Document and Entity Information	6 Months Ended
	Jun. 29, 2019 shares
Cover page.
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	CDNS
Document Transition Report	false
Document Quarterly Report	true
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	00-0000000
Entity Address, Address Line One	2655 Seely Avenue, Building 5,
Entity Address, City or Town	San Jose,
Entity Address, State or Province	CA
Entity Registrant Name	CADENCE DESIGN SYSTEMS INC
City Area Code	(408)
Local Phone Number	943-1234
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Central Index Key	0000813672
Document Type	10-Q
Document Period End Date	Jun. 29, 2019
Entity File Number	000-15867
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-28
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding	280,153,000
Entity Address, Postal Zip Code	95134
Security Exchange Name	NASDAQ