Note 6 - Stock-based Compensation Expense

3 Months Ended

Mar. 31, 2023

Notes to Financial Statements

Share-Based Payment Arrangement [Text Block]

6. Stock-Based Compensation Expense

Stock-based compensation expense related to stock options is recognized on a straight-line basis over the requisite service period for the award and is allocated to research and development expense or general and administrative expense based upon the classification of the individual to whom the award is granted. Stock-based compensation expense related to stock option grants was $228,039 and $190,191 during the three-month periods ended March 31, 2023 and 2022, respectively, and as of March 31, 2023, there is $1,221,367 of unrecognized compensation expense that we expect to recognize over a weighted-average period of 1.8 years.

We have also issued shares of our restricted common stock to consultants and recognize the related expense over the terms of the related agreements. During the three-month periods ended March 31, 2023 and 2022 we recorded stock-based compensation expense of $18,000 and $14,960, respectively, associated with common stock issued for consulting services. As of March 31, 2023, there is $81,000 recorded as a prepaid expense for these arrangements, which will be recognized as expense over the terms of the related agreements.