CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 27, 2014	Sep. 28, 2013	Sep. 27, 2014	Sep. 28, 2013
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 4,843	$ 3,347	$ 5,249	$ (21,941)
Other comprehensive income (loss):
Reclassification of realized gain on auction rate securities	0	0	0	(166)
Unrealized gain (loss) on all other available-for-sale investments	(90)	44	(27)	(64)
Foreign currency translation adjustment	(473)	(98)	(142)	(1,016)
Tax related to available-for-sale investment	20	0	0	0
Net change in accumulated other comprehensive income (loss)	(543)	(54)	(169)	(1,246)
Comprehensive income (loss)	$ 4,300	$ 3,293	$ 5,080	$ (23,187)