Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 17,675	$ 8,288	$ 34,056	$ 13,640
Other comprehensive income:
Change in foreign currency translation adjustment	(2,555)	761	(568)	2,706
Net change in unrealized gains (losses) on available-for-sale investments	52	(8)	(37)	(17)
Other comprehensive income (loss):	(2,503)	753	(605)	2,689
Comprehensive income	$ 15,172	$ 9,041	$ 33,451	$ 16,329

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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