CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 30, 2019	Jun. 27, 2020	Jun. 30, 2019
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 7,424	$ 5,526	$ 3,020	$ 13,102
Other comprehensive income (loss), net of tax:
Change in net unrealized gains on available-for-sale marketable securities	795	114	269	209
Change in currency translation adjustments	2,495	316	264	(202)
Other comprehensive income	3,290	430	533	7
Total comprehensive income	$ 10,714	$ 5,956	$ 3,553	$ 13,109