Concentration Risk, Just-in-time Distributors

No definition available.

Name:	masi_ConcentrationRiskJustintimeDistributors
Namespace Prefix:	masi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	masi_ContingenciesAndCommitmentsLineItems
Namespace Prefix:	masi_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Initial term of Executive Employment agreement.

+ References

No definition available.

+ Details

Name:	masi_InitialTermOfExecutiveEmploymentAgreement
Namespace Prefix:	masi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

The range of interest rates for all capital leases as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	masi_InterestRatesOnCapitalLease
Namespace Prefix:	masi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Loss Contingency, Damages Sought, Value Per Violation

+ References

No definition available.

+ Details

Name:	masi_LossContingencyDamagesSoughtValuePerViolation
Namespace Prefix:	masi_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of Former Sales Representatives

+ References

No definition available.

+ Details

Name:	masi_NumberofFormerSalesRepresentatives
Namespace Prefix:	masi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Participants in the Surfactant, Positive Pressure, and Oxygenation Randomized Trial

+ References

No definition available.

+ Details

Name:	masi_NumberofParticipantsintheSurfactantPositivePressureandOxygenationRandomizedTrial
Namespace Prefix:	masi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage Of Accounts Receivable Balance From Three Just In Time Distributors

+ References

No definition available.

+ Details

Name:	masi_PercentageOfAccountsReceivableBalanceFromThreeJustInTimeDistributors
Namespace Prefix:	masi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage Of Accounts Receivable Balance From Two Just In Time Distributor

+ References

No definition available.

+ Details

Name:	masi_PercentageOfAccountsReceivableBalanceFromTwoJustInTimeDistributor
Namespace Prefix:	masi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	masi_PercentageOfRevenueOneCustomer
Namespace Prefix:	masi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of revenue two customer.

+ References

No definition available.

+ Details

Name:	masi_PercentageOfRevenueTwoCustomer
Namespace Prefix:	masi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Sales of products to customers affiliated with Group Purchasing Organizations.

+ References

No definition available.

+ Details

Name:	masi_RevenueCustomerConcentration
Namespace Prefix:	masi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	masi_Royalty
Namespace Prefix:	masi_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Royalty rate Percentage.

+ References

No definition available.

+ Details

Name:	masi_RoyaltyRatePercentage
Namespace Prefix:	masi_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Severance plan participation agreements.

+ References

No definition available.

+ Details

Name:	masi_SeverancePlanParticipationAgreements
Namespace Prefix:	masi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Supplemental Unemployment Benefits, Severance Benefits, Required Notice of Resignation

+ References

No definition available.

+ Details

Name:	masi_SupplementalUnemploymentBenefitsSeveranceBenefitsRequiredNoticeofResignation
Namespace Prefix:	masi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph a

-Article 7

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 15

-Subparagraph 5

-Article 9

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.15(5))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_AccruedRentCurrentAndNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_Cash
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_CashFDICInsuredAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanEmployerDiscretionaryContributionAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

No definition available.

+ Details

Name:	us-gaap_LeaseAndRentalExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of judgment or settlement awarded to (against) the entity in respect of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of increase (decrease) in loss contingency liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

+ Details

Name:	us-gaap_LossContingencyAccrualCarryingValuePeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

- Definition

The total number of new claims filed pertaining to a loss contingency during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 450

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14435-108349

+ Details

Name:	us-gaap_LossContingencyNewClaimsFiledNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of another entity's patents that the entity has allegedly infringed.

+ References

No definition available.

+ Details

Name:	us-gaap_LossContingencyPatentsAllegedlyInfringedNumber
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

+ Details

Name:	us-gaap_MoneyMarketFundsAtCarryingValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

+ References

No definition available.

+ Details

Name:	us-gaap_OtherCommitment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Minimum amount to be expended to satisfy the terms of arrangements in which the entity has agreed to expend funds to procure goods or services, excluding long-term purchase commitments or unconditional purchase obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.25)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 25

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 19

-Article 7

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 17

-Article 9

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.17)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.(a)(19))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

Name:	us-gaap_PurchaseCommitmentRemainingMinimumAmountCommitted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	dei_LegalEntityAxis=masi_PhilipsPatentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=us-gaap_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByBenchmarkAxis=us-gaap_SalesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=masi_JustintimedistributoroneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=masi_JustInTimeDistributorThreeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConcentrationRiskByTypeAxis=masi_JustintimedistributortwoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=masi_Masimovs.MindrayDSUSAInc.andShenzhenMindrayBioMedicalElectronicsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=masi_Masimovs.PhilipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=masi_Masimovs.PhysiciansHealthsourceInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LitigationCaseAxis=masi_MasimovsFormerPhysicianOfficeSalesRepresentativesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_SalesRevenueProductLineMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended	3 Months Ended		12 Months Ended	0 Months Ended			12 Months Ended	0 Months Ended
	Oct. 01, 2014	Sep. 30, 2011 sales_representatives	Apr. 04, 2015 Agreement	Mar. 29, 2014	Jan. 03, 2015 distributor	Jul. 09, 2009 patent	Aug. 21, 2013 claim	Jan. 16, 2014	Dec. 28, 2013	Jan. 03, 2014	Jan. 31, 2014 participant
Contingencies And Commitments [Line Items]
Accrued rent expense			$ 400,000us-gaap_AccruedRentCurrentAndNoncurrent
Rental expense related to operating leases			1,500,000us-gaap_LeaseAndRentalExpense	1,600,000us-gaap_LeaseAndRentalExpense
Company contribution percentage based on employee contribution of up to 3% of employee's compensation			3.00%
Company's contribution to employee retirement savings plan			600,000	600,000
Initial term of agreement			3 years
Severance plan participation agreements			7
Supplemental Unemployment Benefits, Severance Benefits, Required Notice of Resignation			6 months
Purchase Commitment, Remaining Minimum Amount Committed			71,600,000
Bank balances			78,300,000us-gaap_Cash		92,900,000us-gaap_Cash
Bank balance covered by Federal Deposit Insurance Corporation limit			3,200,000us-gaap_CashFDICInsuredAmount
Money Market Funds, at Carrying Value			13,900,000us-gaap_MoneyMarketFundsAtCarryingValue		1,100,000us-gaap_MoneyMarketFundsAtCarryingValue
Money market funds			400,000us-gaap_OtherCommitment
Percentage of revenue one customer			14.00%masi_PercentageOfRevenueOneCustomer	15.00%masi_PercentageOfRevenueOneCustomer
Percentage of revenue two customer			13.00%masi_PercentageOfRevenueTwoCustomer	9.00%masi_PercentageOfRevenueTwoCustomer
Royalty			7,180,000masi_Royalty	7,582,000masi_Royalty
Royalty Rate Percentage			7.75%masi_RoyaltyRatePercentage
Number of former sales representatives		2masi_NumberofFormerSalesRepresentatives
Litigation settlement amount	466,800,000us-gaap_LitigationSettlementAmount
Increase (decrease) in loss contingency accrual				(8,000,000)
Number of participants in the surfactant, positive pressure, and oxygenation randomized trial											2
Sales
Contingencies And Commitments [Line Items]
Concentration risk, just-in-time distributors			2	2	3
Minimum
Contingencies And Commitments [Line Items]
Interest rates on capital lease			4.30%
Maximum
Contingencies And Commitments [Line Items]
Interest rates on capital lease			12.00%
Sales Revenue, Product Line [Member]
Contingencies And Commitments [Line Items]
Sale of company's products to customers			86,300,000	75,200,000
Just in time distributor one
Contingencies And Commitments [Line Items]
Percentage Of Accounts Receivable Balance From Three Just In Time Distributors					6.00%
Percentage of accounts receivable balance from two just-in-time distributor			11.00%
Just in time distributor two
Contingencies And Commitments [Line Items]
Percentage Of Accounts Receivable Balance From Three Just In Time Distributors					9.00%
Percentage of accounts receivable balance from two just-in-time distributor			7.00%
Just In Time Distributor Three [Member]
Contingencies And Commitments [Line Items]
Percentage Of Accounts Receivable Balance From Three Just In Time Distributors					5.00%
Masimo vs. Philips
Contingencies And Commitments [Line Items]
Number of patents allegedly infringed						1
Masimo vs. Mindray DS USA, Inc. and Shenzhen Mindray Bio-Medical Electronics
Contingencies And Commitments [Line Items]
Loss contingency, new claims filed							2
Masimo vs Former Physician Office Sales Representatives
Contingencies And Commitments [Line Items]
Litigation settlement amount								5,400,000
Litigation settlement expense									2,600,000
Masimo vs. Physicians Healthsource, Inc.
Contingencies And Commitments [Line Items]
Loss contingency, damages sought										$ 500
Parent Company [Member]
Contingencies And Commitments [Line Items]
Number of patents allegedly infringed						2
Philips Patent [Member]
Contingencies And Commitments [Line Items]
Number of patents allegedly infringed						1