Note 5 - Share-based Compensation - Noncash Stock Option Compensation (Details) - USD ($)	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Stock-based compensation	$ 330,639	$ 453,791
General and Administrative Expense [Member]
Stock-based compensation	319,335	388,662
Research and Development Expense [Member]
Stock-based compensation	11,304	65,129
Share-Based Payment Arrangement, Option [Member]
Stock-based compensation	276,540	453,791
Restricted Stock Units (RSUs) [Member]
Stock-based compensation	$ 54,099	$ 0