Segment Information (Details) $ in Thousands	12 Months Ended
	Dec. 29, 2018 USD ($) segment product	Dec. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Information
Number of operating segments | segment	1
Number of product categories | product	4
Revenues	$ 868,267	$ 768,867	$ 697,626
Property and equipment, net	139,049	127,682
United States
Segment Information
Revenues	149,385	112,574	94,583
Property and equipment, net	128,622	119,746
China
Segment Information
Revenues	344,255	307,748	291,974
Rest of world
Segment Information
Revenues	374,627	348,545	$ 311,069
Property and equipment, net	$ 10,427	$ 7,936