Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 27, 2015	Sep. 28, 2014	Sep. 27, 2015	Sep. 28, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 2,023	$ 537	$ 10,909	$ 4,918
Other comprehensive income (loss)
Changes in foreign currency translation adjustments	(682)	(1,287)	(1,723)	(1,770)
Other comprehensive income (loss)	(682)	(1,287)	(1,723)	(1,770)
Comprehensive income (loss)	$ 1,341	$ (750)	$ 9,186	$ 3,148