Note 9 - Convertible Debt - Outstanding Convertible Notes (Details) - USD ($)	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Total principal amount	$ 2,430,000	$ 1,245,000
Less current portion of convertible notes	(1,880,000)	(424,964)
Convertible notes, net of current portion	$ 550,000	818,646
Less: unamortized debt issuance costs		$ (1,390)
2016 Convertible Notes [Member]
Issue Date	Sep. 27, 2016
Maturity Date	Sep. 27, 2017
Conversion Price (in dollars per share)	$ 3.50
Interest Rate	6.00%
Total principal amount	$ 1,880,000
Convertible Note Series B [Member]
Issue Date	Mar. 15, 2011	Mar. 15, 2011
Maturity Date	Jun. 30, 2018	Jun. 30, 2018
Conversion Price (in dollars per share)	$ 2.74	$ 2.74
Interest Rate	1.00%	1.00%
Total principal amount	$ 550,000	$ 570,000
Convertible Note Series C [Member]
Issue Date		Sep. 14, 2012
Maturity Date		Jun. 30, 2018
Conversion Price (in dollars per share)		$ 2.74
Interest Rate		1.00%
Total principal amount		$ 425,000
Convertible Note Series E [Member]
Issue Date		Jun. 30, 2014
Maturity Date		Jun. 30, 2018
Conversion Price (in dollars per share)		$ 4.11
Interest Rate		1.00%
Total principal amount		$ 50,000
Series F Notes [Member]
Issue Date		Dec. 04, 2015
Maturity Date		Dec. 04, 2019
Conversion Price (in dollars per share)		$ 5.48
Interest Rate		1.00%
Total principal amount		$ 200,000

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.

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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.

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

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Contractual interest rate for funds borrowed, under the debt agreement.

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