Note L – Share-based Compensation Plans

We primarily use the Black-Scholes option pricing model to value stock options granted to employees and non-employees, including stock options granted to members of our Board of Directors. However, the fair value of stock option market-based awards is

calculated based on a Monte Carlo simulation as of the date of issuance. All stock options have 10-year terms and generally vest ratably over a 3 or 4-year period.

The weighted average grant-date fair values of stock options granted during the three months ended March 31, 2026 and 2025 were $2.43 and $2.61, respectively.

During the three months ended March 31, 2026, all options were granted with exercise prices equal to the market value of the underlying shares of common stock on the grant date.

As of March 31, 2026, there was approximately $2.0 million of total unrecognized share-based compensation expense related to these stock options and stock options granted under a subsidiary plan which, if all milestones are achieved, will be recognized over a weighted average period of 1.3 years.

Certain employees and consultants have been granted non-vested stock. The fair value of non-vested market-based awards is calculated based on a Monte Carlo simulation as of the date of issuance. The fair value of other non-vested stock is calculated based on the closing sale price of our common stock on the date of issuance.

As of March 31, 2026, there was approximately $0.1 million of unrecognized share-based compensation expense related to these non-vested shares and non-vested shares granted under a subsidiary plan which will be recognized over a period of 0.8 years.

During the three months ended March 31, 2026, 20,528 shares were issued under the 2019 Employee Stock Purchase Plan and 428,045 shares were issued as a result of the vesting of non-vested stock.