Stock-based compensation - Summary of Option, Activity (Details) - $ / shares	12 Months Ended
	Jan. 02, 2022	Jan. 03, 2021	Dec. 29, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Outstanding as of January 3, 2021	16,080,124
Granted	270,119
Canceled	(1,056,687)
Exercised	(2,338,652)		0
Outstanding as of January 2, 2022	12,954,904	16,080,124
Exercisable as of January 2, 2022	7,596,739
Expected to vest as of January 2, 2022	1,823,386
Total vested and expected to vest as of January 2, 2022	9,420,125
Outstanding as of January 3, 2021	$ 9.66
Granted	16.46
Canceled	11.91
Exercised	6.86
Outstanding as of January 2, 2022	10.13	$ 9.66
Exercisable as of January 2, 2022	8.27
Expected to vest as of January 2, 2022	12.65
Total vested and expected to vest as of January 2, 2022	9.12
Outstanding as of January 3, 2021	3.93
Granted	7.04
Canceled	3.71
Excercised	3.88
Outstanding as of January 2, 2022	4.02	$ 3.93
Exercisable as of January 2, 2022	3.85
Expected to vest as of January 2, 2022	5.20
Total vested and expected to vest as of January 2, 2022	$ 4.11
Weighted average remaining contractual term	3 years 1 month 24 days	3 years 6 months 21 days
Exercisable as of January 2, 2022	2 years 6 months 3 days
Expected to vest as of January 2, 2022	4 years 3 days
Total vested and expected to vest as of January 2, 2022	2 years 9 months 18 days