Note 2 - Summary of Significant Accounting Policies - Stock Options, Valuation Assumptions (Details)	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Non Plan [Member]
Risk free interest rate	0.88%
Expected volatility	131.00%
Life in years (Year)	10 years	10 years
Non Plan [Member] \| Minimum [Member]
Risk free interest rate		1.68%
Expected volatility		133.00%
Non Plan [Member] \| Maximum [Member]
Risk free interest rate		2.65%
Expected volatility		152.00%
2018 Equity Incentive Plan [Member]
Life in years (Year)	10 years	10 years
2018 Equity Incentive Plan [Member] \| Minimum [Member]
Risk free interest rate	0.88%	1.68%
Expected volatility	131.00%	133.00%
Life in years (Year)
2018 Equity Incentive Plan [Member] \| Maximum [Member]
Risk free interest rate	1.90%	2.65%
Expected volatility	133.00%	152.00%

The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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- Definition

The risk-free interest rate assumption that is used in valuing an option on its own shares.

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- Definition

Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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-Publisher FASB
-Name Accounting Standards Codification
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