Commitments and Contingencies (Notes)	3 Months Ended
Mar. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	21. Commitments and Contingencies Employee Retirement Savings Plan The Company sponsors a qualified defined contribution plan or 401(k) plan, the Masimo Retirement Savings Plan (MRSP), covering the Company’s full-time U.S. employees who meet certain eligibility requirements. In general, the Company matches an employee’s contribution up to 3% of the employee’s compensation, subject to a maximum amount. The Company may also contribute to the MRSP on a discretionary basis. The Company contributed $0.5 million and $0.7 million to the MRSP for the three months ended March 30, 2019 and March 31, 2018, respectively. In addition, the Company also sponsors various defined contribution plans in certain locations outside of the United States (Subsidiary Plans). For each of the three months ended March 30, 2019 and March 31, 2018, the Company contributed $0.1 million to the Subsidiary Plans. Employment and Severance Agreements In July 2017, the Company entered into the First Amendment to the certain Amended and Restated Employment Agreement entered into between the Company and Mr. Kiani on November 4, 2015 (as amended, the Amended Employment Agreement). Pursuant to the terms of the Amended Employment Agreement, upon a “Qualifying Termination” (as defined in the Amended Employment Agreement), Mr. Kiani will be entitled to receive a cash severance benefit equal to two times the sum of his then-current base salary and the average annual bonus paid to Mr. Kiani during the immediately preceding three years, the full amount of the Award Shares and the full amount of the Cash Payment. In addition, in the event of a “Change in Control” (as defined in the Amended Employment Agreement) prior to a Qualifying Termination, on each of the first and second anniversaries of the Change in Control, 50% of the Cash Payment and 50% of the Award Shares will vest, subject in each case to Mr. Kiani’s continuous employment through each such anniversary date; however, in the event of a Qualifying Termination or a termination of Mr. Kiani’s employment due to death or disability prior to either of such anniversaries, any unvested amount of the Cash Payment and all of the unvested Award Shares shall vest and be paid in full. Additionally, in the event of a Change in Control prior to a Qualifying Termination, Mr. Kiani’s stock options and any other equity awards will vest in accordance with their terms, but in no event later than in two equal installments on each of the one year and two year anniversaries of the Change in Control, subject in each case to Mr. Kiani’s continuous employment through each such anniversary date. As of March 30, 2019, the expense related to the Award Shares and Cash Payment that would be recognized in the Company’s consolidated financial statements upon the occurrence of a Qualifying Termination under the Restated Employment Agreement was approximately $292.9 million. As of March 30, 2019, the Company had severance plan participation agreements with eight executive officers. The participation agreements (the Agreements) are governed by the terms and conditions of the Company’s 2007 Severance Protection Plan (the Severance Plan), which became effective on July 19, 2007 and which was amended effective December 31, 2008. Under each of the Agreements, the applicable executive officer may be entitled to receive certain salary, equity, medical and life insurance benefits if he is terminated by the Company without cause or if he terminates his employment for good reason under certain circumstances. The executive officers are also required to give the Company six months’ advance notice of their resignation under certain circumstances. Purchase Commitments Pursuant to contractual obligations with vendors, the Company had $87.3 million of purchase commitments as of March 30, 2019, which are expected to be purchased within one year. These purchase commitments have been made for certain inventory items in order to secure sufficient levels of those items and to achieve better pricing. Other Contractual Commitments In the normal course of business, the Company may provide bank guarantees to support government hospital tenders in certain foreign jurisdictions. As of March 30, 2019, the Company had approximately $1.0 million in outstanding unsecured bank guarantees. In certain circumstances, the Company also provides limited indemnification within its various customer contracts whereby the Company indemnifies the parties to whom it sells its products with respect to potential infringement of intellectual property, and against bodily injury caused by a defective Company product. It is not possible to predict the maximum potential amount of future payments under these or similar agreements, due to the conditional nature of the Company’s obligations and the unique facts and circumstances involved. As of March 30, 2019, the Company had not incurred any significant costs related to contractual indemnification of its customers. Concentrations of Risk The Company is exposed to credit loss for the amount of its cash deposits with financial institutions in excess of federally insured limits. The Company invests its excess cash in time deposits with major financial institutions. As of March 30, 2019, the Company had $412.9 million of bank balances, of which $3.5 million was covered by either the U.S. Federal Deposit Insurance Corporation limit or foreign countries’ deposit insurance organizations. While the Company and its contract manufacturers rely on sole source suppliers for certain components, steps have been taken to minimize the impact of a shortage or stoppage of shipments, such as maintaining a safety stock of inventory and designing products that could be modified to use different components. However, there can be no assurance that a shortage or stoppage of shipments of the materials or components that the Company purchases will not result in a delay in production or adversely affect the Company’s business. The Company’s ability to sell its products to U.S. hospitals depends in part on its relationships with GPOs. Many existing and potential customers for the Company’s products become members of GPOs. GPOs negotiate pricing arrangements and contracts, sometimes exclusively, with medical supply manufacturers and distributors, and these negotiated prices are made available to a GPO’s affiliated hospitals and other members. During the three months ended March 30, 2019 and March 31, 2018, revenue from the sale of the Company’s products to U.S. hospitals that are members of GPOs amounted to $129.7 million and $118.9 million, respectively. For the three months ended March 30, 2019, the Company had sales through two just-in-time distributors that represented 13.6% and 10.3% of total revenue, respectively. For the three months ended March 31, 2018, the Company had sales through the same two just-in-time distributors that represented 13.6% and 10.7% of total revenue, respectively. As of March 30, 2019, one just-in-time distributor represented 6.5% of the Company’s accounts receivable balance. As of December 29, 2018, one just-in-time distributor represented 6.7% of the Company’s accounts receivable balance. Litigation During the third quarter of fiscal year 2017, the Company became aware that certain amounts had been paid by a foreign government customer to the Company’s former appointed foreign agent in connection with a foreign government tender, but had not been remitted by such agent to the Company in accordance with the agency agreement. On December 28, 2017, the Company initiated arbitration proceedings against this foreign agent after unsuccessful attempts to recover such remittances. As a result, the Company recorded a net charge of approximately $10.5 million during the fourth quarter of fiscal year 2017 in connection with this dispute, of which $2.0 million was recovered during the year ended December 29, 2018. An arbitration hearing was held on February 11, 2019. The parties are awaiting the arbitration decision. Although the Company intends to vigorously pursue collection of the remaining amounts owed by the foreign agent, there is no guarantee that the Company will be successful in these efforts. On January 2, 2014, a putative class action complaint was filed against the Company in the U.S. District Court for the Central District of California by Physicians Healthsource, Inc. (PHI). The complaint alleges that the Company sent unsolicited facsimile advertisements in violation of the Junk Fax Protection Act of 2005 and related regulations. The complaint seeks $500 for each alleged violation, treble damages if the District Court finds the alleged violations to be knowing, plus interest, costs and injunctive relief. On April 14, 2014, the Company filed a motion to stay the case pending a decision on a related petition filed by the Company with the Federal Communications Commission (FCC). On May 22, 2014, the District Court granted the motion and stayed the case pending a ruling by the FCC on the petition. On October 30, 2014, the FCC granted some of the relief and denied some of the relief requested in the Company’s petition. Both parties appealed the FCC’s decision on the petition. On November 25, 2014, the District Court granted the parties’ joint request that the stay remain in place pending a decision on the appeal. On March 31, 2017, the D.C. Circuit Court of Appeals vacated and remanded the FCC’s decision, holding that the applicable FCC rule was unlawful to the extent it requires opt-out notices on solicited faxes. On April 28, 2017, PHI filed a petition seeking rehearing by the D.C. Circuit Court of Appeals. The D.C. Circuit Court of Appeals denied the requested rehearing on June 6, 2017. The plaintiff filed a petition for a writ of certiorari with the United States Supreme Court on September 5, 2017 seeking review of the D.C. Circuit Court of Appeals’ decision. The Company and the FCC filed oppositions to this petition on January 16, 2018. On February 20, 2018, the Supreme Court denied certiorari. The District Court lifted the stay on April 9, 2018 and set a trial date of November 5, 2019. The current deadline for PHI to file its motion for class certification is May 20, 2019. The Company believes it has good and substantial defenses to the claims in the District Court litigation, but there is no guarantee that the Company will prevail. The Company is unable to determine whether any loss will ultimately occur or to estimate the range of such loss; therefore, no amount of loss has been accrued by the Company in the accompanying condensed consolidated financial statements. From time to time, the Company may be involved in other litigation and investigations relating to claims and matters arising out of its operations in the normal course of business. The Company believes that it currently is not a party to any other legal proceedings which, individually or in the aggregate, would have a material adverse effect on its consolidated financial position, results of operations or cash flows.

21. Commitments and Contingencies

Employee Retirement Savings Plan

The Company sponsors a qualified defined contribution plan or 401(k) plan, the Masimo Retirement Savings Plan (MRSP), covering the Company’s full-time U.S. employees who meet certain eligibility requirements. In general, the Company matches an employee’s contribution up to 3% of the employee’s compensation, subject to a maximum amount. The Company may also contribute to the MRSP on a discretionary basis. The Company contributed $0.5 million and $0.7 million to the MRSP for the three months ended March 30, 2019 and March 31, 2018, respectively.

In addition, the Company also sponsors various defined contribution plans in certain locations outside of the United States (Subsidiary Plans). For each of the three months ended March 30, 2019 and March 31, 2018, the Company contributed $0.1 million to the Subsidiary Plans.

Employment and Severance Agreements

In July 2017, the Company entered into the First Amendment to the certain Amended and Restated Employment Agreement entered into between the Company and Mr. Kiani on November 4, 2015 (as amended, the Amended Employment Agreement). Pursuant to the terms of the Amended Employment Agreement, upon a “Qualifying Termination” (as defined in the Amended Employment Agreement), Mr. Kiani will be entitled to receive a cash severance benefit equal to two times the sum of his then-current base salary and the average annual bonus paid to Mr. Kiani during the immediately preceding three years, the full amount of the Award Shares and the full amount of the Cash Payment. In addition, in the event of a “Change in Control” (as defined in the Amended Employment Agreement) prior to a Qualifying Termination, on each of the first and second anniversaries of the Change in Control, 50% of the Cash Payment and 50% of the Award Shares will vest, subject in each case to Mr. Kiani’s continuous employment through each such anniversary date; however, in the event of a Qualifying Termination or a termination of Mr. Kiani’s employment due to death or disability prior to either of such anniversaries, any unvested amount of the Cash Payment and all of the unvested Award Shares shall vest and be paid in full. Additionally, in the event of a Change in Control prior to a Qualifying Termination, Mr. Kiani’s stock options and any other equity awards will vest in accordance with their terms, but in no event later than in two equal installments on each of the one year and two year anniversaries of the Change in Control, subject in each case to Mr. Kiani’s continuous employment through each such anniversary date. As of March 30, 2019, the expense related to the Award Shares and Cash Payment that would be recognized in the Company’s consolidated financial statements upon the occurrence of a Qualifying Termination under the Restated Employment Agreement was approximately $292.9 million.

As of March 30, 2019, the Company had severance plan participation agreements with eight executive officers. The participation agreements (the Agreements) are governed by the terms and conditions of the Company’s 2007 Severance Protection Plan (the Severance Plan), which became effective on July 19, 2007 and which was amended effective December 31, 2008. Under each of the Agreements, the applicable executive officer may be entitled to receive certain salary, equity, medical and life insurance benefits if he is terminated by the Company without cause or if he terminates his employment for good reason under certain circumstances. The executive officers are also required to give the Company six months’ advance notice of their resignation under certain circumstances.

Purchase Commitments

Pursuant to contractual obligations with vendors, the Company had $87.3 million of purchase commitments as of March 30, 2019, which are expected to be purchased within one year. These purchase commitments have been made for certain inventory items in order to secure sufficient levels of those items and to achieve better pricing.

Other Contractual Commitments

In the normal course of business, the Company may provide bank guarantees to support government hospital tenders in certain foreign jurisdictions. As of March 30, 2019, the Company had approximately $1.0 million in outstanding unsecured bank guarantees.

In certain circumstances, the Company also provides limited indemnification within its various customer contracts whereby the Company indemnifies the parties to whom it sells its products with respect to potential infringement of intellectual property, and against bodily injury caused by a defective Company product. It is not possible to predict the maximum potential amount of future payments under these or similar agreements, due to the conditional nature of the Company’s obligations and the unique facts and circumstances involved. As of March 30, 2019, the Company had not incurred any significant costs related to contractual indemnification of its customers.

Concentrations of Risk

The Company is exposed to credit loss for the amount of its cash deposits with financial institutions in excess of federally insured limits. The Company invests its excess cash in time deposits with major financial institutions. As of March 30, 2019, the Company had $412.9 million of bank balances, of which $3.5 million was covered by either the U.S. Federal Deposit Insurance Corporation limit or foreign countries’ deposit insurance organizations.

While the Company and its contract manufacturers rely on sole source suppliers for certain components, steps have been taken to minimize the impact of a shortage or stoppage of shipments, such as maintaining a safety stock of inventory and designing products that could be modified to use different components. However, there can be no assurance that a shortage or stoppage of shipments of the materials or components that the Company purchases will not result in a delay in production or adversely affect the Company’s business.

The Company’s ability to sell its products to U.S. hospitals depends in part on its relationships with GPOs. Many existing and potential customers for the Company’s products become members of GPOs. GPOs negotiate pricing arrangements and contracts, sometimes exclusively, with medical supply manufacturers and distributors, and these negotiated prices are made available to a GPO’s affiliated hospitals and other members. During the three months ended March 30, 2019 and March 31, 2018, revenue from the sale of the Company’s products to U.S. hospitals that are members of GPOs amounted to $129.7 million and $118.9 million, respectively.

For the three months ended March 30, 2019, the Company had sales through two just-in-time distributors that represented 13.6% and 10.3% of total revenue, respectively. For the three months ended March 31, 2018, the Company had sales through the same two just-in-time distributors that represented 13.6% and 10.7% of total revenue, respectively.

As of March 30, 2019, one just-in-time distributor represented 6.5% of the Company’s accounts receivable balance. As of December 29, 2018, one just-in-time distributor represented 6.7% of the Company’s accounts receivable balance.

Litigation

During the third quarter of fiscal year 2017, the Company became aware that certain amounts had been paid by a foreign government customer to the Company’s former appointed foreign agent in connection with a foreign government tender, but had not been remitted by such agent to the Company in accordance with the agency agreement. On December 28, 2017, the Company initiated arbitration proceedings against this foreign agent after unsuccessful attempts to recover such remittances. As a result, the Company recorded a net charge of approximately $10.5 million during the fourth quarter of fiscal year 2017 in connection with this dispute, of which $2.0 million was recovered during the year ended December 29, 2018. An arbitration hearing was held on February 11, 2019. The parties are awaiting the arbitration decision. Although the Company intends to vigorously pursue collection of the remaining amounts owed by the foreign agent, there is no guarantee that the Company will be successful in these efforts.

On January 2, 2014, a putative class action complaint was filed against the Company in the U.S. District Court for the Central District of California by Physicians Healthsource, Inc. (PHI). The complaint alleges that the Company sent unsolicited facsimile advertisements in violation of the Junk Fax Protection Act of 2005 and related regulations. The complaint seeks $500 for each alleged violation, treble damages if the District Court finds the alleged violations to be knowing, plus interest, costs and injunctive relief. On April 14, 2014, the Company filed a motion to stay the case pending a decision on a related petition filed by the Company with the Federal Communications Commission (FCC). On May 22, 2014, the District Court granted the motion and stayed the case pending a ruling by the FCC on the petition. On October 30, 2014, the FCC granted some of the relief and denied some of the relief requested in the Company’s petition. Both parties appealed the FCC’s decision on the petition. On November 25, 2014, the District Court granted the parties’ joint request that the stay remain in place pending a decision on the appeal. On March 31, 2017, the D.C. Circuit Court of Appeals vacated and remanded the FCC’s decision, holding that the applicable FCC rule was unlawful to the extent it requires opt-out notices on solicited faxes. On April 28, 2017, PHI filed a petition seeking rehearing by the D.C. Circuit Court of Appeals. The D.C. Circuit Court of Appeals denied the requested rehearing on June 6, 2017. The plaintiff filed a petition for a writ of certiorari with the United States Supreme Court on September 5, 2017 seeking review of the D.C. Circuit Court of Appeals’ decision. The Company and the FCC filed oppositions to this petition on January 16, 2018. On February 20, 2018, the Supreme Court denied certiorari. The District Court lifted the stay on April 9, 2018 and set a trial date of November 5, 2019. The current deadline for PHI to file its motion for class certification is May 20, 2019. The Company believes it has good and substantial defenses to the claims in the District Court litigation, but there is no guarantee that the Company will prevail. The Company is unable to determine whether any loss will ultimately occur or to estimate the range of such loss; therefore, no amount of loss has been accrued by the Company in the accompanying condensed consolidated financial statements.

From time to time, the Company may be involved in other litigation and investigations relating to claims and matters arising out of its operations in the normal course of business. The Company believes that it currently is not a party to any other legal proceedings which, individually or in the aggregate, would have a material adverse effect on its consolidated financial position, results of operations or cash flows.