Note 2 - Summary of Significant Accounting Policies - Allowance for Doubtful Account Summary (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Beginning of period	$ 179,813	$ 116,834
Bad debt expense	130,346	132,767
Write-offs	(160,179)	(69,788)
End of period	$ 149,980	$ 179,813