Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Sep. 28, 2024
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business and Summary of Significant Accounting Policies	Note 1. Description of Business and Summary of Significant Accounting Policies Description of Business Lumentum Holdings Inc. (“we,” “us,” “our,” “Lumentum” or the “Company”) is an industry-leading provider of optical and photonic products essential to a range of cloud, artificial intelligence and machine learning (“AI/ML”), telecommunications, consumer, and industrial end-market applications. We operate in two end-market focused reportable segments, Cloud & Networking and Industrial Tech. Our Cloud & Networking products include a comprehensive portfolio of optical and photonic chips, modules, and subsystems supplied to cloud data center operator, AI/ML infrastructure provider, and network equipment manufacturer customers who are building cloud data center and network infrastructures. Our products enable high-capacity optical data links in cloud, AI/ML, and data center interconnect (“DCI”) applications, and communications service provider networks, including in access (local), metro (intracity), long-haul (city-to-city and worldwide), and submarine (undersea) network infrastructure. Our Cloud & Networking products also support network equipment manufacturers building enterprise network infrastructure, including storage-area networks (“SANs”), local-area networks (“LANs”) and wide-area networks (“WANs”). Demand for our Cloud & Networking products is driven by the continual growth in network capacity required for cloud computing and services, including for AI/ML, streaming video and video conferencing, wireless and mobile devices, and internet of things (“IoT”). Our Industrial Tech products include short pulse solid-state lasers, kilowatt-class fiber lasers, diode lasers, and gas lasers, which address applications in numerous end-markets. In the consumer end-market, our laser light sources are integrated into our customers’ 3D sensing cameras, which are used in mobile devices, payment kiosks, and other consumer electronics devices to enable applications including biometric identification, computational photography and virtual and augmented reality. In the automotive end-market, our lasers are used in our customers’ LiDAR and other optical sensor devices, which are increasingly being used in advanced driver assistance systems (“ADAS”) and in-cabin driver and occupant monitoring systems. In the industrial manufacturing end-market, our lasers are incorporated into our customers’ manufacturing machine tools used for the precision processing of materials in a range of industries including semiconductor device and microelectronics fabrication, electric vehicle and battery production, metal cutting and welding, and advanced manufacturing. Our products can also be used in the industrial end-market in imaging and sensing systems for process feedback and control, quality assurance, and waste reduction. Adoption of our products in the industrial end-market is driven by the needs of customers to advance semiconductor and microelectronics industry roadmaps, and by Industry 4.0/5.0 trends, including increasing manufacturing precision and flexibility and reducing waste and environmental impact. Demand for our products in the industrial end-market is driven by end-customer investments in manufacturing capacity. Our lasers also address certain semiconductor inspection and life-science applications. Basis of Presentation We have prepared the accompanying condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”), which requires management to make estimates and assumptions that affect the amounts reported in our condensed consolidated financial statements and accompanying notes. Management bases its estimates on historical experience and various other assumptions believed to be reasonable. Although these estimates are based on management’s best knowledge of current events and actions that may impact us in the future, actual results may be different from the estimates. Our interim period operating results do not necessarily indicate the results that may be expected for any other interim period or for the full fiscal year. In the opinion of the Company’s management, the information presented herein reflects all normal and recurring adjustments necessary for a fair presentation of our results of operations, financial position, stockholders’ equity, and cash flows. Our critical accounting policies are those that affect our financial statements materially and involve difficult, subjective, or complex judgments by management. Those policies are inventory valuation, revenue recognition, income taxes, goodwill, and business combinations. Our business and operating results depend significantly on general market and economic conditions. The current global macroeconomic environment is volatile and continues to be adversely impacted by inflation, a dynamic supply chain and demand environment, and signs of a weaker macroeconomic environment impacting capital expenditures across our served markets. Additionally, instability in the global credit markets, capital expenditure reductions, unemployment and other labor issues, decline in stock markets, the instability in the geopolitical environment in many parts of the world, and the current global economic challenges continue to put pressure on our business and operating results. We are continuously monitoring both the current developments in the ongoing Russia-Ukraine war including the related export controls and resulting sanctions imposed on Russia and Belarus by the U.S. and other countries, and the ongoing conflicts in the Middle East. Additional factors, such as increased inflation, escalating energy prices and the related cost increases, could continue to impact the global economy and our business. Although the global implications of these wars are difficult to predict at this time, we do not presently foresee direct material adverse effects on our business. Business Combinations On November 7, 2023, we completed the acquisition of Cloud Light Technology Limited (“Cloud Light”). We have applied the acquisition method of accounting to account for this transaction in accordance with ASC Topic 805, Business Combinations. Our condensed consolidated financial statements include the operating results of the acquired entities from the acquisition close date. Refer to “Note 4. Business Combinations” for further discussions of this transaction. Fiscal Years We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th. Every fifth or sixth fiscal year will have a 53-week period. The additional week in a 53-week year is added to the third quarter, making such quarter consist of 14 weeks. Our fiscal 2025 is a 52-week year ending on June 28, 2025, with the quarter ended September 28, 2024 being a 13-week quarterly period. Our fiscal 2024 was a 52-week year that ended on June 29, 2024, with the quarter ended September 30, 2023 being a 13-week quarterly period. Principles of Consolidation The condensed consolidated financial statements include the accounts of Lumentum Holdings Inc. and its wholly owned subsidiaries. All inter-company transactions and balances are eliminated in consolidation. Accounting Policies The condensed consolidated financial statements and accompanying notes should be read in conjunction with the audited consolidated financial statements and accompanying notes included in our Annual Report on Form 10-K for the fiscal year ended June 29, 2024. There were no significant changes to our accounting policies during the three months ended September 28, 2024