Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Jul. 02, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Unaudited Interim Financial Information—The accompanying unaudited, condensed consolidated financial statements have been prepared according to the rules and regulations of the United States (the “U.S.”) Securities and Exchange Commission (the “SEC”) and, in the opinion of management, reflect all adjustments, which include normal recurring adjustments, necessary for a fair statement of the condensed consolidated balance sheets, condensed consolidated statements of operations, comprehensive income (loss), stockholders' equity and cash flows of MACOM Technology Solutions Holdings, Inc. (“MACOM”, the “Company”, “us”, “we” or “our”) for the periods presented. We prepare our interim financial information using the same accounting principles we use for our annual audited consolidated financial statements. Certain information and note disclosures normally included in the annual audited consolidated financial statements have been condensed or omitted in accordance with prescribed SEC rules. We believe that the disclosures made in our condensed consolidated financial statements and the accompanying notes are adequate to make the information presented not misleading. The condensed consolidated balance sheet as of October 2, 2020 is as reported in our audited consolidated financial statements as of that date. Our accounting policies are described in the notes to our October 2, 2020 consolidated financial statements, which were included in our Annual Report on Form 10-K for our fiscal year ended October 2, 2020 filed with the SEC on November 18, 2020 (the “2020 Annual Report on Form 10-K”). We recommend that the financial statements included in this Quarterly Report on Form 10-Q be read in conjunction with the consolidated financial statements and notes included in our 2020 Annual Report on Form 10-K. Principles of Consolidation—The accompanying condensed consolidated financial statements include our accounts and the accounts of our majority-owned subsidiaries. All intercompany balances and transactions have been eliminated in consolidation. We have a 52- or 53-week fiscal year ending on the Friday closest to the last day of September. Fiscal year 2021 includes 52 weeks and fiscal year 2020 included 53 weeks. To offset the effect of holidays, for fiscal years in which there are 53 weeks, we include the extra week arising in such fiscal years in the first fiscal quarter. Our first fiscal quarter ended January 1, 2021 included 13 weeks and the first fiscal quarter ended January 3, 2020 had 14 weeks. Use of Estimates—The preparation of condensed consolidated financial statements in conformity with U.S. generally accepted accounting principles (“GAAP”) requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities during the reporting periods, the reported amounts of revenue and expenses during the reporting periods, and the disclosure of contingent assets and liabilities at the date of the financial statements. On an ongoing basis, we base estimates and assumptions on historical experience, currently available information and various other factors that management believes to be reasonable under the circumstances. Actual results may differ materially from these estimates and assumptions. The accounting policies which our management believes involve the most significant application of judgment or involve complex estimation, are inventories and associated reserves; goodwill and long-lived asset valuations and associated impairment assessments; fair value of convertible debt; revenue reserves; share-based compensation valuations and income taxes. Recent Accounting Pronouncements—Our Recent Accounting Pronouncements are described in the 2020 Annual Report on Form 10-K. Pronouncements Adopted in Fiscal Year 2021 On the first day of fiscal year 2021, we adopted Accounting Standards Update (“ASU”) 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. This ASU introduces a new accounting model known as Credit Expected Credit Losses (“CECL”), which requires earlier recognition of credit losses. The CECL model utilizes a lifetime expected credit loss measurement objective for the recognition of credit losses for receivables at the time the financial asset is originated or acquired, replacing the current incurred loss methodology that delays recognition of credit losses until a probable loss has been incurred. There are other provisions within the standard affecting how impairments of other financial assets may be recorded and presented, as well as expanded disclosures. There was no impact to our unaudited condensed consolidated financial statements from the adoption of this guidance. We generate accounts receivable from customers and they are classified as short-term. We monitor collections and maintain a provision for expected credit losses based on historical trends, current conditions, and relevant forecasted information, in addition to provisions established for any specific collection issues that have been identified. As of July 2, 2021, our allowance for expected credit losses was less than $0.1 million. Our investments in debt securities, which are classified as available-for-sale, are further disclosed in Note 3, Investments. As of July 2, 2021, our available-for-sale debt securities had gross unrealized losses of $0.1 million, which we believe to be temporary, and therefore there is no allowance for credit losses recorded in our condensed consolidated statement of operations. In January 2017, the Financial Accounting Standards Board (the “FASB”) issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment. ASU 2017-04 simplifies the subsequent measurement of goodwill by eliminating Step 2 from the goodwill impairment test. Instead, a one-step quantitative impairment test calculates goodwill impairment as the excess of the carrying value of a reporting unit over its fair value, up to the carrying value of the goodwill. This ASU should be applied on a prospective basis. We adopted this ASU in the first quarter of fiscal year 2021 and the adoption of this update did not have an impact on our condensed consolidated financial statements and related disclosures. In August 2018, the FASB issued ASU 2018-15, Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract, to provide additional guidance on the accounting for costs of implementing cloud computing arrangements that are service contracts, and requiring customers in such arrangements to follow the guidance in Subtopic 350-40. The amendments in this update require the capitalization of implementation costs during the application development stage of such hosting arrangements and amortization of the expense over the term of the arrangement beginning when the module or component of the hosting arrangement is ready for its intended use. Capitalized implementation costs and amortization thereof are also required to be classified in the same line item in the statements of financial position, operations and cash flows associated with the hosting service fees. We adopted this ASU in the first quarter of fiscal year 2021 and selected prospective application to all implementation costs incurred after the adoption date. The adoption of this update did not have an impact on our condensed consolidated financial statements and related disclosures. Pronouncements for Adoption in Subsequent Periods In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting, which provides optional expedients and exceptions to applying the guidance on contract modifications, hedge accounting, and other transactions, to simplify the accounting for transitioning from the London Interbank Offered Rate, and other interbank offered rates expected to be discontinued, to alternative reference rates. The guidance in this update was effective upon its issuance. If elected, the guidance is to be applied prospectively through December 31, 2022. We are currently evaluating the effect the potential adoption of this ASU will have on our consolidated financial statements, including, but not limited to, our Credit Agreement (defined below). For additional information regarding our Credit Agreement, refer to Note 8 - Debt. In August 2020, the FASB issued ASU 2020-06, Debt—Debt with Conversion and Other Options (Subtopic 470-20) and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40): Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity, which simplifies the accounting for certain financial instruments with characteristics of liability and equity, including convertible instruments and contracts on an entity’s own equity. The standard reduces the number of models used to account for convertible instruments, removes certain settlement conditions that are required for equity contracts to qualify for the derivative scope exception, and requires the if-converted method for calculation of diluted earnings per share for all convertible instruments. The standard is effective for public companies for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2021. Early adoption is permitted, but no earlier than fiscal years beginning after December 15, 2020. We are evaluating the impact to our financial statements and expect that the resulting impact will be to reclassify the equity component of our 2026 Convertible Notes (as defined below) of $79.7 million from additional paid-in capital to long-term debt, up to the par value, with the remainder to accumulated deficit. On a prospective basis, there will be a reduction of our reported interest expense on our 2026 Convertible Notes to their stated 0.25% coupon rate. For additional information regarding our debt, refer to Note 8 - Debt.