Note 11 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Expense (Benefit), Total	$ (712,000)	$ 59,000	$ (3,331,000)	$ (59,000)
Income Tax Benefit for Excess Tax Deductions Related to Employee Share-based Compensation	$ 1,140,000		$ 2,600,000