Note 6 - Stockholders' Equity and Dilutive Equity Instruments (Details Textual) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended
	Jul. 31, 2023	Jun. 30, 2023	Jun. 30, 2022
Out-of-the-money Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)		5,923,399	5,923,399
Series A Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)		2,400,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 57.06
Series B Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)		2,600,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 62.28
GLF Equity Warrants [Member]
Class of Warrant or Right, Outstanding (in shares)		900,000
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 100.00
Series A and B Warrants [Member] | Subsequent Event [Member]
Class of Warrant or Right, Outstanding (in shares)	2,000,000.0
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	1,900,000
Proceeds from Warrant Exercises	$ 111.5
Class of Warrant or Right, Expired (in shares)	3,100,000