and Restated Investors’ Rights Agreement. As of June 30, 2023, none of the Pre-Funded Warrants have been exercised.

In February 2023, in connection with entering into the Purchase Agreement with its founder, a related party who is the former chief executive officer of the Company and a greater than 5% owner of the Company's common stock at the time of the transaction, and other stockholders, the Company repurchased 908,644 shares of common stock for an aggregate price of $3.0 million. The repurchased common stock was subsequently retired in March 2023. The Company recorded the shares repurchased using the cost method.

In December 2019, the board of directors of the Company (the “Board”) adopted the 2019 Equity Incentive Plan (the “2019 Plan”). The 2019 Plan provides for the grant of share-based awards, including stock options and restricted stock units, to employees, directors and non-employee service providers of the Company. The number of shares of common stock reserved for issuance under the 2019 Plan automatically increases on January 1 of each calendar year, starting on January 1, 2020 and continuing through January 1, 2029, in an amount equal to the least of (i) 5% of the total number of shares of the Company’s capital stock issued and outstanding on the last day of the calendar month before the date of each automatic increase; (ii) 100,000 shares; or (iii) a lesser number of shares determined by the Company’s board of directors. Subject to this provision, the Company added 182,490 shares available for grant to the 2019 Plan effective January 1, 2023. As of June 30, 2023, there were approximately 610,959 shares available for future grants under the 2019 Plan.

In January 2021, the Board adopted the 2021 Employee Stock Purchase Plan (the “2021 ESPP”). The purpose of the 2021 ESPP is to secure the services of new employees, to retain the services of existing employees and to provide incentives for such individuals to exert maximum efforts toward the Company’s success. The ESPP is intended to qualify as an “employee stock purchase plan” within the meaning of Section 423 of the Code for U.S. employees. The number of shares of common stock reserved for issuance under the 2021 ESPP automatically increases on January 1 of each calendar year, starting on January 1, 2022 and continuing through January 1, 2031, in an amount equal to the lesser of (i) 1% of the total number of shares of the Company’s capital stock issued and outstanding on the last day of the calendar month before the date of each automatic increase; or (ii) a lesser number of shares determined by the Board. Subject to this provision, the Company added 40,254 shares available for grant to the 2021 ESPP effective January 1, 2023. As of June 30, 2023, there were approximately 119,379 shares available for future grants under the 2021 ESPP. As of June 30, 2023, no shares of common stock had been purchased under the 2021 ESPP.

In March 2022, the Board adopted the 2022 Inducement Plan. The 2022 Inducement Plan is a non-stockholder approved stock plan under which the Company may grant equity awards to induce highly-qualified prospective officers and employees who are not currently employed by the Company to accept employment and provide them with a proprietary interest in the Company. The Company intends that the 2022 Inducement Plan be reserved for persons to whom the Company may issue securities without stockholder approval as an inducement pursuant to Nasdaq Marketplace Rule 5635(c)(4). The number of shares of common stock reserved for issuance under the 2022 Inducement Plan was initially determined to be 100,000 shares. As of June 30, 2023, there were 100,000 shares available for future grants under the 2022 Inducement Plan.

The weighted average fair value per share of options to purchase common stock granted was $3.83 and $9.10 for the six months ended June 30, 2023 and 2022, respectively.

At June 30, 2023, the total compensation cost related to unvested stock-based awards granted under the 2019 Plan but not yet recognized was approximately $2.0 million, which is expected to be recognized over a weighted-average period of approximately 3.1 years.

At June 30, 2023, the total compensation cost related to unvested restricted stock units granted under the 2019 Plan but not yet recognized was approximately $0.3 million, which is expected to be recognized over a weighted-average period of approximately 2.7 years.

The following table summarizes stock-based compensation expense, which was included in the Condensed Consolidated Statements of Operations and Comprehensive Loss as follows (in thousands):


	Three Months Ended June 30,				Six Months Ended June 30,
	2023		2022		2023		2022
Research and development	$	91	$	120	$	158	$	550
General and administrative		163		514		320		1,025
Total stock-based compensation expense	$	254	$	634	$	478	$	1,575