Note 10 - Business Unit Segment Information - Net Sales by Geographic Area (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 27, 2015	Jun. 28, 2014	Jun. 27, 2015	Jun. 28, 2014
UNITED STATES
Net Sales	[1]	$ 89,608	$ 80,492	$ 172,981	$ 152,366
CHINA
Net Sales	[1]	49,920	39,987	94,349	77,200
Other Countries [Member]
Net Sales	[1]	82,493	100,429	165,004	198,201
Net Sales	[1]	$ 222,021	$ 220,908	$ 432,334	$ 427,767

[1] Sales by country represent sales to customer or distributor locations.