Description of Business and Summary of Significant Accounting Policies	3 Months Ended
Sep. 26, 2015
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 We are an industry leading provider of optical and photonic products addressing a range of end markets including data communications (“Datacom”) and telecommunications (“Telecom”) networking, and industrial and commercial lasers (“commercial lasers”) for manufacturing, inspection and life-science applications. Basis of Presentation On August 1, 2015, Lumentum became an independent publicly-traded company through the distribution by JDSU to its stockholders of 80.1% of our outstanding common stock (the “Separation”). Each JDSU stockholder of record as of the close of business on July 27, 2015 received one share of Lumentum common stock for every five shares of JDSU common stock held on the record date. JDSU was renamed Viavi and at the time of the distribution retained ownership of 19.9% of Lumentum’s outstanding shares. Lumentum was incorporated in Delaware as a wholly owned subsidiary of Viavi on February 10, 2015 and is comprised of the former communications and commercial optical products (“CCOP”) segment and WaveReady product lines of Viavi. Lumentum’s Registration Statement on Form 10 was declared effective by the U.S. Securities and Exchange Commission (“SEC”) on July 16, 2015. Lumentum’s common stock began trading “regular-way” under the ticker “LITE” on the NASDAQ stock market on August 4, 2015. On July 31, 2015, prior to the Separation, Viavi transferred substantially all of the assets and liabilities and operations of the communications and commercial optical products (“CCOP”) segment and WaveReady product lines to Lumentum (the “Capitalization"). Combined financial statements for periods prior to the Capitalization were prepared on a stand-alone basis and were derived from Viavi’s consolidated financial statements and accounting records. For the three months ended September 26, 2015, expenses were allocated to us using estimates that we consider to be a reasonable reflection of the utilization of services provided to or benefits received by us. The preparation of the consolidated financial statements in accordance with GAAP in the U.S. requires management to make estimates and assumptions that affect the amounts reported in our 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 the company in the future, actual results may be different from the estimates. Our critical accounting policies are those that affect our financial statements materially and involve difficult, subjective or complex judgments by management. Those policies are revenue recognition, inventory valuation, allocation methods and allocated expenses from Viavi, valuation of goodwill and other intangible assets, share-based compensation, retirement and post-retirement plan assumptions, restructuring, warranty and accounting for income taxes. See “Note 3. Related Party Transactions” in the consolidated financial statements for further information regarding the relationships we had with Viavi and other Viavi entities. Our consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC and are in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). In the opinion of management, these consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the consolidated financial statements for the periods shown. The results of operations for such periods are not necessarily indicative of the results expected for the full year or for any future periods. Fiscal Years We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th. Our fiscal 2016 is a 53-week year ending on July 2, 2016. Our fiscal 2015 ended on June 27, 2015 and was a 52-week year. Our fiscal 2014 ended on June 28, 2014 and was a 52-week year. Principles of Consolidation The consolidated financial statements include certain assets and liabilities that were historically held at the Viavi level which were specifically identifiable or otherwise attributable to us. All intra-company transactions within our business were eliminated. All significant transactions between us and other businesses of Viavi prior to separation were reflected as net transfers to and from Viavi in the consolidated statement of stockholders’ equity and as a component of financing activities in the consolidated statement of cash flows Use of Estimates The preparation of our consolidated financial statements in conformity with U.S. GAAP requires Management to make estimates and assumptions that affect the reported amount of assets and liabilities at the date of the financial statements, the reported amount of net revenue and expenses and the disclosure of commitments and contingencies during the reporting periods. We base estimates on historical experience and on various assumptions about the future believed to be reasonable based on available information. Our reported financial position or results of operations may be materially different under changed conditions or when using different estimates and assumptions, particularly with respect to significant accounting policies. If estimates or assumptions differ from actual results, subsequent periods are adjusted to reflect more current information. Accounting Policies There have been no material changes in our significant accounting policies during the three months ended September 26, 2015 compared to the significant accounting policies described in our Annual Report on Form 10-K/A for the fiscal year ended June 27, 2015. The accompanying unaudited interim consolidated financial statements and accompanying related notes should be read in conjunction with the consolidated financial statements and related notes included in our Annual Report on Form 10-K/A for the fiscal year ended June 27, 2015.

Note 1. Description of Business and Summary of Significant Accounting Policies

Description of Business

We are an industry leading provider of optical and photonic products addressing a range of end markets including data communications (“Datacom”) and telecommunications (“Telecom”) networking, and industrial and commercial lasers (“commercial lasers”) for manufacturing, inspection and life-science applications.

Basis of Presentation

On August 1, 2015, Lumentum became an independent publicly-traded company through the distribution by JDSU to its stockholders of 80.1% of our outstanding common stock (the “Separation”). Each JDSU stockholder of record as of the close of business on July 27, 2015 received one share of Lumentum common stock for every five shares of JDSU common stock held on the record date. JDSU was renamed Viavi and at the time of the distribution retained ownership of 19.9% of Lumentum’s outstanding shares. Lumentum was incorporated in Delaware as a wholly owned subsidiary of Viavi on February 10, 2015 and is comprised of the former communications and commercial optical products (“CCOP”) segment and WaveReady product lines of Viavi. Lumentum’s Registration Statement on Form 10 was declared effective by the U.S. Securities and Exchange Commission (“SEC”) on July 16, 2015. Lumentum’s common stock began trading “regular-way” under the ticker “LITE” on the NASDAQ stock market on August 4, 2015.

On July 31, 2015, prior to the Separation, Viavi transferred substantially all of the assets and liabilities and operations of the communications and commercial optical products (“CCOP”) segment and WaveReady product lines to Lumentum (the “Capitalization"). Combined financial statements for periods prior to the Capitalization were prepared on a stand-alone basis and were derived from Viavi’s consolidated financial statements and accounting records. For the three months ended September 26, 2015, expenses were allocated to us using estimates that we consider to be a reasonable reflection of the utilization of services provided to or benefits received by us.

The preparation of the consolidated financial statements in accordance with GAAP in the U.S. requires management to make estimates and assumptions that affect the amounts reported in our 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 the company in the future, actual results may be different from the estimates. Our critical accounting policies are those that affect our financial statements materially and involve difficult, subjective or complex judgments by management. Those policies are revenue recognition, inventory valuation, allocation methods and allocated expenses from Viavi, valuation of goodwill and other intangible assets, share-based compensation, retirement and post-retirement plan assumptions, restructuring, warranty and accounting for income taxes.

See “Note 3. Related Party Transactions” in the consolidated financial statements for further information regarding the relationships we had with Viavi and other Viavi entities.

Our consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC and are in conformity with U.S. generally accepted accounting principles (“U.S. GAAP”). In the opinion of management, these consolidated financial statements reflect all adjustments, consisting only of normal recurring adjustments, which are necessary for a fair statement of the consolidated financial statements for the periods shown. The results of operations for such periods are not necessarily indicative of the results expected for the full year or for any future periods.

Fiscal Years

We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th. Our fiscal 2016 is a 53-week year ending on July 2, 2016. Our fiscal 2015 ended on June 27, 2015 and was a 52-week year. Our fiscal 2014 ended on June 28, 2014 and was a 52-week year.

Principles of Consolidation

The consolidated financial statements include certain assets and liabilities that were historically held at the Viavi level which were specifically identifiable or otherwise attributable to us. All intra-company transactions within our business were eliminated. All significant transactions between us and other businesses of Viavi prior to separation were reflected as net transfers to and from Viavi in the consolidated statement of stockholders’ equity and as a component of financing activities in the consolidated statement of cash flows

Use of Estimates

The preparation of our consolidated financial statements in conformity with U.S. GAAP requires Management to make estimates and assumptions that affect the reported amount of assets and liabilities at the date of the financial statements, the reported amount of net revenue and expenses and the disclosure of commitments and contingencies during the reporting periods. We base estimates on historical experience and on various assumptions about the future believed to be reasonable based on available information. Our reported financial position or results of operations may be materially different under changed conditions or when using different estimates and assumptions, particularly with respect to significant accounting policies. If estimates or assumptions differ from actual results, subsequent periods are adjusted to reflect more current information.

Accounting Policies

There have been no material changes in our significant accounting policies during the three months ended September 26, 2015 compared to the significant accounting policies described in our Annual Report on Form 10-K/A for the fiscal year ended June 27, 2015. The accompanying unaudited interim consolidated financial statements and accompanying related notes should be read in conjunction with the consolidated financial statements and related notes included in our Annual Report on Form 10-K/A for the fiscal year ended June 27, 2015.