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Percentage Of Accounts Receivable Balance From Two Just In Time Distributor

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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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Sales of products to customers affiliated with Group Purchasing Organizations.

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Royalty revenue earned during the period from a third party resulting from a settlement agreement.

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Severance plan participation agreements.

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Carrying value as of the balance sheet date of obligations incurred through that date and payable for contractual rent under lease arrangements.

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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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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 rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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

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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 ($)	Sep. 29, 2018 USD ($) distributor Agreement	Sep. 30, 2017 USD ($) distributor	Sep. 29, 2018 USD ($) distributor Agreement	Sep. 30, 2017 USD ($) distributor	Dec. 30, 2017 USD ($) distributor	Dec. 28, 2013 USD ($)	Jan. 31, 2014 participant
Contingencies And Commitments [Line Items]
Accrued rent expense			$ 1,500,000		$ 1,500,000		$ 1,500,000
Rental expense related to operating leases			$ 1,700,000	$ 1,700,000	$ 5,200,000	$ 5,000,000
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			$ 80,600,000		$ 80,600,000
Other Commitment			1,100,000		1,100,000
Bank balances			493,500,000		493,500,000
Bank balance covered by Federal Deposit Insurance Corporation limit			$ 3,400,000		$ 3,400,000
Percentage Of Revenue One Customer			12.30%	12.30%	12.40%	13.20%
Percentage Of Revenue Two Customer			9.40%	10.90%	10.40%	11.40%
Royalty			$ 8,100,000	$ 8,400,000	$ 25,300,000	$ 25,700,000
Number of participants in the surfactant, positive pressure, and oxygenation randomized trial \| participant									2
Sales [Member]
Contingencies And Commitments [Line Items]
Concentration Risk, Just-in-time Distributors \| distributor			2	2	2	2
Accounts Receivable [Member]
Contingencies And Commitments [Line Items]
Concentration Risk, Just-in-time Distributors \| distributor					1		1
Sales Revenue, Product Line [Member]
Contingencies And Commitments [Line Items]
Revenue Customer Concentration			$ 115,300,000	$ 102,700,000	$ 350,200,000	$ 308,000,000
Just in time distributor two [Member]
Contingencies And Commitments [Line Items]
Percentage Of Accounts Receivable Balance From Two Just In Time Distributor					5.30%
Just in time distributor one [Member]
Contingencies And Commitments [Line Items]
Percentage Of Accounts Receivable Balance From Two Just In Time Distributor							6.50%
Masimo vs Former Agency Tender [Member]
Contingencies And Commitments [Line Items]
Litigation Settlement, Expense								$ 10,500,000
Proceeds from Legal Settlements								400,000
Masimo vs Former Physician Office Sales Representatives [Member]
Contingencies And Commitments [Line Items]
Litigation Settlement, Expense								$ 2,600,000
Litigation Settlement, Interest Rate								10.00%
Masimo vs. Physicians Healthsource, Inc.
Contingencies And Commitments [Line Items]
Loss contingency, damages sought		$ 500
International
Contingencies And Commitments [Line Items]
Company's contribution to employee retirement savings plan			100,000	100,000	$ 300,000	200,000
United States
Contingencies And Commitments [Line Items]
Company's contribution to employee retirement savings plan			$ 500,000	$ 600,000		$ 1,800,000
Chief Executive Officer [Member]
Contingencies And Commitments [Line Items]
Employment Agreement, Severance Benefits, Special Payment, Qualifying Termination					$ 292,900,000
Chief Executive Officer [Member] \| Restricted Stock Units (RSUs) [Member]
Contingencies And Commitments [Line Items]
Employment Agreement, Severance Terms	50.00%
Chief Executive Officer [Member] \| Cash Distribution [Member]
Contingencies And Commitments [Line Items]
Employment Agreement, Severance Terms	50.00%