Summary of Significant Accounting Policies - New Accounting Standards (Details Textual) - USD ($) $ in Thousands		3 Months Ended		12 Months Ended
		Dec. 29, 2018		Dec. 29, 2018		Dec. 31, 2017	Dec. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ 772,709		$ 772,709		$ 426,932	$ 341,003
Receivables, net		297,082		297,082			190,426
Contract assets		10,055		10,055			3,964
Current portion of deferred revenue		352,456		352,456			336,297
Accounts payable and accrued liabilities		$ 256,526	[1]	$ 256,526	[1]		$ 221,101
Percentage of revenue recognizable over time		90.00%		90.00%
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	[2]					91,640
Cumulative effect adjustment to beginning retained earnings, tax effect	[2]					(17,500)
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings						2,638
Accounting Standards Update 2016-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings						(8,349)
Difference between Revenue Guidance in Effect before and after Topic 606 [Member] | Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ (86,120)		$ (86,120)		85,400
Receivables, net		(12,099)		(12,099)		47,300
Contract assets						4,000
Current portion of deferred revenue		45,119		45,119		57,400
Accounts payable and accrued liabilities		$ (17,438)	[1]	$ (17,438)	[1]	23,300
Deferred sales commissions						$ 27,300

[1] Cadence has certain arrangements under which consideration is received from customers prior to identifying the specific goods or services to be delivered under the contract. Cadence records an accrued liability on a contract-by-contract basis at the end of each reporting period for cash consideration received.

[2] The cumulative effect adjustment from the adoption of Revenue from Contracts with Customers (Topic 606) is presented net of the related income tax effect of $17.5 million.