Note 2 - Restricted Cash - Cash and Cash-restricted (Details) - USD ($)	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Dec. 31, 2016
Cash	$ 1,992,461		$ 1,618,583
Restricted cash		$ 873,355	33,821
Total	$ 1,992,461		$ 1,652,404	$ 1,102,466	$ 1,081,188

Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Period Type:	instant