Income Taxes - Unrecognized tax benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 01, 2022	Jan. 02, 2021	Dec. 28, 2019
Summary of the activity related to gross unrecognized tax benefits
Beginning balance	$ 2,853	$ 2,276	$ 2,036
Additions based on tax positions related to current year	830	577	436
Reductions based on tax positions related to prior years	(6)		(196)
Ending balance	3,677	2,853	2,276
Unrecognized tax benefits, other disclosures
Gross unrecognized tax benefits, inclusive of interest	3,900	3,000	2,400
Gross unrecognized tax benefits which would affect the effective tax rate if recognized	$ 3,900	$ 2,100	$ 1,900