Note 2 - Revenue Recognition - Revenue Disaggregated by the Major Types of Goods and Services Sold (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net sales	$ 45,153	$ 43,299	$ 42,644	$ 48,277	$ 50,260	$ 49,394	$ 51,399	$ 47,328	$ 179,373	$ 198,381	$ 190,455
Product [Member]
Net sales									172,299	193,016	183,186
Tooling and Machinery [Member]
Net sales									2,787	2,730	4,302
Engineering and Development [Member]
Net sales									$ 4,287	$ 2,635	$ 2,967