Note 6 - Convertible Debt - Outstanding Convertible Notes (Details)	6 Months Ended
Jun. 30, 2017 USD ($) $ / shares
Total principal amount	$ 2,430,000
2016 Convertible Notes [Member]
Maturity Date	Sep. 27, 2017
Conversion Price (in dollars per share) \| $ / shares	$ 3.50
Interest Rate	6.00%
Total principal amount	$ 1,880,000
Issue Date	Sep. 27, 2016
Convertible Note Series B [Member]
Maturity Date	Jun. 30, 2018
Conversion Price (in dollars per share) \| $ / shares	$ 2.74
Interest Rate	1.00%
Total principal amount	$ 550,000
Issue Date	Mar. 15, 2011

Including the current and noncurrent portions, carrying value as of the balance sheet date of a written promise to pay a note, initially due after one year or beyond the operating cycle if longer, which can be exchanged for a specified amount of one or more securities (typically common stock), at the option of the issuer or the holder.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-04(13))
-URI http://asc.fasb.org/extlink&oid=6488278&loc=d3e603758-122996

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section S99
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-Name Accounting Standards Codification
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-Paragraph 1
-Subparagraph (SX 210.5-02(22))
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The price per share of the conversion feature embedded in the debt instrument.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
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Contractual interest rate for funds borrowed, under the debt agreement.

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Date the debt instrument was issued, in CCYY-MM-DD format.

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

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