Note 5 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Unrecognized Tax Benefits	$ 536,000	$ 683,000
Unrecognized Tax Benefits, Decrease Resulting from Current Period Tax Positions	147,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	349,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense	$ 59,000	$ 91,000