CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 1,148	$ 3,581
Other comprehensive income (loss), before tax
Change in unrealized net loss on available-for-sale investments	70	18
Foreign currency translation gains and (losses)	(24)	(130)
Other comprehensive income (loss), before tax	46	(112)
Income tax expense related to items in other comprehensive income (loss)	0	0
Other comprehensive income (loss), net of tax	46	(112)
Comprehensive income	$ 1,194	$ 3,469