Note 2 - Revenue - Disaggregation of Revenue by Product Group (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net sales	$ 124,479	$ 146,489	$ 377,284	$ 405,451
Sales Channel, Directly to Consumer [Member]
Net sales	91,344	108,951	274,007	293,416
Sales Channel, Through Intermediary [Member]
Net sales	33,135	37,538	103,277	112,035
North America [Member]
Net sales	65,778	70,654	197,430	201,351
North America [Member] | Sales Channel, Directly to Consumer [Member]
Net sales	44,110	46,802	133,432	128,754
North America [Member] | Sales Channel, Through Intermediary [Member]
Net sales	21,668	23,852	63,998	72,597
Asia [Member]
Net sales	39,954	53,528	116,555	138,062
Asia [Member] | Sales Channel, Directly to Consumer [Member]
Net sales	34,837	46,965	98,672	119,294
Asia [Member] | Sales Channel, Through Intermediary [Member]
Net sales	5,117	6,563	17,883	18,768
Europe [Member]
Net sales	18,747	22,307	63,299	66,038
Europe [Member] | Sales Channel, Directly to Consumer [Member]
Net sales	12,397	15,184	41,903	45,368
Europe [Member] | Sales Channel, Through Intermediary [Member]
Net sales	6,350	7,123	21,396	20,670
Connectivity Solutions [Member]
Net sales	44,531	48,526	131,354	140,373
Connectivity Solutions [Member] | North America [Member]
Net sales	33,929	34,919	97,273	100,797
Connectivity Solutions [Member] | Asia [Member]
Net sales	2,510	5,293	9,012	13,533
Connectivity Solutions [Member] | Europe [Member]
Net sales	8,092	8,314	25,069	26,043
Magnetic Solutions [Member]
Net sales	39,659	52,972	118,605	136,748
Magnetic Solutions [Member] | North America [Member]
Net sales	8,241	10,586	26,662	28,795
Magnetic Solutions [Member] | Asia [Member]
Net sales	29,576	40,100	85,834	100,769
Magnetic Solutions [Member] | Europe [Member]
Net sales	1,842	2,286	6,109	7,184
Power Solutions and Protection [Member]
Net sales	40,289	44,991	127,325	128,330
Power Solutions and Protection [Member] | North America [Member]
Net sales	23,608	25,149	73,495	71,759
Power Solutions and Protection [Member] | Asia [Member]
Net sales	7,868	8,135	21,709	23,760
Power Solutions and Protection [Member] | Europe [Member]
Net sales	$ 8,813	$ 11,707	$ 32,121	$ 32,811