Note 1 - Business and Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - Allowance for Doubtful Accounts [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for doubtful accounts
Balance at Beginning of Period	$ 381	$ 354	$ 351
Charged to Costs and Expenses		$ 27	$ 3
Deductions/ Write-offs of Accounts	$ 82
Balance at End of Period	$ 299	$ 381	$ 354