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Concentration Risk, Just-in-time Distributors

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Contingencies And Commitments [Line Items]

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Employment Agreement, Severance Benefits, Special Payment, Qualifying Termination

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Employment Agreement, Severance Terms

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Loss Contingency, Damages Sought, Value Per Violation

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Percentage of the Company's total revenue that is from one customer.

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Percentage of revenue two customer.

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Percentage of Accounts Receivable Balance

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Percentage of Revenue - Customer Concentration

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- Definition

Severance plan participation agreements.

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Supplemental Unemployment Benefits, Severance Benefits, Required Notice of Resignation

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Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation.

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The amount of cash deposited in financial institutions as of the balance sheet date that is insured by the Federal Deposit Insurance Corporation.

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Amount of discretionary contributions made by an employer to a defined contribution plan.

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Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan.

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Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

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Amount of damages awarded to the plaintiff in the legal matter.

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Amount of investments including trading securities, available-for-sale securities, held-to-maturity securities, and short-term investments classified as other and current.

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Commitments and Contingencies - Additional Information (Detail)			3 Months Ended			9 Months Ended		12 Months Ended
	Jul. 27, 2017	Jan. 03, 2014 USD ($)	Sep. 28, 2019 USD ($) distributor Customer Agreement	Sep. 29, 2018 USD ($) distributor	Dec. 30, 2017 USD ($)	Sep. 28, 2019 USD ($) distributor Customer Agreement	Sep. 29, 2018 USD ($) distributor	Dec. 29, 2018 USD ($)
Contingencies And Commitments [Line Items]
Company contribution percentage based on employee contribution of up to 3% of employee's compensation						3.00%
Severance plan participation agreements \| Agreement			8			8
Supplemental Unemployment Benefits, Severance Benefits, Required Notice of Resignation						6 months
Purchase Commitment, Remaining Minimum Amount Committed			$ 90,000,000.0			$ 90,000,000.0
Other Commitment			2,300,000			2,300,000
Bank balances			633,400,000			633,400,000
Short-term investments			120,000,000			120,000,000		$ 0
Cash Equivalents, at Carrying Value			513,400,000			513,400,000
Bank balance covered by Federal Deposit Insurance Corporation limit			$ 3,500,000			$ 3,500,000
Percentage Of Revenue One Customer			12.60%	12.30%		13.20%	12.40%
Percentage Of Revenue Two Customer			10.60%	9.40%		11.00%	10.40%
Concentration Risk, AR Balance One Customer \| Customer			1			1
Loss Contingency, Damages Awarded, Value			$ 10,500,000
Sales
Contingencies And Commitments [Line Items]
Concentration Risk, Just-in-time Distributors \| distributor			2	2		2	2
Accounts Receivable
Contingencies And Commitments [Line Items]
Percentage of Accounts Receivable Balance			21.40%			21.40%		13.90%
Sales Revenue, Product Line
Contingencies And Commitments [Line Items]
Percentage of Revenue - Customer Concentration			56.00%	57.10%		56.30%	57.60%
Masimo vs Former Agency Tender
Contingencies And Commitments [Line Items]
Litigation Settlement, Expense					$ 10,500,000
Proceeds from Legal Settlements								$ 2,000,000.0
Masimo vs. Physicians Healthsource, Inc.
Contingencies And Commitments [Line Items]
Loss contingency, damages sought		$ 500
United States (U.S.)
Contingencies And Commitments [Line Items]
Company's contribution to employee retirement savings plan			$ 700,000	$ 500,000		$ 1,900,000	$ 1,800,000
Chief Executive Officer
Contingencies And Commitments [Line Items]
Employment Agreement, Severance Benefits, Special Payment, Qualifying Termination						$ 292,900,000
Chief Executive Officer \| Restricted Stock Units (RSUs)
Contingencies And Commitments [Line Items]
Employment Agreement, Severance Terms	50.00%
Chief Executive Officer \| Cash Distribution
Contingencies And Commitments [Line Items]
Employment Agreement, Severance Terms	50.00%