Note 5 - Allowance for Doubtful Accounts - Activity in Accounts Receivable Allowance from Operations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Balance at beginning of period	$ 473	$ 127
Bad debt expense	9	227
Write-offs	(229)	(77)
Other adjustments	(206)	196
Balance at end of period	$ 47	$ 473