Income Taxes (Details 5) - USD ($) $ in Thousands		12 Months Ended
		Jan. 02, 2021	Dec. 28, 2019	Dec. 29, 2018
Unrecognized Tax Benefits
Unrecognized tax benefits at the beginning of the fiscal year		$ 106,041	$ 101,857	$ 110,179
Gross amount of the decreases in unrecognized tax benefits of tax positions taken during a prior year	[1]		(3,143)	(4,183)
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	[1]	5,037
Gross amount of the increases in unrecognized tax benefits as a result of tax positions taken during the current year		3,344	8,951	2,370
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities		(1,316)	(380)	0
Reductions to unrecognized tax benefits resulting from the lapse of the applicable statute of limitations		(676)	(1,692)	(5,179)
Unrecognized Tax Benefits, Increase Resulting from Foreign Currency Translation		591	448
Decrease resulting from foreign currency translation				(1,330)
Unrecognized tax benefits at the end of the fiscal year		113,021	106,041	101,857
Total amounts of unrecognized tax benefits that, if upon resolution of the uncertain tax positions would reduce Cadence's effective tax rate		66,010	61,527	58,022
Interest and penalties recognized in Income Statements
Interest		473	490	585
Penalties		(3)	19	$ 342
Interest and penalties recognized in Balance Sheets
Interest		3,555	3,500
Penalties		$ 12	$ 12

[1] Includes unrecognized tax benefits of tax positions recorded in connection with acquisitions