Note 5 - Assets Held for Rent - Assets Held for Rent (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2021	Dec. 31, 2020
Shippers placed in service	$ 4,750	$ 3,171
Fixed assets held for rent	421	0
Accumulated depreciation	(597)	(411)
Net	4,574	2,760
Shippers and related components in production	1,929	1,945
Total	$ 6,503	$ 4,705