Note 15 - Employee Benefit Plans (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Contribution Plan Eligibility	90 days
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	3.00%
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 285,618	$ 285,477
Employee Stock Purchase Plan, Percent of Wages Withheld, Maximum	10.00%
Employee Stock Purchase Plan, Max Annual Contribution by Employees	$ 10,000
Percent of Purchase Price to Company's Common Stock on Last Day of Offering Period	85.00%
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 108,466	$ 51,593
Stock Issued During Period, Shares, Employee Stock Purchase Plans	19,641	23,681
Employee Stock Purchase Plan, Shares Authorized	100,000
Employee Stock Purchase Plan, Employer Expense During Period	$ 31,954	$ 28,629