Note 2 - Revenue - Net Sales by Product and Service (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net sales	$ 16,404	$ 23,428	$ 31,352	$ 42,756
Less: sales returns	(250)	(417)	(397)	(1,112)
Product [Member]
Net sales	15,200	22,100	29,211	40,623
Freight and Other [Member]
Net sales	$ 1,454	$ 1,745	$ 2,538	$ 3,245