Note 9 - Segment and Enterprise-wide Disclosures - Net Sales to Unaffiliated Customers by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Net Sales	$ 24,851	$ 29,483	$ 55,402	$ 57,962
UNITED STATES
Net Sales	13,535	16,006	30,535	30,764
GERMANY
Net Sales	2,699	3,192	5,993	6,272
Other Countries [Member]
Net Sales	$ 8,617	$ 10,285	$ 18,874	$ 20,926