Note 11 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Expense (Benefit), Total	$ (174,000)	$ 225,000	$ (3,505,000)	$ 166,000
Income Tax Benefit for Excess Tax Deductions Related to Employee Share-based Compensation	$ 300,000		$ 2,800,000