Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018		Jan. 01, 2019
Asset Impairment Charges, Total	$ 0	$ 0
Cumulative Effect of New Accounting Principle in Period of Adoption
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	370,000	349,750
Share-based Payment Arrangement, Expense	$ 451,000	$ 432,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	35.00%
Advertising Expense	$ 16,000	$ 32,000
Assets, Total	38,091,000	$ 34,255,000	[1]
Accounting Standards Update 2014-09 [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	$ 0
Accounting Standards Update 2018-11 [Member]
Assets, Total				$ 3,455,000
Minimum [Member]
Finite-Lived Intangible Asset, Useful Life	5 years
Maximum [Member]
Finite-Lived Intangible Asset, Useful Life	17 years

[1] The condensed consolidated balance sheet as of December 31, 2018 has been prepared using information from the audited consolidated balance sheet as of that date.