Note 4 - Liquidity and Business Plan (Details Textual) - USD ($) $ / shares in Units, $ in Thousands			2 Months Ended	3 Months Ended	9 Months Ended
	Jul. 02, 2021	Sep. 01, 2020	Mar. 23, 2021	Jun. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Proceeds from Issuance of Common Stock, Net					$ 9,053
Stock Issued During Period, Shares, Exercise of Warrants for Cash (in shares)			228,938		228,939
Proceeds from Warrant Exercises			$ 1,000		$ 1,042	$ 52
Proceeds from Issuance of Private Placement						1,746
Underwritten Public Offering [Member]
Stock Issued During Period, Shares, New Issues (in shares)	3,333,334	2,545,454
Shares Issued, Price Per Share (in dollars per share)	$ 3.00
Proceeds from Issuance of Common Stock, Net	$ 9,100
Proceeds from Issuance of Common Stock, Net		$ 9,300				$ 9,335
Private Placement [Member]
Proceeds from Issuance of Private Placement				$ 1,700