Note 6 - Accounting for Stock-based Compensation (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross	0	0	24,000	24,000
Allocated Share-based Compensation Expense	$ 6,000	$ 20,000	$ 16,000	$ 82,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	0	0	50,000	136,000