Note 13 - Segment Reporting - Summary of Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019
Balance at beginning of period	$ 131	$ 132
Charged to costs and expenses	64	(1)
Write-offs during period
Balance at end of period	$ 195	$ 131