Note 11 - Retirement Savings Plans (Details Textual) - USD ($)	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	100.00%	100.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	4.00%	4.00%
Defined Contribution Plan, Employer Contribution Amount	$ 51,647	$ 29,952
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 0	$ 0

Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration