Income Taxes - Tax rate reconciliation (Details)	12 Months Ended
	Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Reconciliation of federal statutory tax rate to effective tax rate
Federal statutory rate (as a percent)	21.00%	21.00%	21.00%
Foreign tax rate benefit (as a percent)	(19.20%)	(14.90%)	(14.80%)
Research and development tax credits (as a percent)	(50.90%)	(15.20%)	(9.80%)
GILTI and Subpart F income	35.70%	4.90%	4.10%
Nondeductible (nontaxable) foreign items	(1.50%)	5.40%	4.40%
State tax expense	2.60%	1.00%	1.50%
Release of prior year unrecognized tax benefits (as a percent)		(0.40%)	(2.70%)
Nondeductible officer compensation	15.70%	4.30%	2.40%
Change in cost-sharing treatment of stock-based compensation		54.80%	(2.20%)
Excess tax benefit of stock-based compensation	(4.00%)	(2.20%)	(5.90%)
Change in prior period valuation allowance	2.50%	1.30%	(2.50%)
One-time impacts of tax reform		(0.50%)	(11.50%)
Nondeductible (nontaxable) domestic items	14.80%	2.80%	1.50%
Other (as a percent)	1.40%	(1.10%)	(1.30%)
Effective Tax Rate (as a percent)	18.10%	61.20%	(15.80%)