Note 17 - Segment Data - Net Sales by Market (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
Percentage of concentration risk									100.00%	100.00%	100.00%
Medical [Member]
Net sales									$ 120,206	$ 128,915	$ 110,282
Percentage of concentration risk									67.00%	65.00%	57.90%
Consumer [Member]
Net sales									$ 18,263	$ 17,669	$ 24,989
Percentage of concentration risk									10.20%	8.90%	13.10%
Automotive [Member]
Net sales									$ 14,607	$ 20,004	$ 20,022
Percentage of concentration risk									8.10%	10.10%	10.50%
Aerospace & Defense [Member]
Net sales									$ 12,624	$ 13,778	$ 13,130
Percentage of concentration risk									7.00%	6.90%	6.90%
Industrial [Member]
Net sales									$ 7,601	$ 9,607	$ 10,579
Percentage of concentration risk									4.20%	4.80%	5.60%
Electronics [Member]
Net sales									$ 6,072	$ 8,408	$ 11,453
Percentage of concentration risk									3.40%	4.20%	6.00%