Note 3 - Convertible Notes Payable and Lines of Credit - Pricing Supplements (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Aggregate outstanding	$ 675,571	$ 5,250,668
The 2015 Unit Offering [Member]
Warrant exercise price (in dollars per share)
Aggregate outstanding	$ 4,550,097
Conversion price (in dollars per share)
Pricing Supplement No.1 [Member] \| The 2015 Unit Offering [Member]
Warrant exercise price (in dollars per share)	$ 0.40
Aggregate outstanding	$ 1,652,384
Conversion price (in dollars per share)	$ 0.25
Pricing Supplement No.2 [Member] \| The 2015 Unit Offering [Member]
Warrant exercise price (in dollars per share)	$ 0.45
Aggregate outstanding	$ 1,751,046
Conversion price (in dollars per share)	$ 0.35
Pricing Supplement No.3 [Member] \| The 2015 Unit Offering [Member]
Warrant exercise price (in dollars per share)	$ 0.70
Aggregate outstanding	$ 1,146,667
Conversion price (in dollars per share)	$ 0.55

Exercise price per share or per unit of warrants or rights outstanding.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.4-08.(i)(4))
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690

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- Definition

Carrying value as of the balance sheet date of long-term debt (with maturities initially due after one year or beyond the operating cycle if longer) identified as Convertible Notes Payable, excluding current portion. Convertible Notes Payable is a written promise to pay a note which can be exchanged for a specified amount of another, related security, at the option of the issuer and the holder.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 5
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=6928298&loc=SL6031898-161870

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