Note 6 - Leases - Lease Cost (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Weighted-average remaining lease term (Year)	5 years 8 months 4 days		5 years 8 months 4 days
Weighted-average discount rate	6.06%		6.06%
Operating lease cost	$ 458,838	$ 444,333	$ 910,993	$ 701,215
Cash paid for amounts included in the measurement of lease liabilities	$ 445,310	$ 380,046	$ 849,458	$ 626,781