Note 5 - Stockholders' Equity (Details Textual) - USD ($)	Dec. 19, 2022	Mar. 31, 2023	Dec. 21, 2022	Nov. 09, 2022	Jun. 30, 2022
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001			$ 0.001
Preferred Stock, Shares Issued (in shares)		280,898			280,898	[1]
Treasury Stock, Common, Shares (in shares)		5,821			0
Treasury Stock, Common, Value		$ 69,000			$ (0)
Preferred Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001			$ 0.001	[1]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)		$ 72.10			$ 72.10
Equity Securities, Minimum Closing Bid Price (in dollars per share)	$ 1.00
Equity Securities, Threshold Consecutive Trading Days (Day)	10 days
Rights Plan [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			1
Preferred Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.001
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 58.00
Share Repurchase Program Authorized November 2022 [Member]
Stock Repurchase Program, Authorized Amount				$ 1,000,000.0
Treasury Stock, Common, Shares (in shares)		5,821
Treasury Stock, Common, Value		$ 69,070
Series D Preferred Stock [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001
Preferred Stock, Shares Issued (in shares)		280,898

[1] The balance sheet at June 30, 2022, has been derived from the audited consolidated financial statements at that date but does not include all of the information and footnotes required by the United States generally accepted accounting principles for complete financial statements.