Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	12 Months Ended
	Dec. 26, 2015	Dec. 27, 2014	Dec. 28, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ 2,905	$ (31,118)	$ (14,146)
Other comprehensive income (loss):
Change in foreign currency translation adjustment	(2,344)	(3,239)	(818)
Employee benefit plan adjustment	(76)	(106)	151
Net change on unrealized gains (losses) on available-for-sale investments	(13)	(36)	7
Other comprehensive loss	(2,433)	(3,381)	(660)
Comprehensive income (loss)	$ 472	$ (34,499)	$ (14,806)