Note 1 - Description of Business and Basis of Presentation (Details Textual) - USD ($)				9 Months Ended
	Feb. 08, 2021	Feb. 04, 2021	Jan. 28, 2021	Sep. 30, 2021	Nov. 09, 2021	Nov. 04, 2021
Subsequent Event [Member]
Equity Offering Sales Agreement, Aggregate Sales Price Value					$ 50,000,000.0
Common Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares)				2,530,000
The 2021 Offering [Member] | Lake Street Capital Markets, LLC and Northland Securities, Inc. [Member]
Proceeds from Issuance of Common Stock, Net	$ 27,600,000
The 2021 Offering [Member] | Lake Street Capital Markets, LLC and Northland Securities, Inc. [Member] | Common Stock [Member]
Stock Issued During Period, Shares, New Issues (in shares)		2,530,000
Revolving Credit Facility [Member]
Debt Instrument, Collateral Amount			$ 750,000	$ 1,500,000
Line of Credit Facility, Commitment Fee Percentage			5.00%
Revolving Credit Facility [Member] | Subsequent Event [Member]
Debt Instrument, Collateral Amount						$ 3,000,000