Note 1 - Summary of Significant Accounting Policies - Allowance for Doubtful Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance	$ 175	$ 200	$ 169
Bad Debt Expense	75	80	249
Write-offs Net of Recoveries	106	105	218
Balance	$ 144	$ 175	$ 200