Note 12 - Segment Information - Revenues and Long-lived Assets by Geographical Area (Details) - USD ($) $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 30, 2017		Sep. 30, 2017	[2]	Jul. 01, 2017	[3]	Apr. 01, 2017	[4]	Dec. 31, 2016		Oct. 01, 2016	[6]	Jul. 02, 2016	[7]	Apr. 02, 2016	[8]	Dec. 30, 2017	Dec. 31, 2016	Jan. 02, 2016
Net sales	$ 304,849	[1]	$ 317,889		$ 313,355		$ 285,441		$ 284,518	[5]	$ 280,331		$ 271,912		$ 219,398		$ 1,221,534	$ 1,056,159	$ 867,864
Long-lived assets	250,577								217,175								250,577	217,175	162,568
Additions to long-lived assets																	65,925	46,228	44,019
UNITED STATES
Net sales																	383,025	356,674	344,305
Long-lived assets	23,490								23,731								23,490	23,731	23,965
Additions to long-lived assets																	3,518	4,694	8,609
CHINA
Net sales																	321,111	263,701	193,792
Long-lived assets	86,310								65,345								86,310	65,345	37,241
Additions to long-lived assets																	32,775	13,181	9,710
Other Countries [Member]
Net sales																	517,398	435,784	329,767
Long-lived assets	47,138								42,492								47,138	42,492	20,707
Additions to long-lived assets																	7,258	7,590	3,887
MEXICO
Long-lived assets	62,510								52,262								62,510	52,262	47,130
Additions to long-lived assets																	19,395	15,667	9,193
PHILIPPINES
Long-lived assets	$ 31,129								$ 33,345								31,129	33,345	33,525
Additions to long-lived assets																	$ 2,979	$ 5,096	$ 12,620

[1] In the fourth quarter of 2017, the Company recorded an estimated one-time tax charge of $49 million for the enactment of the Tax Cuts and Jobs Act for deemed repatriation of unremitted earnings of foreign subsidiaries, $1.4 million in acquisition and integration costs and $0.7 million in restructuring and production costs related to the transfer of Asian operations.

[2] In the third quarter of 2017, the Company recorded $4.8 million in acquisition and integration costs and $1.5 million in restructuring and production costs related to the transfer of Asian operations.

[3] In the second quarter of 2017, the Company recorded $0.3 million in acquisition and integration costs.

[4] In the first quarter of 2017, the Company $1.5 million in acquisition and integration costs

[5] In the fourth quarter of 2016, the Company recorded ($0.1) million gain related to the Company's transfer of its reed sensor manufacturing operations from the U.S. and China to the Philippines, $1.2 million of restructuring costs, $3.2 million in acquisition and integration costs and $0.3 million in non-cash inventory charges related to the 2016 acquisitions.

[6] In the third quarter of 2016, the Company recorded $0.9 million of restructuring costs, $5.9 million in acquisition and integration costs, $14.8 million of charges related to the impairment of the Custom Products reporting unit and $0.5 million in non-cash inventory charges as noted above.

[7] In the second quarter of 2016, the Company recorded $0.7 million related to the reed sensor manufacturing transfer as noted above, $0.1 million of restructuring costs, $6.1 million in acquisition and integration costs, $0.3 million in charges related to the closure of the manufacturing facility in Denmark and $6.9 million in non-cash inventory charges as noted above.

[8] In the first quarter of 2016, the Company recorded $1.0 million related to the reed sensor manufacturing transfer as noted above, $0.4 million of restructuring costs, $6.2 million in acquisition and integration costs, and $1.6 million in charges related to the closure of the manufacturing facility in Denmark.