Note 8 - Leases - Supplemental Cash Flow Information Related to Operating and Finance Leases (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Operating cash flows from operating leases	$ 164,752
Operating cash flows from finance leases	32,327	$ 18,646
Financing cash flows from finance leases	182,512	102,764
Right-of-use assets obtained in exchange for lease obligations: Finance leases	$ 1,432,662