On December 29, 2017, the 2017 Equity Incentive Plan was approved by the stockholders of the Company, which currently allows for issuance of up to approximately 17,000 shares of common stock underlying stock options granted prior to September 10, 2019. The 2017 Equity Incentive Plan was terminated upon the approval of the 2019 Equity Incentive Plan ("2019 Equity Plan") subject to outstanding stock options granted under the 2017 Equity Incentive Plan that remain exercisable through maturity for the Company's employees and directors.

On September 10, 2019, the 2019 Equity Plan was approved by the stockholders of the Company. On June 20, 2023, an amendment to the 2019 Equity Plan was approved by the stockholders of the Company, which amended and restated the 2019 Equity Plan (as amended and restated, the "2023 Amended and Restated Equity Incentive Plan"). The 2023 Amended and Restated Equity Incentive Plan currently allows for issuance of up to approximately 6,036,000 shares of common stock in connection with the grant of stock-based awards, including stock options, restricted stock, restricted stock units, stock appreciation rights and other types of awards as deemed appropriate.

The following table summarizes the components of stock-based compensation expense in the consolidated statements of operations for the three months ended March 31, 2026 and 2025 (in thousands):


	Total Number of Shares (In Thousands)	Weighted Average Exercise Price		Weighted Average Remaining Contractual Term (In Years)	Aggregate Intrinsic Value (In Thousands)
Outstanding at December 31, 2025	2,651	$	3.19


Canceled	(2)	0.87
Outstanding at March 31, 2026	2,649	$	3.19	7.20	$	5,801
Vested and exercisable at March 31, 2026	1,778	$	4.21	6.67	$	3,084

The aggregate intrinsic values of outstanding and exercisable stock options at March 31, 2026 were calculated based on the closing price of the Company’s common stock as reported on The Nasdaq Capital Market on March 31, 2026 of $4.23 per share. The aggregate intrinsic value equals the positive difference between the closing fair market value of the Company’s common stock and the exercise price of the underlying stock options.

The Company uses the Black-Scholes option-pricing model to determine the fair value of all its stock options granted. The weighted average assumptions used during the three months ended March 31, 2026 and 2025, were as follows:


	Three Months Ended March 31,
		2026	2025
Risk free interest rate		n/a	4.25	%
Volatility		n/a	122.43	%
Expected term (years)		n/a	6.17
Expected dividend yield		n/a	—	%

There were no options granted during the three months ended March 31, 2026. The weighted-average grant date fair value of options granted during the three months ended March 31, 2025 was $0.85.

The Company’s expected common stock price volatility assumption is based upon the historical volatility of the Company's publicly traded common stock. The expected term assumption for employee grants is based upon the simplified method, which averages the contractual term of the Company’s options of ten years with the average vesting term of four years for an average of approximately six years. The expected term assumption for non-employees is based upon the contractual term of the option. The dividend yield assumption is zero because the Company has never paid cash dividends and presently has no intention to do so. The risk-free interest rate used for each grant is also based upon prevailing short-term interest rates. The Company accounts for forfeitures as they occur.

As of March 31, 2026, there was approximately $0.8 million of unrecognized compensation cost related to outstanding stock options that is expected to be recognized as a component of the Company’s operating expenses over a weighted-average period of 2.0 years.


	Shares (In Thousands)	Weighted Average Grant Date Fair Value
Unvested at December 31, 2025	897	$	1.09
Granted	1,365	$	4.04

Unvested at March 31, 2026	2,262	$	2.87

As of March 31, 2026, there was approximately $5.8 million of unrecognized compensation cost related to outstanding RSUs that is expected to be recognized as a component of the Company's operating expenses over a weighted-average period of 3.0 years. No RSUs vested during the three months ended March 31, 2026.

On April 22, 2021, the Board of Directors adopted the 2021 Employee Stock Purchase Plan ("2021 ESPP"), which was approved by the Company's stockholders on June 8, 2021 and authorized the issuance of up to 300,000 shares of common stock pursuant to the 2021 ESPP. The 2021 ESPP allows employees to contribute up to 20% of their cash earnings, subject to a maximum of $25,000 per year under Internal Revenue Service rules, to be used to purchase shares of the Company’s common stock on semi-annual purchase dates. The 2021 ESPP allows eligible employees to purchase shares of common stock at a price per share equal to 85% of the lower of the fair market value of the common stock at the beginning or end of each six-month offering period during the term of the 2021 ESPP.

On June 17, 2025, an amendment to the 2021 ESPP was approved by the stockholders of the Company, which amended and restated the 2021 ESPP (as amended and restated, the "Amended and Restated 2021 ESPP") to increase the number of shares of common stock available for sale under the 2021 ESPP by 800,000.

During the three months ended March 31, 2026, 45,850 shares of common stock were purchased by employees under the Amended and Restated 2021 ESPP for proceeds of approximately $0.1 million. There are approximately 718,000 shares of common stock reserved for issuance under the Amended and Restated 2021 ESPP as of March 31, 2026.