Note 9 - Retirement Plans (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	25.00%	25.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%	6.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0	$ 0
Defined Contribution Plan, Cost	$ 32,162	$ 30,599