Revenue (Details Textual) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jul. 03, 2021	Jun. 27, 2020	Jul. 03, 2021	Jun. 27, 2020
Revenue from Contract with Customer [Abstract]
Revenue recognized from deferred revenue during the period	$ 103.4	$ 88.1	$ 330.0	$ 241.6
Remaining performance obligations	3,900.0		3,900.0
Non-cancellable IP access agreements included in remaining performance obligations	$ 110.0		$ 110.0
Percent of remaining performance obligations, current	55.00%		55.00%
Revenue recognized from satisfaction of performance obligations	$ 11.5	$ 11.3	$ 21.7	$ 20.8

Percent of remaining performance obligation to be recognized in next twelve months.

No definition available.

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- Definition

Amount of transaction price for non-cancellable IP access agreements allocated to performance obligation that has not been recognized as revenue

+ References

No definition available.

+ Details

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Namespace Prefix:	cdns_
Data Type:	xbrli:monetaryItemType
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- Definition

Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130549-203045

+ Details

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Balance Type:	credit
Period Type:	duration

- Definition

Amount of revenue recognized from performance obligation satisfied or partially satisfied in previous reporting periods. Includes, but is not limited to, change in transaction price.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12A
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL108322424-203045

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

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Balance Type:	na
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- Definition

Amount of transaction price allocated to performance obligation that has not been recognized as revenue.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

+ Details

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Period Type:	instant