Note 5 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2023	Jun. 30, 2023	Dec. 21, 2022	Nov. 09, 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
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)	72.1	$ 72.1
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
Share Repurchase Program Authorized November 2022 [Member]
Stock Repurchase Program, Authorized Amount				$ 1
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