Note 7 - Stockholders' Equity (Details Textual) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended		6 Months Ended		12 Months Ended	67 Months Ended
	Aug. 31, 2020	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021	Jun. 30, 2022	Nov. 30, 2016
Dividends, Preferred Stock, Total		$ 1,283	$ 1,318	$ 2,581	$ 2,622
Preferred Stock, Shares Outstanding, Ending Balance (in shares)		62,000		62,000		80,000	62,000
Conversion From Preferred Stock to Common Stock [Member]
Conversion of Stock, Shares Converted (in shares)				18,000		5,000
Conversion of Stock, Shares Issued (in shares)				2,109,561		566,364
Series A Redeemable Convertible Preferred Stock [Member]
Temporary Equity, Shares Issued (in shares)		62,000		62,000		80,000	62,000
Deferred Offering Costs		$ 2,100		$ 2,100			$ 2,100
Dividends, Preferred Stock, Total		$ 1,300	$ 1,300	$ 2,600	2,600
Preferred Stock, Shares Outstanding, Ending Balance (in shares)		62,000		62,000			62,000
Convertible Preferred Stock, Shares Reserved for Future Issuance (in shares)		7,300,000		7,300,000			7,300,000
Series A Redeemable Convertible Preferred Stock [Member] | Private Placement [Member]
Temporary Equity, Shares Issued (in shares)	85,000
Temporary Equity, Redemption Price Per Share (in dollars per share)	$ 1,000
Proceeds from Issuance of Preferred Stock and Preference Stock	$ 85,000
Preferred Stock, Dividend Rate, Percentage	6.00%
Convertible Preferred Stock, Conversion Price (in dollars per share)	$ 9.50
Common Stock [Member]
Dividends, Preferred Stock, Total				$ (0)	$ (0)
Stock and Warrant Repurchase Plan [Member]
Stock Repurchase Program, Authorized Amount								$ 35,000
Warrants Repurchased During Period (in shares)							6,011,926
Warrants Repurchased During Period, Value							$ 14,700
Stock Repurchase Program, Remaining Authorized Repurchase Amount		$ 12,000		$ 12,000			$ 12,000
Stock and Warrant Repurchase Plan [Member] | Common Stock [Member]
Stock Repurchased During Period, Shares (in shares)							875,218
Stock Repurchased During Period, Value							$ 8,300