Note 2 - Cash, Cash Equivalents, and Investments (Details Textual) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022
Corporate Debt Securities [Member]
Debt Securities, Held-to-maturity, Premium Paid on Purchase	$ 15,233	$ 20,850	$ 6,280