Note 9 - Warrants (Details Textual) - $ / shares	Apr. 28, 2022	Mar. 31, 2023	Dec. 31, 2022	Jun. 30, 2022
Common Stock, Par or Stated Value Per Share (in dollars per share)		$ 0.001	$ 0.001
Prefunded Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	178,847
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 52.00			$ 4
Accompanying Warrant [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)	403,846
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 51.996
Accompanying Warrants with Securities Purchase Agreement [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)	$ 52.40
Warrants and Rights Outstanding, Term (Year)	5 years
Securities Purchase Agreement [Member]
Stock Issued During Period, Shares, New Issues (in shares)	225,000
Common Stock, Par or Stated Value Per Share (in dollars per share)	$ 0.001