Note 16 - Equity Incentive Plans

6 Months Ended

Jun. 30, 2026

Notes to Financial Statements

Share-Based Payment Arrangement [Text Block]

16. Equity Incentive Plans

2017 Equity Incentive Plan

In 2017, the Company adopted its 2017 Equity Incentive Plan (the “2017 Plan”).

On November 10, 2021, the 2017 Plan terminated and was replaced by the 2021 Plan (defined below), and future issuances of incentive instruments will be governed by the 2021 Plan. To the extent that outstanding awards under the 2017 Plan are forfeited or lapse unexercised, the shares of common stock subject to such awards will no longer be available for future issuance.

2021 Equity Incentive Plan

In 2021, the Company adopted the 2021 Equity Incentive Plan (the “2021 Plan”). The plan allows for the issuance of incentive stock options, nonstatutory stock options, restricted stock awards, restricted stock units, stock bonus awards and performance-based awards. Awards granted under the 2021 Plan are determined by the Compensation Committee of the Company’s board of directors, who is responsible for administering the 2021 Plan. The term for stock options shall be no more than ten years from the date of grant. In the case of an Incentive Stock Option granted to an optionee who, at the time the option is granted, owns stock representing more than 10% of the voting power of all classes of stock of the Company or any Parent or Subsidiary, the term of the option shall be five years from the date of grant or such shorter term as may be provided in the option Agreement. To the extent outstanding awards under the 2021 Plan are forfeited or lapse unexercised, the shares of common stock subject to such awards will be available for future issuance under the 2021 Plan. The 2021 Plan provides that additional shares will automatically be added to the shares authorized for issuance under the 2021 Plan on January 1 of each year. The number of shares added each year will be equal to the lesser of: (i) 5.0% of the outstanding shares of the Company’s common stock on December 31st of the preceding calendar year or (ii) such number of shares determined by the board of directors, in its discretion. On January 1, 2024, 4,312 shares were automatically added to the number of shares authorized for issuance under 2021 Plan (an increase equal to 5% of the number of the outstanding shares of Company common stock as of December 31, 2023).

Amended and Restated 2021 Equity Incentive Plan, as amended

On August 9, 2024, the Company adopted its Amended and Restated 2021 Equity Incentive Plan (the “A&R 2021 Plan”), which amended and restated the 2021 Plan in full to, amongst other things, increase the number of shares of common stock authorized for issuance thereunder from 5,434 shares to 58,823 shares. The Company’s board of directors unanimously approved the adoption of the A&R 2021 Plan, subject to stockholder approval, on June 15, 2024, and the Company’s stockholders approved the A&R 2021 Plan at the Company’s 2024 Annual Meeting of Stockholders held on August 9, 2024. On January 1, 2025, 27,846 shares were automatically added to the number of shares authorized for issuance under A&R 2021 Plan (an increase equal to 5% of the number of the outstanding shares of Company common stock as of  December 31, 2025). On January 1, 2026, 126,289 shares were automatically added to the number of shares authorized for issuance under A&R 2021 Plan (an increase equal to 5% of the number of the outstanding shares of Company common stock as of  December 31, 2025).

On June 30, 2025, following stockholder approval, the Company further amended the A&R 2021 Plan to increase the number of shares of common stock authorized for issuance thereunder from 86,669 to 511,669 shares. On May 28, 2026, following stockholder approval, the Company further amended the A&R 2021 Plan to increase the number of shares of common stock authorized for issuance thereunder from 637,958 to 3,219,566 shares.

As of  June 30, 2026, there were 2,774,278 shares of common stock available for issuance under the A&R 2021 Plan, as amended.

Stock Options

In the case of an incentive stock option (i) granted to an employee who, at the time of grant of such option, owns stock representing more than 10% of the voting power of all classes of stock of the Company or any parent or subsidiary of the Company, the exercise price shall be no less than 110% of the fair market value per share on the date of grant; (ii) granted to any other employee, the per share exercise price shall be no less than 100% of the fair market value per share on the date of grant. In the case of a non-statutory stock option (i) granted to an employee who, at the time of grant of such option, owns stock representing more than 10% of the voting power of all classes of stock of the Company or any parent or subsidiary of the Company, the exercise price shall be no less than 110% of the fair market value per share on the date of grant; (ii) granted to any other service provider, the per share exercise price shall be no less than 100% of the fair market value per share on the date of grant. Notwithstanding the foregoing, options may be granted with a per share exercise price other than as required above pursuant to a merger or other corporate transaction.

The options may include provisions permitting exercise of the option prior to full vesting. Any unvested shares upon termination shall be subject to repurchase by the Company at the original exercise price of the option. Stock options granted under the Company’s equity incentive plans generally vest over four years from the date of grant.

The following table summarizes the stock option award activity for the six months ended June 30, 2026:

	Outstanding			Exercisable
Balance as of January 1, 2026		392,494			16,948
Granted		45,000			—
Vested		—			46,897
Cancelled or expired		(81,492	)		(3,218	)
Exercised		—			—
Balance as of June 30, 2026		356,002			60,627

The weighted-average exercise price as of  June 30, 2026 for stock options outstanding and stock options exercisable was $6.13 and $22.63, respectively. The weighted average remaining contractual life as of  June 30, 2026 for stock options outstanding and stock options exercisable was 8.38 and 4.04 years, respectively. Stock-based compensation expense related to stock options was $63 thousand and $206 thousand for the three and six months ended June 30, 2026, respectively. Stock-based compensation expense related to stock options was $57 thousand and $131 thousand for the three and six months ended June 30, 2025, respectively. As of  June 30, 2026, there was $576 thousand of remaining expense, which is expected to be amortized over 3.16 years.

Restricted Stock Awards

There was no restricted stock award activity, and no restricted stock awards outstanding, during the six months ended June 30, 2026.  During the six months ended June 30, 2025, a total of 111 restricted stock awards vested and $2 thousand of stock-based compensation was recorded. There were no remaining restricted stock awards outstanding as of June 30, 2025.  

Restricted Stock Units

The following table sets forth the status of the Company’s restricted stock units issued to employees for the six months ended June 30, 2026:

	Number of Shares			Weighted- Average Grant Date Fair Value Per Share
Non-vested as of January 1, 2026		50,736		$	5.96
Granted		61,729		$	0.81
Vested		(76,621	)	$	2.09
Forfeited		(7,350	)	$	3.84
Cancelled		—		$	—
Non-vested as of June 30, 2026		28,494		$	7.95

The fair value of restricted stock units granted during each of the three and six months ended June 30, 2026 was $50 thousand. The fair value of restricted stock units granted during each of the three and six months ended June 30, 2025 was $306 thousand. Stock-based compensation expense related to restricted stock units was $70 thousand and $135 thousand for the three and six months ended June 30, 2026 , respectively. Stock-based compensation expense related to restricted stock units was $33 thousand and $57 thousand for the three and six months ended June 30, 2025 , respectively. As of  June 30, 2026, there was $203 thousand of remaining expense, which is expected to be amortized over 2.62 years.

Total Stock-Based Compensation

Total stock-based compensation recorded in the condensed consolidated statements of operations is allocated as follows (in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2026		2025		2026		2025
Research and development	$	11	$	59	$	47	$	102
Selling, general and administrative		122		118		294		175
Total stock-based compensation	$	133	$	177	$	341	$	277