Note 1 - Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018		Dec. 31, 2017
Balance at Beginning of Period	$ 54		$ 61
Charged to Costs and Expenses	8		3
Charged to Other Accounts
Deductions	(5)	[1]	(10)
Balance at End of Period	$ 57		$ 54

[1] Uncollectible accounts written off, net of recoveries.