Note 7 - Convertible Promissory Note (Details Textual) - USD ($)		12 Months Ended
Jul. 23, 2019	Dec. 31, 2021	Dec. 31, 2020
Amortization of Debt Discount (Premium)		$ 3,631,000	$ 5,558,000
Convertible Debt [Member] \| The July 2019 Note [Member]
Debt Instrument, Face Amount	$ 1,000,000	$ 1,000,000	$ 1,000,000
Debt Instrument, Convertible, Conversion Price (in dollars per share)		$ 1.80	$ 1.80
Debt Instrument, Convertible, Threshold Percentage of Stock Price Trigger	90.00%
Debt Instrument, Interest Rate, Stated Percentage	24.00%	24.00%	24.00%
Amortization of Debt Discount (Premium)		$ 321,000	$ 187,000
Interest Expense, Debt, Total		$ 240,000	$ 240,000
Convertible Debt [Member] \| The July 2019 Note [Member] \| Maximum [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)	$ 1.80
Convertible Debt [Member] \| The July 2019 Note [Member] \| Minimum [Member]
Debt Instrument, Convertible, Conversion Price (in dollars per share)	$ 0.50

Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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The price per share of the conversion feature embedded in the debt instrument.

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