Note 10 - Notes Payable with Hercules Credit Agreement (Details) - Hercules Credit Agreement [Member] - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Principal amount	$ 5,363,798	$ 6,345,769
Amortized end of term charges	290,257	265,859
Unamortized debt issuance costs	(133,622)	(187,894)
Total convertible notes payable	$ 5,520,433	$ 6,423,734

Amount of accumulated amortization of debt issuance costs.

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-Name Accounting Standards Codification
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-SubTopic 30
-Section 45
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Face (par) amount of debt instrument at time of issuance.

+ References

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-SubTopic 30
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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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