Document and Entity Information - USD ($)	12 Months Ended
	Jan. 02, 2021	Feb. 06, 2021	Jun. 27, 2020
Cover [Abstract]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Jan. 02, 2021
Document Transition Report	false
Entity File Number	000-15867
Entity Registrant Name	CADENCE DESIGN SYSTEMS, INC.
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 Address, Postal Zip Code	95134
City Area Code	(408)
Local Phone Number	943-1234
Title of 12(b) Security	Common Stock, $0.01 par value per share
Trading Symbol	CDNS
Security Exchange Name	NASDAQ
Entity Central Index Key	0000813672
Amendment Flag	false
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 26,162,000,000
Entity Common Stock, Shares Outstanding		278,974,000
Current Fiscal Year End Date	--01-02