Equity - Changes in Accumulated Other Comprehensive Income by Component (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 97,155	$ 95,669	$ 101,556	$ 95,793
Net current-period other comprehensive income (loss)	19	71	(69)	(22)
Ending balance	91,748	97,655	91,748	97,655
Foreign currency
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	534	286	602	381
Other comprehensive income (loss) before reclassification	28	20	(40)	(75)
Net current-period other comprehensive income (loss)	28	20	(40)	(75)
Ending balance	562	306	562	306
Unrealized holding gains (losses) on available- for-sale investments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	18	45	38	43
Other comprehensive income (loss) before reclassification	(9)	51	(29)	53
Net current-period other comprehensive income (loss)	(9)	51	(29)	53
Ending balance	9	96	9	96
Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	552	331	640	424
Other comprehensive income (loss) before reclassification	19	71	(69)	(22)
Net current-period other comprehensive income (loss)	19	71	(69)	(22)
Ending balance	$ 571	$ 402	$ 571	$ 402