Note 9 - Net Loss Per Share of Common Stock (Details Textual) - shares	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Weighted Average Number of Shares Outstanding, Diluted, Adjustment, Total (in shares)	0	0
Pre-funded Warrants Related to Private Placement [Member]
Class of Warrant or Right, Outstanding (in shares)	15,870,199