Note 8 - Convertible Notes Payable - Convertible Debt Maturity Payments (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Total	$ 5,970,000	$ 6,170,000
Convertible Debt [Member]
2019	0
2020	5,770,000
2021	200,000
Total	$ 5,970,000

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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