Note 6 - Mezzanine Equity (Details Textual) - USD ($)				3 Months Ended				9 Months Ended
	Dec. 31, 2020	Dec. 23, 2020	Nov. 12, 2020	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 18, 2018
Amortization of Debt Issuance Costs and Discounts, Total							$ 170,000		$ 517,000
Stock Issued During Period, Shares, New Issues (in shares)								1,000,000
Liabilities Exchanged for Stock			$ 661,000
Conversion of Preferred Series C Stock to Preferred Series D Stock [Member]
Conversion of Stock, Shares Issued (in shares)			10,000
Conversion of Stock, Shares Converted (in shares)			1,000
Conversion of Series D Preferred Stock to Common Stock [Member]
Conversion of Stock, Shares Issued (in shares)								11,149,123
Conversion of Stock, Shares Converted (in shares)								646
Conversion of Series D Preferred Stock to Common Stock Issued for Dividends [Member]
Conversion of Stock, Shares Issued (in shares)								70,221
Bridge Note [Member]
Proceeds from Issuance of Debt			$ 2,200,000
Series C Preferred Stock [Member]
Temporary Equity, Shares Authorized (in shares)										1,000
Temporary Equity, Par or Stated Value Per Share (in dollars per share)										$ 0.01
Temporary Equity, Liquidation Preference Per Share (in dollars per share)										$ 10,000
Preferred Stock, Discount on Shares										$ 833,000
Series D Preferred Stock [Member]
Preferred Stock, Discount on Shares	$ 21,291,000			$ 15,992,000				$ 15,992,000
Preferred Stock, Dividend Rate, Percentage			4.00%
Preferred Stock, Convertible, Conversion Price (in dollars per share)			$ 0.0583
Stock Issued During Period, Shares, New Issues (in shares)		500	11,560
Proceeds from Issuance or Sale of Equity, Total		$ 500,000	$ 11,560,000
Shares Issued, Price Per Share (in dollars per share)			$ 1,000
Liabilities Exchanged for Stock, Shares (in shares)			6,613
Conversion of Stock, Shares Issued (in shares)				249	251	248
Conversion of Stock, Shares Converted (in shares)				242	50	354
Preferred Stock Dividends, Shares (in shares)	142							748
Embedded Derivative, Fair Value of Embedded Derivative Liability				$ 26,011,000				$ 26,011,000
Accretion Expense				1,665,000				5,214,000
Preferred Stock, Value, Issued, Ending Balance	$ 1,572,000			$ 6,973,000				$ 6,973,000