Note 14 - Stock Based Compensation - Valuation Assumptions for Liability Options (Details)	12 Months Ended
Dec. 31, 2018 $ / shares
Expected term (in years) (Year)	10 years
Dividend yield	0.00%
Liability Options [Member]
Dividend yield
Liability Options [Member] \| Minimum [Member]
Risk free interest rate	2.51%
Expected term (in years) (Year)	4 years 182 days
Stock price (in dollars per share)	$ 1.02
Expected volatility	122.00%
Liability Options [Member] \| Maximum [Member]
Risk free interest rate	2.94%
Expected term (in years) (Year)	5 years
Stock price (in dollars per share)	$ 2.38
Expected volatility	125.00%

The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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- Definition

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.

+ References

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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

Price of a single share of a number of saleable stocks of a company.

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No definition available.

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- Definition

Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (f)(2)(i)
-URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 14.D.2)
-URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809

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