Note 7 - Stockholders' Equity (Details Textual) - USD ($)		3 Months Ended	9 Months Ended
	Mar. 15, 2023	Sep. 30, 2023	Sep. 30, 2023	Sep. 30, 2022	Dec. 31, 2022	Mar. 31, 2022	Feb. 03, 2022
Stock Issued During Period, Shares, New Issues	125,000
Common Stock, Par or Stated Value Per Share	$ 0.001	$ 0.001	$ 0.001		$ 0.001
Class of Warrant or Right, Outstanding		1,238,869	1,238,869		340,689
Class of Warrant or Right, Exercise Price of Warrants or Rights		$ 3.14	$ 3.14		$ 19.40
Warrants and Rights Outstanding, Term		4 years 9 months 25 days	4 years 9 months 25 days		1 year 10 months 24 days
Proceeds from Issuance or Sale of Equity	$ 2,640,000,000,000
Payments of Stock Issuance Costs	$ 360,000,000
Warrants Exercised			158,731
Proceeds from Warrant Exercises			$ 421,000
Proceeds from Issuance of Common Stock, Net			$ 2,640,000	$ 3,037,000
Warrant Amendment Agreement [Member]
Stock Issued During Period, Shares, New Issues	158,731
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 6.30	$ 2.65	$ 2.65
Warrants Exercised			158,731
Proceeds from Warrant Exercises			$ 421,000
At The Market Offering Agreement [Member]
Stock Issued During Period, Shares, New Issues			196,843
Payments of Stock Issuance Costs			$ 256,000
Maximum Offering Price for Issuance of Common Stock						$ 18,573,000
Additional Common Stock, Shares Authorized							$ 4,275,000
Proceeds from Issuance of Common Stock			$ 3,293,000
Shares Issued, Average Price Per Share			$ 16.55
Proceeds from Issuance of Common Stock, Net			$ 3,037,000
At The Market Offering Agreement [Member] | Minimum [Member]
Maximum Offering Price for Issuance of Common Stock							15,280,000
At The Market Offering Agreement [Member] | Maximum [Member]
Maximum Offering Price for Issuance of Common Stock							$ 19,555,000
Pre-funded Warrant [Member]
Class of Warrant or Right, Outstanding	946,429
Share Price (in dollars per share)	$ 2.80
Class of Warrant or Right, Number of Securities Called by Warrants or Rights	1,071,429
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 2.65
Warrants and Rights Outstanding, Term	5 years 6 months
Warrants Exercised		946,429	946,429
Warrants Issued in Connection with Underwritten Public Offering [Member]
Fair Value Adjustment of Warrants			$ 50,000