Stockholders' Equity - Components of Accumulated Other Comprehensive Loss (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jul. 01, 2016	Jun. 30, 2017	Jul. 01, 2016	Dec. 31, 2016
Equity [Abstract]
Foreign currency translation adjustments	$ (2,384)		$ (2,384)		$ (7,267)
Unrealized gain on investments	(339)		(339)		276
Actuarial Loss	(279)		(279)		(279)
Accumulated Other Comprehensive Loss	(3,002)		(3,002)		$ (7,270)
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, before Tax	3,994	$ (2,611)	4,883	$ (677)
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Tax	$ (114)	$ (49)	(613)	$ 30
Other Comprehensive Income (Loss), before Reclassifications, before Tax			4,270
Other Comprehensive Income (Loss), Foreign Currency Translation Gain (Loss) Arising During Period, Tax			0
Other Comprehensive Income (Loss), Available-for-sale Securities, Tax			(2)
Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent			$ (2)