Document and Entity Information - USD ($) $ in Billions	12 Months Ended
Document and Entity Information - USD ($) $ in Billions	Jan. 03, 2026	Jan. 31, 2026	Jun. 28, 2025
Document and Entity Information [Abstract]
Document Type	10-K/A
Document Annual Report	true
Document Period End Date	Jan. 03, 2026
Current Fiscal Year End Date	--01-03
Document Fiscal Year Focus	2026
Document Transition Report	false
Entity File Number	001-33642
Entity Registrant Name	MASIMO CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	33-0368882
Entity Address, Address Line One	52 Discovery
Entity Address, City or Town	Irvine
Entity Address State Or Province	CA
Entity Address, Postal Zip Code	92618
City Area Code	949
Local Phone Number	297-7000
Title of 12(b) Security	Common Stock, par value $0.001
Trading Symbol	MASI
Security Exchange Name	NASDAQ
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
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 3.9
Entity Common Stock, Shares Outstanding		52,192,538
Entity Central Index Key	0000937556
Document Fiscal Period Focus	FY
Amendment Flag	false
Auditor Name	GRANT THORNTON LLP
Auditor Location	Newport Beach, California
Auditor Firm ID	248

Award Timing Disclosure	12 Months Ended
Award Timing Disclosure	Jan. 03, 2026
Award Timing Disclosures [Line Items]
Award Timing MNPI Disclosure	The Compensation Committee approves equity awards for our NEOs on or before the effective date of grant, and it is the Compensation Committee’s general practice to approve annual equity awards in the first quarter of each fiscal year. On occasion, equity awards may be granted outside of our annual grant cycle for new hires, promotions, retention, or other purposes. Generally, the effective date of grant for equity awarded to our NEOs is during an open quarterly window period under our Insider Trading Policy or when the Company otherwise has no material non-public information. The Company also does not permit the timed disclosure of material non-public information for the purpose of affecting the value of executive compensation. Equity awards to newly hired employees are effective as of the later of the date the individual commences service or the grant approval date, and equity awards to existing employees and others providing services to us are effective as of the grant approval date. In addition, for options, the exercise price may not be less than the closing price of our common stock on the effective date of the grant.
Award Timing Method	The Compensation Committee approves equity awards for our NEOs on or before the effective date of grant, and it is the Compensation Committee’s general practice to approve annual equity awards in the first quarter of each fiscal year. On occasion, equity awards may be granted outside of our annual grant cycle for new hires, promotions, retention, or other purposes. Generally, the effective date of grant for equity awarded to our NEOs is during an open quarterly window period under our Insider Trading Policy or when the Company otherwise has no material non-public information.
Award Timing Predetermined	true
Award Timing MNPI Considered	false
Award Timing, How MNPI Considered	The Company also does not permit the timed disclosure of material non-public information for the purpose of affecting the value of executive compensation. Equity awards to newly hired employees are effective as of the later of the date the individual commences service or the grant approval date, and equity awards to existing employees and others providing services to us are effective as of the grant approval date. In addition, for options, the exercise price may not be less than the closing price of our common stock on the effective date of the grant.
MNPI Disclosure Timed for Compensation Value	false

Insider Trading Policies and Procedures	12 Months Ended
Insider Trading Policies and Procedures	Jan. 03, 2026
Insider Trading Policies and Procedures [Line Items]
Insider Trading Policies and Procedures Adopted	true