Note 17 - 401(k) Savings Plan (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan, Employee Eligible Service Period (Month)	30 days
Defined Benefit Plan, Eligible Age for Employee (Year)	21 years
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	50.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	6.00%
Defined Contribution Plan, Employee Eligible Service Period for Employer Match (Month)	180 days
Defined Contribution Plan, Cost	$ 251,000	$ 204,000	$ 173,000