Note 13 - Employee Equity Incentive Plans - Stock Options Outstanding (Details) - $ / shares	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Low price range (in dollars per share)	$ 0	$ 0
High price range (in dollars per share)	$ 0.50	$ 0.50
Outstanding stock options (in shares)	5,275,000	1,225,000
Weighted average remaining contractual life - outstanding (Year)	4 years 32 days	2 years 226 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.26	$ 0.17
Vested stock options (in shares)	400,000	737,500
Weighted average remaining contractual life - vested (Year)	1 year 153 days	1 year 138 days
Weighted average outstanding strike price - vested (in dollars per share)	$ 0.19	$ 0.15
Range One [Member]
Low price range (in dollars per share)	0	0
High price range (in dollars per share)	$ 0.20	$ 0.20
Outstanding stock options (in shares)	300,000	850,000
Weighted average remaining contractual life - outstanding (Year)	1 year 339 days	2 years 54 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.18	$ 0.15
Vested stock options (in shares)	250,000	625,000
Weighted average remaining contractual life - vested (Year)	1 year 175 days	1 year 116 days
Weighted average outstanding strike price - vested (in dollars per share)	$ 0.17	$ 0.14
Range Two [Member]
Low price range (in dollars per share)	0.21	0.21
High price range (in dollars per share)	$ 0.30	$ 0.30
Outstanding stock options (in shares)	4,250,000	375,000
Weighted average remaining contractual life - outstanding (Year)	4 years 43 days	3 years 255 days
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.25	$ 0.23
Vested stock options (in shares)	150,000	112,500
Weighted average remaining contractual life - vested (Year)	1 year 109 days	1 year 244 days
Weighted average outstanding strike price - vested (in dollars per share)	$ 0.22	$ 0.21
Range Three [Member]
Low price range (in dollars per share)	0.31	0.31
High price range (in dollars per share)	$ 0.50	$ 0.50
Outstanding stock options (in shares)	725,000	0
Weighted average remaining contractual life - outstanding (Year)	4 years 299 days	0 years
Weighted average outstanding strike price - outstanding (in dollars per share)	$ 0.34	$ 0
Vested stock options (in shares)	0	0
Weighted average remaining contractual life - vested (Year)	0 years	0 years
Weighted average outstanding strike price - vested (in dollars per share)	$ 0	$ 0

Weighted-average exercise price, at which grantee can acquire shares reserved for issuance, for fully vested and expected to vest exercisable or convertible options. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (e)(2)
-URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901

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Number of fully vested and expected to vest options outstanding that can be converted into shares under option plan. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
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The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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Weighted average remaining contractual term for fully vested and expected to vest options outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, unvested options for which requisite service period has not been rendered but that are expected to vest based on achievement of performance condition, if forfeitures are recognized when they occur.

+ References

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The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

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-Publisher FASB
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Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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