Note 8 - Stockholders' Equity (Details Textual)	Dec. 19, 2022 $ / shares	Dec. 05, 2022 $ / shares shares	Jun. 30, 2023 USD ($) $ / shares shares	Dec. 21, 2022 $ / shares shares	Nov. 09, 2022 USD ($)	Jun. 30, 2022 USD ($) $ / shares shares	Jun. 30, 2021 $ / shares
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001	$ 0.001			$ 0.001
Preferred Stock, Shares Issued (in shares) | shares			280,898			280,898
Treasury Stock, Common, Shares (in shares) | shares			10,316			0
Treasury Stock, Common, Value | $			$ 119,000			$ (0)
Preferred Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.001			$ 0.001
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)			$ 72.10			$ 72.10	$ 72.10
Stock Issued During Period, Shares, Reverse Stock Splits (in shares) | shares		0
Equity Securities, Minimum Closing Bid Price (in dollars per share)	$ 1.00
Equity Securities, Threshold Consecutive Trading Days (Day)	10 days
Reverse Stock Split [Member]
Stockholders' Equity Note, Stock Split, Conversion Ratio		30
Rights Plan [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares) | 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) | shares			10,316
Treasury Stock, Common, Value | $			$ 118,532
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) | shares			280,898