Note 4 - Income Taxes (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount	$ 3,000,000
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	80,000	$ 97,000
Liability for Uncertainty in Income Taxes, Current	358,000	$ 307,000
Domestic Tax Authority [Member]
Operating Loss Carryforwards	29,200,000
State and Local Jurisdiction [Member]
Operating Loss Carryforwards	$ 22,300,000