Note 12 - Concentration of Credit Risk (Details Textual) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Cash, Uninsured Amount	$ 10,052,914	$ 6,967,469

The amount of cash as of the balance sheet date that is not insured by the Federal Deposit Insurance Corporation.

No definition available.

Name:	us-gaap_CashUninsuredAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant