Note 12 - Equity Instruments (Details Textual) - USD ($)	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Stock Issued During Period, Shares, Employee Benefit Plan	94,684	105,308
Issuance of Stock to Defined Contribution Plan for Employer Matching Contribution	$ 35,980	$ 53,707
Common Stock [Member]
Stock Issued During Period, Shares, Employee Benefit Plan	94,684
Employees [Member] \| Common Stock [Member]
Stock Issued During Period, Shares, Issued for Services	1,118,760	710,353
Stock Issued During Period, Value, Issued for Services	$ 317,000	$ 369,000
Director [Member] \| Common Stock [Member]
Stock Issued During Period, Shares, Issued for Services	0	16,406
Stock Issued During Period, Value, Issued for Services		$ 10,500