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, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for doubtful accounts
Balance at Beginning of Period	$ 299	$ 381	$ 354
Charged to Costs and Expenses			27
Deductions/ Write-offs of Accounts	99	82
Balance at End of Period	$ 200	$ 299	$ 381