Note 6 - Convertible Promissory Notes - Convertible Promissory Notes (Details) - Convertible Debt [Member] - The July 2019 Note [Member] - USD ($)	3 Months Ended	12 Months Ended
Mar. 31, 2021	Dec. 31, 2020	Jul. 23, 2019
Maturity Date	Jul. 31, 2022	Jul. 31, 2022
Stated Interest Rate	24.00%	24.00%	24.00%
Conversion Price (in dollars per share)	$ 1.80	$ 1.80
Face Value	$ 1,000,000	$ 1,000,000	$ 1,000,000
Remaining debt discount	(428,000)	(507,000)
Carrying Value	$ 572,000	$ 493,000

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

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Amount, after accumulated amortization, of debt discount.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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