Lumentum (LITE) 10-Q 1 Nov 18 2019 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares shares in Millions	3 Months Ended
	Sep. 29, 2018	Oct. 26, 2018
Document and Entity Information
Entity Registrant Name	Lumentum Holdings Inc.
Entity Central Index Key	1,633,978
Document Type	10-Q
Document Period End Date	Sep. 29, 2018
Amendment Flag	false
Current Fiscal Year End Date	--06-29
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		63.4
Document Fiscal Year Focus	2,019
Document Fiscal Period Focus	Q1

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions		3 Months Ended
		Sep. 29, 2018	Sep. 30, 2017
Income Statement [Abstract]
Net revenue		$ 354.1	$ 243.2
Cost of sales		227.3	173.9
Amortization of acquired developed technologies		0.8	0.8
Gross profit		126	68.5
Operating expenses:
Research and development		34.6	36.3
Selling, general and administrative		33	26.6
Restructuring and related charges		1.3	2.9
Total operating expenses		68.9	65.8
Income from operations		57.1	2.7
Unrealized gain (loss) on derivative liability		(2.1)	4.2
Interest and other income (expense), net		(2.4)	(3.4)
Income before income taxes		52.6	3.5
Provision for (benefit from) income taxes		5.2	(3.6)
Net income		47.4	7.1
Items reconciling net income to net income attributable to common stockholders:
Cumulative dividends on Series A Preferred Stock		(0.2)	(0.2)
Earnings allocated to Series A Preferred Stock		(1.1)	(0.2)
Net income attributable to common stockholders - Basic		46.1	6.7
Add: Earnings allocated to Series A Preferred Stock		0	0.2
Add/Less: Unrealized (gain) loss on derivative liability on Series A Preferred Stock		0	(4.2)
Add: Cumulative dividends on Series A Preferred Stock		0	0.2
Net income attributable to common stockholders - Diluted	[1]	$ 46.1	$ 2.9
Net income per share attributable to common stockholders:
Basic (usd per share)		$ 0.73	$ 0.11
Diluted (usd per share)		$ 0.72	$ 0.04
Shares used to compute net income per share attributable to common stockholders:
Basic (in shares)		63.1	61.7
Diluted (in shares)		63.9	64.5
[1]	(a) For the three months ended September 30, 2017, our diluted earnings per share attributable to common stockholders is calculated using the if-converted method because it is more dilutive, whereas for the three months ended September 29, 2018, our diluted earnings per share attributable to common stockholders is calculated using the treasury stock method.

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 47.4	$ 7.1
Other comprehensive income (loss), net of tax:
Net change in cumulative translation adjustment	0.1	1.9
Net change in unrealized gain (loss) on available-for-sale securities	0.4	(0.1)
Other comprehensive income, net of tax	0.5	1.8
Comprehensive income (loss), net of tax	$ 47.9	$ 8.9

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Current assets:
Cash and cash equivalents	$ 459.4	$ 397.3
Short-term investments	274.9	314.2
Accounts receivable, net	239.6	197.1
Inventories	136.6	153.6
Prepayments and other current assets	70.6	65
Total current assets	1,181.1	1,127.2
Property, plant and equipment, net	318.6	306.9
Goodwill and intangibles, net	17.6	18.3
Deferred income taxes	122	125.6
Other non-current assets	5.7	3.5
Total assets	1,645	1,581.5
Current liabilities:
Accounts payable	127.6	126.5
Accrued payroll and related expenses	30.3	31.5
Accrued expenses	35	33.9
Other current liabilities	21	22.1
Total current liabilities	213.9	214
Convertible notes	338.5	334.2
Derivative liability	54.5	52.4
Other non-current liabilities	18.8	19
Total liabilities	625.7	619.6
Commitments and contingencies (Note 16)
Redeemable convertible preferred stock:
Total redeemable convertible preferred stock	35.8	35.8
Stockholders’ equity:
Common stock, $0.001 par value, 990,000,000 authorized shares, 63,346,678 and 62,790,087 shares issued and outstanding as of September 29, 2018 and June 30, 2018, respectively	0.1	0.1
Additional paid-in capital	763.5	753.2
Retained earnings	213	166.4
Accumulated other comprehensive income	6.9	6.4
Total stockholders’ equity	983.5	926.1
Total liabilities, redeemable convertible preferred stock, and stockholders’ equity	1,645	1,581.5
Convertible Series A Preferred Stock
Redeemable convertible preferred stock:
Non-controlling interest redeemable convertible Series A Preferred Stock, $0.001 par value, 10,000,000 authorized shares; 35,805 shares issued and outstanding as of September 29, 2018 and June 30, 2018	35.8	$ 35.8
Total redeemable convertible preferred stock	$ 35.8

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 29, 2018	Jun. 30, 2018
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, authorized shares	990,000,000	990,000,000
Common stock, shares issued	63,346,678	62,790,087
Common stock, shares outstanding	63,346,678	62,790,087
Convertible Series A Preferred Stock
Non-controlling interest, preferred stock, par value (usd per share)	$ 0.001	$ 0.001
Non-controlling interest, preferred stock, authorized shares	10,000,000	10,000,000
Non-controlling interest, preferred stock, shares issued	35,805	35,805
Non-controlling interest, preferred stock, shares outstanding	35,805	35,805

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
OPERATING ACTIVITIES:
Net income	$ 47.4	$ 7.1
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	19.7	16.7
Stock-based compensation	10.8	9.3
Unrealized (gain) loss on derivative liability	2.1	(4.2)
Amortization of acquired developed technologies	0.8	0.8
Amortization of discount on 0.25% Convertible Senior Notes due 2024	4.3	4.1
Other non-cash (income) expenses	0	0.1
Changes in operating assets and liabilities:
Accounts receivable	(41.9)	(7.5)
Inventories	15.3	(2)
Prepayments and other current and non-currents assets	(5.3)	(5.8)
Income taxes, net	4.8	(3.5)
Accounts payable	4.1	(1.8)
Accrued payroll and related expenses	(1.1)	(2.4)
Accrued expenses and other current and non-current liabilities	(3.8)	(1.2)
Net cash provided by operating activities	57.2	9.7
INVESTING ACTIVITIES:
Payments for acquisition of property, plant and equipment	(29.6)	(33)
Payment for asset acquisition	(0.7)	0
Purchases of short-term investments	(5.9)	(228.3)
Proceeds from maturities and sales of short-term investments	45.7	128.8
Net cash provided by (used in) investing activities	9.5	(132.5)
FINANCING ACTIVITIES:
Payment of dividends - Series A Preferred Stock	(0.4)	(0.2)
Payment of debt issuance costs	(0.9)	0
Payment of acquisition related holdback	(1)	0
Repayment of capital lease obligation	(2.3)	(1.2)
Proceeds from the exercise of stock options	0	1.7
Net cash provided by (used in) financing activities	(4.6)	0.3
Effect of exchange rates on cash and cash equivalents	0	0.4
Increase (decrease) in cash and cash equivalents	62.1	(122.1)
Cash and cash equivalents at beginning of period	397.3	272.9
Cash and cash equivalents at end of period	459.4	150.8
Supplemental disclosure of cash flow information:
Cash paid for taxes	0.3	0.3
Cash paid for interest	0.6	0.6
Unpaid property, plant and equipment in accounts payable and accrued expenses	18.8	12.6
Equipment acquired under capital lease	$ 0	$ 8.5

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	Sep. 29, 2018	Mar. 31, 2017
Convertible Debt | Convertible Senior Notes Due 2024
Debt, stated interest rate	0.25%	0.25%

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	3 Months Ended
	Sep. 29, 2018
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 (we, us, our or the Company) is an industry-leading provider of optical and photonic products defined by revenue and market share addressing a range of end market applications including OpComms and Lasers for manufacturing, inspection and life-science applications. We seek to use our core optical and photonic technology and our volume manufacturing capability to expand into attractive emerging markets that benefit from advantages that optical or photonics based solutions provide, including 3D sensing for consumer electronics and diode light sources for a variety of consumer and industrial applications. The majority of our customers tend to be OEMs that incorporate our products into their products which then address end-market applications. For example, we sell fiber optic components that Network Equipment Manufacturers (“NEMs”) customers assemble into communications networking systems, which they sell to network service providers or enterprises with their own networks. Similarly, many of our customers for our Lasers products incorporate our products into tools they produce, which are used for manufacturing processes by their customers. For 3D sensing, we sell diode lasers to manufacturers of consumer electronics products for mobile, personal computing, and gaming who then integrate our devices within their products, for eventual resale to consumers and also into other industrial applications. Basis of Presentation The preparation of the condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) 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 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 inventory valuation, revenue recognition, income taxes, long-lived asset valuation, warranty, derivative liability, business combinations, and goodwill. On March 11, 2018, we entered into an Agreement and Plan of Merger (the “Merger Agreement”) with Oclaro, Prota Merger Sub, Inc., and Prota Merger, LLC, pursuant to which we will acquire Oclaro and Oclaro will become a wholly-owned subsidiary of Lumentum. In accordance with the terms of the Merger Agreement, each issued and outstanding share of Oclaro common stock will be exchanged for $5.60 in cash and 0.0636 of a share of Lumentum common stock, subject to the conditions and restrictions set forth in the Merger Agreement. The total transaction consideration was approximately $1.8 billion as of the date of the Merger Agreement. Oclaro stockholders are expected to own approximately 16% of the combined company following the closing. Oclaro’s stockholders approved the Merger Agreement on July 10, 2018 and we have received approval for the transaction under the Hart-Scott Rodino Act in the United States. We are in the process of obtaining antitrust approval in China. The Merger Agreement contains certain termination rights for both Lumentum and Oclaro. The Merger Agreement further provides that upon termination of the Merger Agreement under specified circumstances relating to failure to obtain regulatory approvals by March 11, 2019, Lumentum may be required to pay Oclaro a termination fee of $80 million . In connection with the Merger Agreement, Lumentum entered into a commitment letter, dated as of March 11, 2018, with Deutsche Bank Securities Inc. and Deutsche Bank AG New York Branch (“Deutsche Bank”), pursuant to which, subject to the terms and conditions set forth therein, Deutsche Bank has committed to provide a senior secured term loan facility in an aggregate principal amount of up to $550 million . As of October 26, 2018, the total transaction consideration was expected to be approximately $1.6 billion , which would be funded by a combination of $600 million in Lumentum common stock, $500 million in new debt, and the remaining amount from the cash balances of the combined company. Our commitment letter and related documentation with Deutsche Bank requires payment of a ticking fee to Deutsche Bank. The ticking fee accrues at a rate of (a) commencing on the 31st day following the date on which the term loans were allocated to members of the lending syndicate (the “Allocation Date”), 1.25% per annum, and (b) commencing on the 61st day following the Allocation Date, 2.5% per annum, in each case, based on an aggregate principal amount of term loan commitments provided by Deutsche Bank under the commitment letter. The Allocation Date occurred on August 8, 2018 and, as of September 29, 2018, we had not borrowed any funds under the senior secured term loan facility. Accordingly, we began to incur ticking fees on the $500 million of term loan commitments on September 8, 2018. We expensed $0.4 million related to the ticking fee, which is included in interest expense in our condensed consolidated statements of operations for the three months ended September 29, 2018. During the three months ended September 29, 2018, we also incurred $0.9 million of debt issuance costs in connection with the above facility which were capitalized and recorded in other non-current assets on our condensed consolidated balance sheet. These costs will be recorded as contra liability when the debt is drawn and will be amortized to interest expense using the effective interest rate method from the issuance date through the end of the term of the loan. The transaction is subject to customary closing conditions, including antitrust regulatory approval in China. The transaction is not subject to any financing condition. Although we anticipate that the transaction will be be completed by December 11, 2018, the termination date of the merger agreement will be automatically extended to March 11, 2019, subject to certain conditions set forth in the Merger Agreement. Fiscal Years We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th. Our fiscal 2019 is a 52-week year ending on June 29, 2019 . Our fiscal 2018 was a 52-week year and ended on June 30, 2018 . Principles of Consolidation These interim unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All inter-company transactions and balances have been eliminated in consolidation. Certain prior period amounts have been reclassified to conform to the current year presentation on the notes to condensed consolidated financial statements. The reclassification of the prior period amounts did not impact previously reported condensed consolidated financial statements. Accounting Policies The accompanying interim unaudited condensed consolidated financial statements and accompanying related notes should be read in conjunction with the audited consolidated financial statements and related notes included in our Annual Report on Form 10-K for the fiscal year ended June 30, 2018 . Except for the accounting policies for revenue recognition and adoption of Accounting Standard Update (“ASU”) 2014-09, Revenue from Contracts with Customers (Topic 606) , there have been no significant changes to our significant accounting policies as of and for the three months ended September 29, 2018 , as compared to the significant accounting policies described in our Annual Report on Form 10-K for the year ended June 30, 2018 . Adoption of Topic 606 Revenue Recognition Policy Pursuant to Topic 606, our revenues are recognized upon the application of the following steps: • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract; • determination of the transaction price; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenues when, or as, the contractual performance obligations are satisfied The majority of our revenue comes from product sales, consisting of sales of Lasers and OpComms hardware products to our customers. Our revenue contracts generally include only one performance obligation. Revenues are recognized at a point in time when control of the promised goods or services is transferred to our customers upon shipment or delivery, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. We have entered into vendor managed inventory (“VMI”) programs with our customers. Under these arrangements, we receive purchase orders from our customers, and the inventory is shipped to the VMI location upon receipt of the purchase order. The customer then pulls the inventory from the VMI hub based on its production needs. Revenue under VMI programs is recognized when control transfers to the customer, which is generally upon pull of inventory by the customer from the hub. Revenue from all sales types is recognized at transaction price. The transaction price is determined based on the consideration to which we will be entitled in exchange for transferring goods or services to the customer adjusted for estimated variable consideration, if any. We typically estimate the transaction price impact of discounts offered to the customers for early payments on receivables or net of accruals for estimated sales returns. These estimates are based on historical returns, analysis of credit memo data and other known factors. Actual returns could differ from these estimates. We allocate the transaction price to each distinct product based on its relative standalone selling price. The product price as specified on the purchase order is considered the standalone selling price as it is an observable input that depicts the price as if sold to a similar customer in similar circumstances. Taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction, that are collected by us from a customer and deposited with the relevant government authority, are excluded from revenue. Our revenue arrangements do not contain significant financing components as our standard payment terms are less than one year. If a customer pays consideration, or Lumentum has a right to an amount of consideration that is unconditional before we transfer a good or service to the customer, those amounts are classified as deferred income/advances received from customers which are included in other current liabilities or other long-term liabilities when the payment is made or it is due, whichever is earlier. Transaction Price Allocated to the Remaining Performance Obligations Remaining performance obligations represent the transaction price allocated to performances obligations that are unsatisfied or partially unsatisfied as of the end of the reporting period. Unsatisfied and partially unsatisfied performance obligations consist of contract liabilities and non-cancellable backlog. Non-cancellable backlog includes goods and services for which customer purchase orders have been accepted that are scheduled or in the process of being scheduled for shipment. The following table includes estimated revenue expected to be recognized in the future for backlog related performance obligations that are unsatisfied (or partially unsatisfied) as of September 29, 2018 : Less than 1 year 1-2 years Greater than 2 years Total Performance Obligations $384.8 $22.7 $0.4 $407.9 Warranty Hardware products regularly include warranties to the end customers such that the product continues to function according to published specifications. We typically offer a twelve month warranty for most of our products. However, in some instances depending upon the product, specific market, product line and geography we deal in, and what is common in the industry, our warranties can vary and range from six months to five years . These standard warranties are assurance type warranties and do not offer any services in addition to the assurance that the product will continue working as specified. Therefore, warranties are not considered separate performance obligations in the arrangement. Instead, the expected cost of warranty is accrued as expense in accordance with authoritative guidance. We provide reserves for the estimated costs of product warranties at the time revenue is recognized. We estimate the costs of our warranty obligations based on our historical experience of known product failure rates, use of materials to repair or replace defective products and service delivery costs incurred in correcting product failures. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise. Shipping and Handling Costs We record shipping and handling costs related to revenue transactions within cost of sales as a period cost. Contract Costs The Company recognizes the incremental direct costs of obtaining a contract, which consist of sales commissions, when control over the products they relate to transfers to the customer. Applying the practical expedient, the Company recognizes commissions as expense when incurred, as the amortization period of the commission asset the Company would have otherwise recognized is less than one year. Contract Balances The Company records accounts receivable when it has an unconditional right to consideration. Contract liabilities are recorded when cash payments are received or due in advance of performance. Contract liabilities consist of advance payments and deferred revenue, where the Company has unsatisfied performance obligations. Contract liabilities are classified as deferred revenue and customer deposits and included in other current liabilities of our condensed consolidated balance sheet. Payment terms vary by customer. The time between invoicing and when payment is due is not significant. The following table reflects the changes in contract balances for the three months ended September 30, 2018: Contract balances Balance sheet location September 29, 2018 June 30, 2018 Change Percentage Change Accounts receivable, net Accounts receivable, net $239.6 $197.1 $42.5 21.6% Deferred revenue and customer deposits Other current liabilities $2.6 $2.8 $(0.2) (7.1)% During the three months ended September 29, 2018 , deferred revenue and customer deposits decreased primarily due to revenue recognized for the satisfaction of performance obligation over time in the amount of $0.4 million . Disaggregation of Revenue We disaggregate revenue by geography and by product, no other level of disaggregation is required considering the type of products, customer, markets, contracts, duration of contracts, timing of transfer of control and sales channels, based on the information that our chief operating decision maker uses to manage the business.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	3 Months Ended
	Sep. 29, 2018
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Note 2. Recently Issued Accounting Pronouncements Accounting Pronouncements Recently Adopted In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-09 (Topic 606), which amended the existing accounting standards for revenue recognition. Topic 606 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The guidance is effective for annual reporting periods including interim reporting periods beginning after December 15, 2017. On July 1, 2018, we adopted Topic 606 using the modified retrospective method applied to all contracts that are not completed contracts at the date of initial adoption (i.e., July 1, 2018). Results for reporting periods after July 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under Topic 605. The adoption of Topic 606 did not have a material impact on the nature and timing of our revenues, condensed consolidated statements of operations, cash flows, and balance sheet and therefore, we do not present results for the three months ended September 29, 2018 under Topic 605. Refer to “ Note 1. Description of Business and Summary of Significant Accounting Policies ” for the changes in our accounting policies due to adoption of Topic 606. Select condensed consolidated balance sheet line items, as if we had adopted Topic 606 in previous years, are summarized below as of the periods presented: June 30, 2018 Adjustments July 1, 2018 Assets: Accounts receivable, net $ 197.1 $ 0.6 $ 197.7 Inventories 153.6 (1.2 ) 152.4 Stockholders’ equity: Retained earnings $ 166.4 $ (0.6 ) $ 165.8 In August 2016, FASB issued ASU 2016-15, S tatement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which clarifies how companies present and classify certain cash receipts and cash payments in the statement of cash flows. The amendments contained in ASU 2016-15 are effective for interim and annual periods beginning after December 15, 2017. We adopted ASU 2016-15 on July 1, 2018 on a prospective basis. The application of ASU 2016-15 will have a material impact on our consolidated financial statements if we elect to settle the principal amounts of our 2024 Notes (refer to “ Note 10. Convertible Senior Notes ”) in cash. The principal repayment will be bifurcated between (i) cash outflows for operating activities of $137.6 million for the portion related to accreted interest attributable to debt discount, and (ii) financing activities for the remainder of $312.4 million . In January 2017, FASB issued ASU 2017-01, Business Combinations (Topic 805) , which clarifies the definition of a business. For accounting and financial reporting purposes, businesses are generally comprised of three elements; inputs, processes, and outputs. Integrated sets of assets and activities capable of providing these three elements may not always be considered a business, and the lack of one of the three elements does not always disqualify the set from being a business. The issuance of ASU 2017-01 provides a clarifying screen to determine when a set of assets and activities is not a business. Primarily, the screen requires that when substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the set is not a business. The amendments contained in ASU 2017-01 are effective for annual periods beginning after December 15, 2017, including interim periods within those periods. We adopted ASU 2017-01 on July 1, 2018 on a prospective basis. The implementation of ASU 2017-01 did not have an impact on our financial statements. In October 2016, FASB issued ASU 2016-16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets other than Inventory. The new guidance removes the prohibition in ASC 740 against the immediate recognition of the current and deferred income tax effects of intra-entity transfers of assets other than inventory. The new guidance became effective for us in the first quarter of our fiscal 2019. The adoption of ASU 2016-16 did not have a material impact on our financial statements. Accounting Pronouncements Not Yet Effective In August 2018, the Securities and Exchange Commission (“SEC”) adopted amendments to certain disclosure requirements in Securities Act Release No. 33-10532, Disclosure Update and Simplification . The amendments will become effective on November 5, 2018. The SEC staff subsequently indicated that it would not object if a filer’s first presentation of changes in shareholders’ equity is included in its Form 10-Q for the quarter that begins after the final rule’s effective date. Among the amendments is the requirement to present the changes in shareholders’ equity in the interim financial statements (either in a separate statement or footnote) in quarterly reports on Form 10-Q. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a consolidated statement of operations is required to be filed. We will include the first presentation of changes in stockholders’ equity on Form 10-Q in our third quarter of fiscal 2019. In August 2018, FASB issued ASU 2018-15, Intangibles-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. ASU 2018-15 requires an entity in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which implementation costs to capitalize as an asset related to the service contract and which costs to expense. Implementation costs capitalized must be expensed over the term of the hosting arrangement, including the period covered by an option to extend the arrangement. The standard is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, and should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. Early adoption is permitted, including adoption in any interim period, for all entities. ASU 2018-15 is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of ASU 2018-15 on our consolidated financial statements. In August 2018, FASB issued ASU 2018-14, Compensation-Retirement Benefits-Defined Benefit Plans-General (Topic 715-20): Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans . ASU 2018-14 modifies the disclosure requirements for defined benefit pension plans and other postretirement benefit plans. The new guidance is effective for fiscal years ending after December 15, 2020 and early adoption is permitted. ASU 2018-14 should be applied retrospectively to all periods presented and is effective for us in our first quarter of fiscal 2022. We are currently evaluating the impact of ASU 2018-14 on our consolidated financial statements. In August 2018, FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 modifies the disclosure requirements for fair value measurements. The new guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Entities are permitted to early adopt any removed or modified disclosures upon issuance of ASU 2018-13 and delay adoption of the additional disclosures until the effective date. The standard is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of ASU 2018-13 on our consolidated financial statements and related disclosures. In February 2018, FASB issued ASU 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which allows companies to reclassify stranded tax effects resulting from the Tax Act, from accumulated other comprehensive income to retained earnings. The guidance also requires certain new disclosures regardless of the election. The amendments in ASU 2018-02 are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. ASU 2018-02 is effective for us in the first quarter of fiscal 2020. We are currently evaluating the impact of our pending adoption of ASU 2018-02 on our consolidated financial statements. In January 2017, FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment . ASU 2017-04 removes the requirement to perform a hypothetical purchase price allocation to measure goodwill impairment. A goodwill impairment charge will be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The amendments contained in ASU 2017-04 are effective for interim and annual periods beginning after December 15, 2019, with early adoption permitted, which should be applied prospectively. We plan to adopt the accounting standard update in our first quarter of fiscal 2020. We are currently evaluating the impact of ASU 2017-04 on our consolidated financial statements. In February 2016, FASB issued ASU 2016-02, Leases . The new guidance generally requires an entity to recognize on its balance sheet operating and financing lease liabilities and corresponding right-of-use assets. The new guidance contained in ASU 2016-02 is effective for annual periods beginning after December 15, 2018, including interim periods within those periods, with early adoption permitted. The standard is effective for us in our first quarter of fiscal 2020 where we will be required to recognize and measure leases existing at, or entered into after, the beginning of the earliest comparative period presented using a modified retrospective approach, with an option to elect certain practical expedients. Based on our current lease portfolio, we estimate the value of leased assets and liabilities that may be recognized will be material. We are continuing to evaluate the impact of ASU 2016-02 which is subject to change.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Sep. 29, 2018
Earnings Per Share [Abstract]
Earnings Per Share	Note 3. Earnings Per Share The following table sets forth the computation of basic and diluted net income attributable to common stockholders per share ( in millions, except per share data ): Three Months Ended September 29, 2018 September 30, 2017 Basic Earnings per Common Share Net income $ 47.4 $ 7.1 Less: Cumulative dividends on Series A Preferred Stock (0.2 ) (0.2 ) Less: Earnings allocated to Series A Preferred Stock (1.1 ) (0.2 ) Net income attributable to common stockholders - Basic $ 46.1 $ 6.7 Weighted average common shares outstanding including Series A Preferred Stock 64.6 63.2 Less: Weighted average Series A Preferred Stock (1.5 ) (1.5 ) Basic weighted average common shares outstanding 63.1 61.7 Net income per share attributable to common stockholders - Basic $ 0.73 $ 0.11 Diluted Earnings per Common Share Net income attributable to common stockholders - Basic $ 46.1 $ 6.7 Add: Earnings allocated to Series A Preferred Stock — 0.2 Add/Less: Unrealized (gain) loss on derivative liability on Series A Preferred Stock — (4.2 ) Add: Cumulative dividends on Series A Preferred Stock — 0.2 Net income attributable to common stockholders - Diluted (a) $ 46.1 $ 2.9 Weighted average common shares outstanding for basic earnings per common share 63.1 61.7 Effect of dilutive securities from 2015 Equity Incentive Plan 0.8 1.3 Effect of dilutive securities from Series A Preferred Stock — 1.5 Diluted weighted average common shares outstanding 63.9 64.5 Net income per share attributable to common stockholders - Diluted $ 0.72 $ 0.04 (a) For the three months ended September 30, 2017, our diluted earnings per share attributable to common stockholders is calculated using the if-converted method because it is more dilutive, whereas for the three months ended September 29, 2018, our diluted earnings per share attributable to common stockholders is calculated using the treasury stock method. Our Series A Preferred Stock is considered a participating security, which may participate in undistributed earnings with our common stock. The holders of our Preferred Stock would be entitled to share in dividends, on an as-converted basis, if the holders of our common stock were to receive dividends. We are required to use the two-class method when computing earnings per share as we have a security that qualifies as a participating security. The two-class method is an earnings allocation formula that determines earnings per share for each class of common stock and participating security according to dividends declared (or accumulated) and participation rights in undistributed earnings. In determining the amount of net earnings to allocate to common stockholders, earnings are allocated to both common and participating securities based on their respective weighted-average shares outstanding during the period. Under the two-class method, basic earnings per common share is calculated by dividing the net income (loss) attributable to common stockholders by the weighted-average number of shares of common stock outstanding for the period. The diluted earnings per common share is calculated similarly to basic earnings per common share except that it gives effect to all potentially dilutive common stock equivalents outstanding for the period using the treasury stock method. Diluted earnings per common share, when applicable, is computed using the more dilutive of the treasury stock method or the if-converted method. In periods of net loss, no effect is given to participating securities since they do not contractually participate in the losses of the Company. In March 2017, we issued $450 million in aggregate principal amount of 0.25% Convertible Senior Notes due in 2024 (the “2024 Notes”). We have the ability and intent to settle the $450 million face value of the 2024 Notes in cash. Therefore, we use the treasury stock method for calculating the dilutive impact of the 2024 Notes. The 2024 Notes will have no impact to diluted earnings per share until the average price of our common stock exceeds the conversion price of $60.62 . Refer to “ Note 10. Convertible Senior Notes ” for further discussion. The dilutive effect of securities from the 2015 Equity Incentive Plan is reflected in diluted earnings per share by application of the treasury stock method, which includes consideration of unamortized share-based compensation expense and the dilutive effect of in-the-money options and non-vested restricted stock units. Under the treasury stock method, the amount the employee must pay for exercising stock options and the amount of unamortized share-based compensation expense are collectively assumed to be used to repurchase hypothetical shares. An increase in the fair value of our common stock can result in a greater dilutive effect from potentially dilutive awards. Anti-dilutive potential shares from 2015 Equity Incentive Plan are excluded from the calculation of diluted earnings per share if their exercise price exceeded the average market price during the period or the share-based awards were determined to be anti-dilutive based on applying the treasury stock method.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Sep. 29, 2018
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Note 4. Accumulated Other Comprehensive Income (Loss) Our accumulated other comprehensive income (loss) consists of the accumulated net unrealized gains or losses on foreign currency translation adjustments, the defined benefit obligation, and available-for-sale securities. As of September 29, 2018 and June 30, 2018 , balances for the components of accumulated other comprehensive income (loss) were as follows ( in millions ): Foreign currency translation adjustments, net of tax Defined benefit obligation, net of tax (1) Unrealized gain (loss) on available-for-sale securities, net of tax Total Beginning balance as of June 30, 2018 $ 10.3 $ (2.3 ) $ (1.6 ) $ 6.4 Other comprehensive income 0.1 — 0.4 0.5 Ending balance as of September 29, 2018 $ 10.4 $ (2.3 ) $ (1.2 ) $ 6.9 (1) We evaluate the assumptions over the fair value of our defined benefit obligation annually and make changes as necessary.

Asset Acquisition

Asset Acquisition	3 Months Ended
	Sep. 29, 2018
Asset Acquisition [Abstract]
Asset Acquisition	Note 5. Asset Acquisition On March 30, 2018, we entered into a Transition Services Agreement (“TSA”) with one of our contract manufacturers to wind down the production of our products at their facility in China and to facilitate an orderly transition of manufacturing to either our manufacturing facility in Thailand or our third party contract manufacturers, including the purchase of the manufacturing equipment. Under the terms of the TSA, we are required to pay $5.3 million in cash upon completion of certain milestones related to the purchase of equipment. During the three months ended September 29, 2018 , we paid $0.7 million for the manufacturing equipment acquired under this TSA. This amount is included in construction in progress on our condensed consolidated balance sheet as of September 29, 2018 . We are also required to share cost of retention and severance, and to reimburse for certain other direct and indirect costs incurred by our contract manufacturer for transition services provided. These costs will be expensed as incurred.

Balance Sheet Details

Balance Sheet Details	3 Months Ended
	Sep. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Details	Note 6. Balance Sheet Details Accounts receivable allowances As of September 29, 2018 and June 30, 2018 , our accounts receivable allowance balance was $ 2.1 million and $2.6 million , respectively. Inventories The components of inventories were as follows ( in millions ): September 29, 2018 June 30, 2018 Finished goods $ 80.7 $ 98.2 Work in process 32.9 34.5 Raw materials and purchased parts 23.0 20.9 Inventories $ 136.6 $ 153.6 Prepayments and other current assets The components of prepayments and other current assets were as follows ( in millions ): September 29, 2018 June 30, 2018 Capitalized manufacturing overhead $ 18.3 $ 20.5 Prepayments 22.3 19.5 Advances to contract manufacturers 13.7 14.0 Other current assets 16.3 11.0 Prepayments and other current assets $ 70.6 $ 65.0 Property , plant and equipment, net The components of property, plant and equipment, net were as follows ( in millions ): September 29, 2018 June 30, 2018 Land $ 10.6 $ 10.6 Buildings and improvement 59.4 55.1 Machinery and equipment (1) 476.0 463.6 Computer equipment and software 26.5 26.3 Furniture and fixtures 2.9 2.2 Leasehold improvements 27.0 25.8 Construction in progress 59.9 52.6 662.3 636.2 Less: Accumulated depreciation (343.7 ) (329.3 ) Property, plant and equipment, net $ 318.6 $ 306.9 (1) In fiscal 2018, we started leasing equipment from a vendor and have accounted for the transaction as a capital lease. Included in the table above is our capital lease asset of $15.6 million , gross and depreciation expense of $6.7 million as of September 29, 2018 . During the three months ended September 29, 2018 and September 30, 2017 , we recorded depreciation expense of $19.7 million and $16.7 million , respectively. Our construction in progress primarily includes machinery and equipment that were purchased in order to increase our manufacturing capacity. We expect to place these assets in service in the next 12 months. Other current liabilities The components of other current liabilities were as follows (in millions) : September 29, 2018 June 30, 2018 Warranty accrual (1) $ 6.6 $ 6.6 Restructuring accrual and related charges (2) 1.6 1.9 Deferred revenue and customer deposits 2.6 2.8 Capital lease obligation (3) 5.4 7.3 Other current liabilities 4.8 3.5 Other current liabilities $ 21.0 $ 22.1 (1) Refer to “ Note 16. Commitments and Contingencies ” in the Notes to Unaudited Condensed Consolidated Financial Statements. (2) Refer to “ Note 13. Restructuring and Related Charges ” in the Notes to Unaudited Condensed Consolidated Financial Statements. (3) As of September 29, 2018 , an amount of $1.6 million related to a capital lease was recorded in accounts payable on the condensed consolidated balance sheet. Refer to “ Note 16. Commitments and Contingencies ” in the Notes to Unaudited Condensed Consolidated Financial Statements. Other non-current liabilities The components of other non-current liabilities were as follows ( in millions ): September 29, 2018 June 30, 2018 Asset retirement obligation $ 2.7 $ 2.7 Pension and related accrual 3.7 3.5 Deferred rent 2.5 2.6 Unrecognized tax benefit 9.0 6.1 Capital lease obligation (1) — 0.4 Other non-current liabilities 0.9 3.7 Other non-current liabilities $ 18.8 $ 19.0 (1) Refer to “ Note 16. Commitments and Contingencies ” in the Notes to Unaudited Condensed Consolidated Financial Statements.

Cash, Cash Equivalents, and Sho

Cash, Cash Equivalents, and Short-term Investments	3 Months Ended
	Sep. 29, 2018
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents, and Short-term Investments	Note 7. Cash, Cash Equivalents, and Short-term Investments Cash, cash equivalents and short-term investments The following table summarizes our cash, cash equivalents, and short-term investments by category for the periods presented ( in millions ): Amortized Gross Gross Fair Value September 29, 2018: Cash $ 149.9 $ — $ — $ 149.9 Cash equivalents: Commercial paper 3.6 — — 3.6 Money market funds 286.5 — — 286.5 U.S. Treasury 19.4 — — 19.4 Total cash and cash equivalents $ 459.4 $ — $ — $ 459.4 Short-term investments: Commercial paper $ 6.7 $ — $ — $ 6.7 Asset-backed securities 58.5 — (0.2 ) 58.3 Corporate debt securities 202.4 0.1 (1.1 ) 201.4 Municipal bonds 0.4 — — 0.4 Mortgage-backed securities 3.0 — — 3.0 Foreign government bonds 5.1 — — 5.1 Total short-term investments $ 276.1 $ 0.1 $ (1.3 ) $ 274.9 June 30, 2018: Cash $ 103.6 $ — $ — $ 103.6 Cash equivalents: Certificates of deposit 3.0 — — 3.0 Commercial paper 112.1 — — 112.1 Money market funds 0.8 — — 0.8 U.S. Treasury securities 143.6 — — 143.6 U.S. Agency securities 34.2 — — 34.2 Total cash and cash equivalents $ 397.3 $ — $ — $ 397.3 Short-term investments: Certificates of deposit $ 7.5 $ — $ — $ 7.5 Commercial paper 10.5 — — 10.5 Asset-backed securities 68.0 — (0.2 ) 67.8 Corporate debt securities 220.6 0.1 (1.5 ) 219.2 Municipal bonds 1.6 — — 1.6 Mortgage-backed securities 4.2 — — 4.2 Foreign government bonds 3.4 — — 3.4 Total short-term investments $ 315.8 $ 0.1 $ (1.7 ) $ 314.2 We use the specific-identification method to determine any realized gains or losses from the sale of our short-term investments classified as available-for-sale. During the three months ended September 29, 2018 and September 30, 2017 , we did not realize significant gains or losses on a gross level from the sale of our short-term investments classified as available-for-sale. During the three months ended September 29, 2018 and September 30, 2017 , our interest and other income (expense), net of $(2.4) million and $(3.4) million , includes interest income on the short-term investments and cash equivalents of $2.7 million and $1.5 million , respectively. The following table summarizes unrealized losses on our cash equivalents and short-term investments by category and length of time the investment has been in a continuous unrealized loss position as of the periods presented (in millions) : Less than 12 months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses September 29, 2018: Commercial paper $ 6.1 $ — $ — $ — $ 6.1 $ — Asset-backed securities 48.4 (0.2 ) 8.5 — 56.9 (0.2 ) Corporate debt securities 113.3 (0.8 ) 46.9 (0.3 ) 160.2 (1.1 ) Mortgage-backed securities 2.8 — — — 2.8 — Foreign government bonds 4.1 — — — 4.1 — Total $ 174.7 $ (1.0 ) $ 55.4 $ (0.3 ) $ 230.1 $ (1.3 ) June 30, 2018: Certificates of deposit $ 5.4 $ — $ — $ — $ 5.4 $ — Commercial paper 8.5 — — — 8.5 — Asset-backed securities 66.6 (0.2 ) 0.3 — 66.9 (0.2 ) Corporate debt securities 188.6 (1.5 ) 2.0 — 190.6 (1.5 ) Municipal bonds 0.6 — — — 0.6 — U.S. Agency securities 4.0 — — — 4.0 — Foreign government bonds 3.4 — — — 3.4 — Total $ 277.1 $ (1.7 ) $ 2.3 $ — $ 279.4 $ (1.7 ) The following table classifies our investments in debt securities by contractual maturities ( in millions ): September 29, 2018 June 30, 2018 Amortized Cost Fair Value Amortized Cost Fair Value Due in 1 year $ 150.0 $ 149.5 $ 150.1 $ 149.6 Due in 1 year through 5 years 119.4 118.7 157.2 156.1 Due in 5 years through 10 years 4.9 4.9 6.1 6.1 Due after 10 years 1.8 1.8 2.4 2.4 $ 276.1 $ 274.9 $ 315.8 $ 314.2 All available-for-sale securities have been classified as current, based on management’s intent and ability to use the funds in current operations.

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Sep. 29, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 8. Fair Value Measurements We determine fair value based on the fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value assumes that the transaction to sell the asset or transfer the liability occurs in the principal or most advantageous market for the asset or liability and establishes that the fair value of an asset or liability shall be determined based on the assumptions that market participants would use in pricing the asset or liability. The classification of a financial asset or liability within the hierarchy is based upon the lowest level input that is significant to the fair value measurement. The fair value hierarchy prioritizes the inputs into three levels that may be used to measure fair value: Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2: Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3: Inputs are unobservable inputs based on our assumptions. The fair value of the Company’s Level 1 financial instruments, such as money market funds, which are traded in active markets, is based on quoted market prices for identical instruments. The fair value of the Company’s Level 2 fixed income securities is obtained from an independent pricing service, which may use quoted market prices for identical or comparable instruments or model driven valuations using observable market data or inputs corroborated by observable market data. Our marketable securities are held by custodians who obtain investment prices from a third-party pricing provider that incorporates standard inputs in various asset price models. The Company’s procedures include controls to ensure that appropriate fair values are recorded, including comparing the fair values obtained from the Company’s pricing service against fair values obtained from another independent source. We estimate the fair value of the embedded derivative for the Series A Preferred Stock using the binomial lattice model. The lattice model requires the various assumptions to be made to determine the fair value of the embedded derivatives. These assumptions represent Level 3 inputs. Refer to “ Note 11. Derivative Liability ” in the Notes to Unaudited Condensed Consolidated Financial Statements. In February 2017, we completed the acquisition of a privately held company to enhance our manufacturing and vertical integration capabilities for a total purchase consideration of $8.7 million . We estimated the fair value of our Level 3 contingent consideration related to this acquisition at the present value of the expected contingent payments, determined using a probabilistic approach. We are required to reassess the fair value of contingent payments on a periodic basis. We estimated the likelihood of meeting the production targets at 90 percent and recorded the fair value of such contingent consideration in other current liabilities on the condensed consolidated balance sheet as of September 29, 2018 . This contingent consideration will result in a cash payment of $3.0 million , if and when the production targets are achieved, which we expect to occur within the following 12 months . There was no change in the fair value of our contingent consideration during the three months ended September 29, 2018 and September 30, 2017 . Our pension assets consist of multiple institutional funds (“pension funds”) of which the fair values are based on the quoted prices of the underlying funds. Pension funds are classified as Level 2 assets since such funds are not directly traded in active markets. Financial assets and liabilities measured at fair value on a recurring basis are summarized below ( in millions ): Level 1 Level 2 Level 3 Total September 29, 2018: Assets: Cash equivalents: Commercial paper $ — $ 3.6 $ — $ 3.6 Money market funds 286.5 — — 286.5 U.S. Treasury 19.4 — — 19.4 Short-term investments: Commercial paper — 6.7 — 6.7 Asset-backed securities — 58.3 — 58.3 Corporate debt securities — 201.4 — 201.4 Municipal bonds — 0.4 — 0.4 Mortgage-backed securities — 3.0 — 3.0 Foreign government bonds — 5.1 — 5.1 Total assets $ 305.9 $ 278.5 $ — $ 584.4 Other accrued liabilities: Derivative liability $ — $ — $ 54.5 $ 54.5 Acquisition contingencies — — 2.7 2.7 Total other accrued liabilities $ — $ — $ 57.2 $ 57.2 Level 1 Level 2 Level 3 Total June 30, 2018: Assets: Cash equivalents: Certificates of deposit $ — $ 3.0 $ — $ 3.0 Commercial paper — 112.1 — 112.1 Money market funds 0.8 — — 0.8 U.S. Treasury securities 143.6 — — 143.6 U.S. Agency securities — 34.2 — 34.2 Short-term investments: Certificates of deposit — 7.5 — 7.5 Commercial paper — 10.5 — 10.5 Asset-backed securities — 67.8 — 67.8 Corporate debt securities — 219.2 — 219.2 Municipal bonds — 1.6 — 1.6 Mortgage-backed securities — 4.2 — 4.2 Foreign government bonds — 3.4 — 3.4 Total assets $ 144.4 $ 463.5 $ — $ 607.9 Other accrued liabilities: Derivative liability $ — $ — $ 52.4 $ 52.4 Acquisition contingencies — — 2.7 2.7 Total other accrued liabilities $ — $ — $ 55.1 $ 55.1 Assets Measured at Fair Value on a Non-Recurring Basis We periodically review our intangible and other long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on the lowest level of identifiable estimated undiscounted cash flows resulting from use of the asset and its eventual disposition. If not recoverable, an impairment loss would be calculated based on the excess of the carrying amount over the fair value. Management utilizes various valuation methods, including an income approach, a market approach and a cost approach, to estimate the fair value of intangible and other long-lived assets. During the annual impairment testing performed in fiscal 2018, we concluded that our intangible and other long-lived assets were not impaired. No impairment charges were recorded during the three months ended September 29, 2018 and September 30, 2017 . Refer to “ Note 12. Goodwill and Other Intangible Assets ”.

Non-Controlling Interest Redeem

Non-Controlling Interest Redeemable Convertible Preferred Stock	3 Months Ended
	Sep. 29, 2018
Temporary Equity Disclosure [Abstract]
Non-Controlling Interest Redeemable Convertible Preferred Stock	Note 9. Non-Controlling Interest Redeemable Convertible Preferred Stock On July 31, 2015, our wholly-owned subsidiary, Lumentum Inc., issued 40,000 shares of its Series A Preferred Stock to Viavi Solutions Inc. (“Viavi”). Pursuant to a securities purchase agreement between the Company, Viavi and Amada Holdings Co., Ltd. (“Amada”), 35,805 shares of Series A Preferred Stock were sold by Viavi to Amada in August 2015. The remaining 4,195 shares of the Series A Preferred Stock were canceled. The Series A Preferred Stock is referred to as our Non-Controlling Interest Redeemable Convertible Preferred Stock within these condensed consolidated financial statements. The Series A Preferred Stock is redeemable at the option of Amada after five years and classified as non-controlling interest redeemable convertible preferred stock in our condensed consolidated balance sheet. The Series A Preferred Stock is measured at its redemption value. The Series A Preferred Stock value of $35.8 million as of September 29, 2018 has not changed from the prior year. The Series A Preferred Stock conversion feature is bifurcated from the Series A Preferred Stock and accounted for separately as a derivative liability. The derivative liability is measured at fair value each reporting period with the change in fair value recorded in the condensed consolidated statements of operations. Refer to “ Note 11. Derivative Liability ”. The following paragraphs describe the terms and conditions of the Series A Preferred Stock: Conversion The Series A Preferred Stock is convertible, at the option of the holder, into shares of our common stock commencing on the second anniversary of the closing of the securities purchase in August 2017 (absent a change of control of us or similar event) using a conversion price of $24.63 , which is equal to 125% of the volume weighted average price per share of our common stock in the five “regular-way” trading days following our separation from JDS Uniphase Corporation (“JDSU” and now, Viavi) in August 2015 (the “Separation”). Liquidation Upon any liquidation, dissolution, or winding up of our business, whether voluntary or involuntary, holders of Series A Preferred Stock will be entitled to receive, in preference to holders of common stock or any other class or series of our outstanding capital stock ranking in any such event junior to the Series A Preferred Stock, an amount per share equal to the greater of (i) the Issuance Value of $1,000 per share for Series A Preferred Stock plus all accrued and unpaid dividends thereon (whether or not authorized or declared) through the date of payment and (ii) the amount as would have been payable had all Series A Preferred Stock been converted into common stock immediately prior to such liquidation event. If upon occurrence of any such event, our assets legally available for distribution are insufficient to permit payment of the aforementioned preferential amounts, then all of our assets legally available for distribution will be distributed ratably to the holders of the Series A Preferred Stock and to the holders of any other class or series of our capital stock ranking on parity with the Series A Preferred Stock. Voting Rights The shares of Series A Preferred Stock have no voting rights except as follows: • Authorize, approve, or make any change to the powers, preferences, privileges or rights of the Series A Preferred Stock; • Authorize or issue any additional shares of Series A Preferred Stock or reduce the number of shares of Series A Preferred Stock; or • Create, or hold capital stock in, any subsidiary that is not wholly-owned by the Company. Dividends Holders of Series A Preferred Stock, in preference to holders of common stock or any other class or series of our outstanding capital stock ranking in any such event junior to the Series A Preferred Stock, are entitled to receive, when and as declared by the board of directors, quarterly cumulative cash dividends at the annual rate of 2.5% of the Issuance Value per share on each outstanding share of Series A Preferred Stock. The accrued dividends are payable on March 31, June 30, September 30 and December 31 of each year commencing on September 30, 2015. The accrued dividends as of September 29, 2018 and June 30, 2018 were $0.2 million and $0.4 million , respectively. During the three months ended September 29, 2018 and September 30, 2017 , we paid $0.4 million and $0.2 million , respectively, in dividends to the holders of Series A Preferred Stock. Redemption Optional redemption by the Company On or after the third anniversary, which occurred in August 2018, we have the option upon providing notice of not less than 30 calendar days to redeem for cash all (but not less than all) of the shares of Series A Preferred Stock at a redemption price equal to the Issuance Value plus the accrued and unpaid dividends on each share and any past due dividends, whether or not authorized or declared. On October 15, 2018, we issued a 30 -day notice of intent to the holders of Series A Preferred Stock to redeem all shares of Series A Preferred Stock. We expect the holders of Series A Preferred Stock to exercise their right to convert by November 14, 2018.

Convertible Senior Notes

Convertible Senior Notes	3 Months Ended
	Sep. 29, 2018
Debt Disclosure [Abstract]
Convertible Senior Notes	Note 10. Convertible Senior Notes In March 2017, we issued the 2024 Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under the Securities Act of 1933, as amended (the “Securities Act”). The 2024 Notes are governed by an indenture between the Company, as the issuer, and U.S. Bank National Association, as trustee (the “Indenture”). The 2024 Notes are unsecured and do not contain any financial covenants, restrictions on dividends, incurrence of senior debt or other indebtedness, or the issuance or repurchase of securities by us. The 2024 Notes bear interest at a rate of 0.25% per year. Interest on the 2024 Notes is payable semi-annually in arrears on March 15 and September 15 of each year, beginning on September 15, 2017. The 2024 Notes will mature on March 15, 2024, unless earlier repurchased by us or converted pursuant to their terms. The initial conversion rate of the 2024 Notes is 16.4965 shares of common stock per $1,000 principal amount of 2024 Notes, which is equivalent to an initial conversion price of approximately $60.62 per share, a 132.5% premium to the fair market value at the date of issuance. Prior to the close of business on the business day immediately preceding December 15, 2023, the 2024 Notes will be convertible only under the following circumstances: (1) during any fiscal quarter (and only during such fiscal quarter), if the last reported sale price of our common stock for at least 20 trading days (whether or not consecutive) during the period of 30 consecutive trading days ending on the last trading day of the immediately preceding fiscal quarter is greater than or equal to 130% of the applicable conversion price, or $78.80 on each applicable trading day; (2) during the five consecutive business day period after any five consecutive trading day period (the “measurement period”) in which the trading price per $1,000 principal amount of notes for each trading day of such measurement period was less than 98% of the product of the last reported sale price of our common stock and the applicable conversion rate on each such trading day; or (3) upon the occurrence of specified corporate events. On or after December 15, 2023 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert their notes at any time. In addition, upon the occurrence of a make-whole fundamental change, we will, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert 2024 Notes in connection with such make-whole fundamental change. We may not redeem the 2024 Notes prior to their maturity date and no sinking fund is provided for the 2024 Notes. Upon the occurrence of a fundamental change, holders may require us to repurchase all or a portion of their 2024 Notes for cash at a price equal to 100% of the principal amount of the 2024 Notes to be repurchased, plus any accrued and unpaid interest. We considered the features embedded in the 2024 Notes other than the conversion feature, including the holders’ put feature, our call feature, and the make-whole feature, and concluded that they are not required to be bifurcated and accounted for separately from the host debt instrument. Prior to the Tax Matters Agreement settlement condition (“TMA settlement condition”), because we could only settle the 2024 Notes in cash, we determined that the conversion feature met the definition of a derivative liability. We separated the derivative liability from the host debt instrument based on the fair value of the derivative liability. As of the issuance date, March 8, 2017, the derivative liability fair value of $129.9 million was calculated using the binomial valuation approach. The residual principal amount of the 2024 Notes of $320.1 million before issuance costs was allocated to the debt component. We incurred approximately $7.7 million in transaction costs in connection with the issuance of the 2024 Notes. These costs were allocated to the debt component and recognized as a debt discount. We amortize the debt discount, including both the initial value of the derivative liability and the transaction costs, over the term of the 2024 Notes using the effective interest method. The effective interest rate of the 2024 Notes is 5.4% per year. As of September 29, 2018 , the remaining debt discount amortization period was 65 months. During the year ended July 1, 2017, we satisfied the TMA settlement condition. As such, the value of the conversion option will no longer be marked to market and was reclassified to additional paid-in capital within stockholders’ equity on our condensed consolidated balance sheet. The value of the conversion option at the time of issuance will be treated as an original issue discount for purposes of accounting for the debt component of the notes. The debt component will accrete up to the principal amount over the expected term of the debt. These accounting standards do not affect the actual amount we are required to repay, and the amount shown in the table below for the notes is the aggregate principal amount of the notes and does not reflect the debt discount we will be required to recognize. The 2024 Notes consisted of the following components as of the periods presented ( in millions ): Liability component: September 29, 2018 June 30, 2018 Principal $ 450.0 $ 450.0 Unamortized debt discount (111.5 ) (115.8 ) Net carrying amount of the liability component $ 338.5 $ 334.2 The following table sets forth interest expense information related to the 2024 Notes for the periods presented (in millions, except percentages) : Three Months Ended (in millions, except percentages) September 29, 2018 September 30, 2017 Contractual interest expense $ 0.3 $ 0.3 Amortization of the debt discount 4.3 4.1 Total interest expense $ 4.6 $ 4.4 Effective interest rate on the liability component 5.4 % 5.4 % We have the ability and intent to settle the $450 million face value of the debt in cash. Therefore, we use the treasury stock method for calculating the dilutive impact of the debt. The 2024 Notes will have no impact to diluted earnings per share until the average price of our common stock exceeds the conversion price of $60.62 .

Derivative Liability

Derivative Liability	3 Months Ended
	Sep. 29, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Liability	Note 11. Derivative Liability We estimate the fair value of the embedded derivative for the Series A Preferred Stock using the binomial lattice model. We applied the lattice model to value the embedded derivative using a “with-and-without method,” where the value of the Series A Preferred Stock, including the embedded derivative, is defined as the “with”, and the value of the Series A Preferred Stock, excluding the embedded derivative, is defined as the “without”. The lattice model requires the following inputs: (i) the Company's common stock price; (ii) conversion price; (iii) term; (iv) yield; (v) recovery rate for the Series A Preferred Stock; (vi) estimated stock volatility; and (vii) risk-free rate. The fair value of the embedded derivative was determined using Level 3 inputs under the fair value hierarchy (unobservable inputs). Changes in the inputs into this valuation model have a material impact in the estimated fair value of the embedded derivative. For example, a decrease (increase) in the stock price and the volatility results in a decrease (increase) in the estimated fair value of the embedded derivative. The changes in the fair value of the bifurcated embedded derivative for the Series A Preferred Stock are primarily related to the change in the price of our common stock and are reflected in the condensed consolidated statements of operations as “Unrealized gain (loss) on derivative liability”. Unrealized gain (loss) on derivative liability for the Series A Preferred Stock amounted to $(2.1) million and $4.2 million for the three months ended September 29, 2018 and September 30, 2017 , respectively. The following table provides a reconciliation of the fair value of the embedded derivative for the Series A Preferred Stock for the three months ended September 29, 2018 and September 30, 2017 ( in millions ): Three Months Ended September 29, 2018 September 30, 2017 Balance as of beginning of period $ 52.4 $ 51.6 Unrealized (gain) loss on the Series A Preferred Stock derivative liability 2.1 (4.2 ) Balance as of end of period $ 54.5 $ 47.4

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	3 Months Ended
	Sep. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Note 12. Goodwill and Other Intangible Assets Goodwill The following table presents the changes in goodwill by our reportable segments during the three months ended September 29, 2018 ( in millions) : Optical Communications Commercial Lasers Total Balance as of beginning of period $ 5.9 $ 5.4 $ 11.3 Foreign currency translation adjustment — — — Balance as of end of period $ 5.9 $ 5.4 $ 11.3 The following table presents the changes in goodwill by our reportable segments during the three months ended September 30, 2017 ( in millions) : Optical Communications Commercial Lasers Total Balance as of beginning of period $ 5.9 $ 5.5 $ 11.4 Foreign currency translation adjustment 0.2 (0.1 ) 0.1 Balance as of end of period $ 6.1 $ 5.4 $ 11.5 Impairment of Goodwill We review goodwill for impairment during the fourth quarter of each fiscal year or more frequently if events or circumstances indicate that an impairment loss may have occurred. In the fourth quarter of fiscal 2018 , we completed the annual impairment test of goodwill, which indicated there was no goodwill impairment. During the three months ended September 29, 2018 and September 30, 2017 , there have been no events or circumstances that have required us to perform an interim assessment of goodwill for impairment. Acquired Developed Technologies and Other Intangibles The following tables present details of our acquired developed technologies and other intangibles as of the periods presented ( in millions ): September 29, 2018: Gross Carrying Amount Accumulated Amortization Net Acquired developed technologies $ 105.6 $ (99.3 ) $ 6.3 Other intangibles 7.0 (7.0 ) — Total intangible assets $ 112.6 $ (106.3 ) $ 6.3 June 30, 2018: Gross Carrying Amount Accumulated Amortization Net Acquired developed technologies $ 105.5 $ (98.5 ) $ 7.0 Other intangibles 7.0 (7.0 ) — Total intangible assets $ 112.5 $ (105.5 ) $ 7.0 The amounts in the table above include cumulative foreign currency translation adjustments, reflecting movement in the currencies of the underlying intangibles. During the three months ended September 29, 2018 and September 30, 2017 , we recorded $0.8 million and $0.8 million , respectively, of amortization related to acquired developed technologies. The following table presents details of amortization for the periods presented (in millions ): Three Months Ended September 29, 2018 September 30, 2017 Cost of sales $ 0.8 $ 0.8 Total $ 0.8 $ 0.8 Based on the carrying amount of acquired developed technologies as of September 29, 2018 , and assuming no future impairment of the underlying assets, the estimated future amortization is as follows (in millions): Fiscal Years Remainder of 2019 $ 2.2 2020 2.9 2021 0.5 2022 0.5 Thereafter 0.2 Total amortization $ 6.3

Restructuring and Related Charg

Restructuring and Related Charges	3 Months Ended
	Sep. 29, 2018
Restructuring and Related Activities [Abstract]
Restructuring and Related Charges	Note 13. Restructuring and Related Charges We have initiated various strategic restructuring events primarily intended to reduce costs, consolidate our operations, rationalize the manufacturing of our products and align our business in response to the market conditions. The following table summarizes the activity of restructuring and related charges during the three months ended September 29, 2018 and September 30, 2017 ( in millions ): Three Months Ended September 29, 2018 September 30, 2017 Balance as of beginning of period $ 1.9 $ 3.8 Charges 1.3 2.9 Payments (1.6 ) (5.4 ) Balance as of end of period $ 1.6 $ 1.3 During the three months ended September 29, 2018 , we recorded $1.3 million in restructuring and related charges in the condensed consolidated statements of operations, primarily attributable to severance and employee related benefits. On September 5, 2018, we implemented an internal re-organization in order to extend our market leadership position by strengthening product quality, to develop new enabling technologies required to support a winning long-term portfolio roadmap, and to develop commercial proposals and new product introduction (“NPI”) priorities to maintain and grow our position while driving new customer and eco-system partner engagements. During the three months ended September 30, 2017, we recorded $2.9 million in restructuring and related charges in the condensed consolidated statements of operations, of which $(0.1) million was severance costs and $3.0 million related to cost to vacate facilities, lease termination costs, and temporary labor, payroll tax, and other related costs connected with employee benefits, materials used in set up and production activities.

Income Taxes

Income Taxes	3 Months Ended
	Sep. 29, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Note 14. Income Taxes The comparability of our operating results in the first quarter of fiscal 2019 compared to the corresponding prior year period was impacted by the U.S. Tax Cuts and Jobs Act of 2017 (the Tax Act), which was enacted on December 22, 2017. The Tax Act introduced significant changes to U.S. income tax law including reducing the U.S. federal statutory tax rate from 35% to 21% and imposing new taxes on certain foreign-sourced earnings and certain intercompany payments. Due to the timing of the enactment and the complexity involved in applying the provisions of the Tax Act, we made reasonable estimates of the effects and recorded provisional amounts in our financial statements as of fiscal 2018 in accordance with SEC Staff Accounting Bulletin No. 118 (SAB 118). No further adjustments were made to the provisional amounts in the first quarter of fiscal 2019. The accounting for the tax effects of the Tax Act will be completed within the measurement period in accordance with SAB 118. Our tax provision for interim periods is determined using an estimate of our annual effective tax rate, adjusted for discrete items, if any, that arise during the period. Each quarter, we update our estimate of the annual effective tax rate, and if the estimated annual effective tax rate changes, we make a cumulative adjustment in such period. Our quarterly tax provision, and estimate of our annual effective tax rate, is subject to variation due to several factors, including variability in pre-tax income (or loss), the mix of jurisdictions to which such income relates, changes in how we do business, and tax law developments. Our estimated effective tax rate for the year differs from the 21% U.S. statutory rate primarily due to the benefit of foreign earnings of our subsidiaries being taxed at rates lower than the U.S. statutory rate. We recorded a tax expense of $5.2 million for the three months ended September 29, 2018. Our provision for income taxes for the three months September 29, 2018 varied from the 21% U.S. statutory rate primarily due to earnings in our foreign subsidiaries, the U.S. research and development tax credit, and the tax effects of stock-based compensation, partially offset by the tax effect of Global Intangible Low-Taxed Income (GILTI) and subpart F income inclusion. We recorded a tax benefit of $(3.6) million for the three months ended September 30, 2017. Our provision for income taxes for the three months ended September 30, 2017 varied from the previous U.S. federal statutory income tax rate of 35% primarily due to earnings in foreign operations, the tax benefit from excess stock-based compensation deductions, and the non-taxable unrealized gain from the embedded derivatives for the Series A Preferred Stock. As of September 29, 2018 , we had $9.0 million of unrecognized tax benefits, which, if recognized, would affect the effective tax rate. We are subject to examination of income tax returns by various domestic and foreign tax authorities. The timing of resolutions and closures of tax audits is highly unpredictable. Given the uncertainty, it is reasonably possible that certain tax audits may be concluded within the next 12 months. An estimate of the range of increase or decrease that could occur in the next twelve months cannot be made. However, the estimated impact to tax expense and net income from the resolution and closure of tax exams is not expected to be significant within the next 12 months. On July 24, 2018, the Ninth Circuit Court of Appeals (the “Court”) issued an opinion in Altera Corp. v. Commissioner requiring related parties in an intercompany cost sharing arrangement to share expenses related to share-based compensation. This opinion reversed the prior decision of the United States Tax Court. On August 7, 2018, the Court withdrew the opinion issued on July 24, 2018 to allow time for a reconstituted panel of judges to confer. We will continue to monitor the case and potential impact to our consolidated financial statements.

Stock-Based Compensation and St

Stock-Based Compensation and Stock Plans	3 Months Ended
	Sep. 29, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation and Stock Plans	Note 15. Stock-Based Compensation and Stock Plans Description of Lumentum Stock-Based Benefit Plans Equity Incentive Plan On June 23, 2015, we adopted, and the board of directors of JDSU approved, the 2015 Equity Incentive Plan (the “2015 Plan”) under which 8.5 million shares of our common stock were authorized for issuance, which was ratified by our board of directors in August 2015. In connection with our Separation from JDSU on July 31, 2015, outstanding JDSU equity-based awards held by service providers continuing in service after the Separation were converted into equity-based awards under the 2015 Plan reducing the number of shares remaining available for grant under the 2015 Plan. Immediately following our Separation from JDSU, 2.1 million shares of our common stock were reserved pursuant to outstanding equity-based awards under the 2015 Plan that were converted from JDSU equity-based awards. On November 4, 2016, our stockholders approved an amendment to increase the number of shares that may be issued under the 2015 Plan by 3.0 million shares, and certain other material terms of the 2015 Plan. As of September 29, 2018 , we had 2.0 million shares subject to restricted stock units, restricted stock awards, and performance stock units issued and outstanding under the 2015 Plan. Restricted stock units, restricted stock awards, and performance stock units are performance-based, time-based or a combination of both and are expected to vest over one to four years. The fair value of these grants is based on the closing market price of our common stock on the date of award. The exercise price for stock options is equal to the fair value of the underlying stock at the date of grant. We issue new shares of common stock upon exercise of stock options. Options generally become exercisable over a three -year or four -year period and, if not exercised, expire from five to ten years after the date of grant. As of September 29, 2018 , 5.0 million shares of common stock under the 2015 Plan were available for grant. Restricted Stock Units Restricted stock units (“RSUs”) under the 2015 Plan are grants of shares of our common stock, the vesting of which is based on the requisite service requirement. Generally, our RSUs are subject to forfeiture and expected to vest over one to four years. For annual refresh grants, RSUs generally vest ratably on an annual, or combination of annual and quarterly, basis over three years . Restricted Stock Awards Restricted stock awards (“RSAs”) under the 2015 Plan are grants of shares of our common stock that are subject to various restrictions, including restrictions on transferability and forfeiture provisions. RSAs are expected to vest over one to four years, and the shares acquired may not be transferred by the holder until the vesting conditions (if any) are satisfied. Performance Stock Units Performance stock units (“PSUs”) under the 2015 Plan are grants of shares of our common stock that vest upon the achievement of certain performance and service conditions. We begin recognizing compensation expense when we conclude that it is probable that the performance conditions will be achieved. We reassess the probability of vesting at each reporting period and adjust our compensation cost based on this probability assessment. Our PSUs are subject to risk of forfeiture until performance and service conditions are satisfied and generally vest over three years. During the three months ended September 29, 2018 , our board of directors preliminary approved the grant of 0.2 million PSUs to senior members of our management team. The grant date has not been established for these awards as the performance targets will only be set and approved by our board in the quarter ending December 29, 2018. As such, no stock-based compensation has been recorded for these grants during the three months ended September 29, 2018 . Employee Stock Purchase Plan On June 23, 2015, we adopted, and the board of directors of JDSU approved, the 2015 Employee Stock Purchase Plan (the “2015 Purchase Plan”) under which 3.0 million shares of our common stock were authorized for issuance, which was ratified by our board of directors in August 2015. The 2015 Purchase Plan provides eligible employees with the opportunity to acquire an ownership interest in the Company through periodic payroll deductions and provides a 15% purchase price discount as well as a six -month look-back period. The 2015 Purchase Plan is structured as a qualified employee stock purchase plan under Section 423 of the Internal Revenue Code of 1986. However, the 2015 Purchase Plan is not intended to be a qualified pension, profit sharing or stock bonus plan under Section 401(a) of the Internal Revenue Code of 1986 and is not subject to the provisions of the Employee Retirement Income Security Act of 1974. The 2015 Purchase Plan will terminate upon the date on which all shares available for issuance have been sold. Of the 3.0 million shares authorized under the 2015 Purchase Plan, 2.3 million shares remained available for issuance as of September 29, 2018 . Stock-Based Compensation The impact on our results of operations of recording stock-based compensation by function for the three months ended September 29, 2018 and September 30, 2017 was as follows (in millions) : Three Months Ended September 29, 2018 September 30, 2017 Cost of sales $ 3.3 $ 2.7 Research and development 2.8 3.1 Selling, general and administrative 4.7 3.5 $ 10.8 $ 9.3 Approximately $2.1 million and $2.6 million of stock-based compensation was capitalized to inventory as of September 29, 2018 and June 30, 2018 , respectively. Stock Option and Stock Award Activity We did not grant any stock options during the three months ended September 29, 2018 and September 30, 2017 . As of September 29, 2018 and June 30, 2018, there were no options outstanding under the 2015 Plan. During the three months ended September 30, 2017 , there were 40,270 options exercised by our employees with the total intrinsic value of $0.7 million . The following table summarizes our awards activity for the three months ended September 29, 2018 (in millions, except per share amounts) : Restricted Stock Units Restricted Stock Awards Performance Stock Units Number of Shares Weighted-Average Grant Date Fair Value per Share Number of Shares Weighted-Average Grant Date Fair Value per Share Number of Shares (1) Weighted-Average Grant Date Fair Value per Share Unvested balance as of beginning of period 1.7 $ 43.1 0.1 $ 32.5 0.2 $ 52.0 Granted 0.7 67.8 — — — — Vested (0.5 ) 38.4 — — (0.1 ) 52.0 Canceled (0.1 ) 49.6 — — — — Unvested balance as of end of period 1.8 $ 55.2 0.1 $ 32.5 0.1 $ — (1) In fiscal 2018, we granted 0.1 million PSUs to senior members of our management team subject to revenue performance condition. The number of awards granted in fiscal 2018 represented 100% of target goal; under the terms of the awards, the recipient could earn between 0% and 200% of the original grant. The performance condition was achieved in fiscal 2018. During the three months ended September 29, 2018, our board of directors approved an increase in the original number of PSUs based on the actual achievement. As of September 29, 2018 , $97.8 million of stock-based compensation cost related to awards granted to our employees remains to be amortized. That cost is expected to be recognized over an estimated amortization period of 2.1 years . A summary of awards available for grant is as follows (in millions) : Awards Available for Grant Balance as of beginning of period 5.6 Granted (0.7 ) Canceled 0.1 Balance as of end of period 5.0 Employee Stock Purchase Plan Activity The 2015 Purchase Plan expense for the three months ended September 29, 2018 and September 30, 2017 was $1.0 million and $0.8 million , respectively. The expense related to the 2015 Purchase Plan is recorded on a straight-line basis over the relevant subscription period. During the three months ended September 29, 2018 and September 30, 2017 , there were no shares issued to employees through the 2015 Purchase Plan. We estimate the fair value of the 2015 Purchase Plan shares on the date of grant using the Black-Scholes option-pricing model. During the three months ended September 29, 2018 and September 30, 2017 , the assumptions used to estimate the fair value of the 2015 Purchase Plan shares to be issued were as follows: September 29, 2018 September 30, 2017 Expected term (years) 0.5 0.5 Expected volatility 58.8 % 53.0 % Risk-free interest rate 2.02 % 1.02 % Dividend yield — % — %

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Sep. 29, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 16. Commitments and Contingencies Operating Leases We lease certain real and personal property from unrelated third parties under non-cancellable operating leases that expire at various dates through fiscal 2026. Certain leases require us to pay property taxes, insurance and routine maintenance, and include escalation clauses. As of September 29, 2018 , the future minimum annual lease payments under non-cancellable operating leases were as follows ( in millions ): Fiscal Years Remainder of 2019 $ 8.8 2020 6.5 2021 5.1 2022 3.4 2023 2.4 Thereafter 1.8 Total minimum operating lease payments $ 28.0 During the three months ended September 29, 2018 and September 30, 2017 , rental expense relating to building and equipment was $2.8 million and $3.4 million , respectively. Capital Lease As of September 29, 2018 , equipment acquired under a capital lease agreement was $15.6 million . Our capital lease asset is included in property, plant and equipment, net in our condensed consolidated balance sheets as of September 29, 2018 . Amortization expense on this capital lease asset is recorded as depreciation expense and is included in cost of sales in our condensed consolidated statements of operations for the three months ended September 29, 2018 . Our capital lease obligation is recorded at the lesser of the estimated fair market value of the leased property or the net present value of the aggregate future minimum lease payments and is included in other current liabilities and other non-current liabilities in our condensed consolidated balance sheets as of September 29, 2018 . Refer to “ Note 6. Balance Sheet Details ” for capital lease obligation amounts in other current liabilities and other non-current liabilities. Interest on these obligations is included in interest expense in our condensed consolidated statements of operations. As of September 29, 2018 the future minimum annual lease payments under our capital lease were as follows ( in millions ): Fiscal Years Remainder of 2019 $ 6.7 2020 0.4 Total minimum capital lease payments $ 7.1 Less: amount representing interest $ (0.1 ) Present value of capital lease obligation $ 7.0 Acquisition Contingencies At the time of acquisition in February 2017, we incurred liabilities in the amount of $3.6 million . The amount of up to $3.0 million is expected to be paid within the following 12 months contingent upon meeting certain production targets, and is included in other current liabilities on our consolidated balance sheet as of September 29, 2018 . We retained $1.0 million of the purchase price as security for any potential liabilities of the seller under the representations, warranties and indemnifications included in the purchase agreement. The amount of $1.0 million was fully paid to the seller during the three months ended September 29, 2018 . 0.25% Convertible Senior Notes due 2024 The future interest and principal payments related to the 2024 Notes are as follows as of September 29, 2018 : Fiscal Years Remainder of 2019 $ 0.6 2020 1.1 2021 1.1 2022 1.1 2023 1.1 Thereafter 451.2 Total 2024 Notes payments $ 456.2 Purchase Obligations Purchase obligations of $206.5 million as of September 29, 2018 , represent legally-binding commitments to purchase inventory and other commitments made in the normal course of business to meet operational requirements. Although open purchase orders are considered enforceable and legally binding, the terms generally allow the option to cancel, reschedule and adjust the requirements based on our business needs prior to the delivery of goods or performance of services. Obligations to purchase inventory and other commitments are generally expected to be fulfilled within one year. We depend on a limited number of contract manufacturers, subcontractors and suppliers for raw materials, packages and standard components. We generally purchase these single or limited source products through standard purchase orders or one -year supply agreements and have no significant long-term guaranteed supply agreements with such vendors. While we seek to maintain a sufficient safety stock of such products and maintain on-going communications with our suppliers to guard against interruptions or cessation of supply, our business and results of operations could be adversely affected by a stoppage or delay of supply, substitution of more expensive or less reliable products, receipt of defective parts or contaminated materials, increases in the price of such supplies, or our inability to obtain reduced pricing from our suppliers in response to competitive pressures. Product Warranties We provide reserves for the estimated costs of product warranties at the time revenue is recognized. We typically offer a twelve month warranty for most of our products. However, in some instances depending upon the product, product component or application of our products by the end customer, our warranties can vary and generally range from six months to five years. We estimate the costs of our warranty obligations on an annualized basis based on our historical experience of known product failure rates, use of materials to repair or replace defective products and service delivery costs incurred in correcting product failures. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise with specific products. We assess the adequacy of our recorded warranty liabilities and adjust the amounts as necessary. The following table presents the changes in our warranty reserve during the three months ended September 29, 2018 and September 30, 2017 ( in millions ): Three Months Ended September 29, 2018 September 30, 2017 Balance as of beginning of period $ 6.6 $ 9.7 Provision for warranty 1.2 1.0 Utilization of reserve (1.2 ) (1.3 ) Balance as of end of period $ 6.6 $ 9.4 Environmental Liabilities Our research and development (“R&D”), manufacturing and distribution operations involve the use of hazardous substances and are regulated under international, federal, state and local laws governing health and safety and the environment. We apply strict standards for protection of the environment and occupational health and safety to sites inside and outside the United States, even if not subject to regulations imposed by foreign governments. We believe that our properties and operations at our facilities comply in all material respects with applicable environmental laws and occupational health and safety laws. However, the risk of environmental liabilities cannot be completely eliminated and there can be no assurance that the application of environmental and health and safety laws will not require us to incur significant expenditures. We are also regulated under a number of international, federal, state and local laws regarding recycling, product packaging and product content requirements. The environmental, product content/disposal and recycling laws are gradually becoming more stringent and may cause us to incur significant expenditures in the future. In connection with the Separation, we agreed to indemnify Viavi for any liability associated with contamination from past operations at all properties transferred to us from Viavi, to the extent the resulting issues primarily related to our business. Legal Proceedings We are subject to a variety of claims and suits that arise from time to time in the ordinary course of our business. While management currently believes that resolving claims against us, individually or in the aggregate, will not have a material adverse impact on our financial position, results of operations or statements of cash flows, these matters are subject to inherent uncertainties and management’s view of these matters may change in the future. We accrue for loss contingencies when it is both probable that we will incur the loss and when we can reasonably estimate the amount of the loss or range of loss. Indemnifications In the normal course of business, we enter into agreements that contain a variety of representations and warranties and provide for general indemnification. Exposure under these agreements is unknown because claims may be made against us in the future and we may record charges in the future as a result of these indemnification obligations. As of September 29, 2018 , we did not have any material indemnification claims that were probable or reasonably possible. Audit Proceedings We are under audit by various domestic and foreign tax authorities with regards to income tax and indirect tax matters. In some, although not all cases, we have reserved for potential adjustments to our provision for income taxes and accrual of indirect taxes that may result from examinations by these tax authorities or final outcomes in judicial proceedings, and we believe that the final outcome of these examinations, agreements or judicial proceedings will not have a material effect on our results of operations. If events occur which indicate payment of these amounts is unnecessary, the reversal of the liabilities would result in the recognition of benefits in the period we determine the liabilities are no longer necessary. If our estimates of the federal, state, and foreign income tax liabilities and indirect tax liabilities are less than the ultimate assessment, it could result in a further charge to expense.

Operating Segments and Geograph

Operating Segments and Geographic Information	3 Months Ended
	Sep. 29, 2018
Segment Reporting [Abstract]
Operating Segments and Geographic Information	Note 17. Operating Segments and Geographic Information Our chief executive officer is our Chief Operating Decision Maker (“CODM”). The CODM allocates resources to the segments based on their business prospects, competitive factors, net revenue and gross margin. We do not track all of our property, plant and equipment by operating segments. The geographic identification of these assets is set forth below. We are an industry leading provider of optical and photonic products defined by revenue and market share addressing a range of end-market applications including optical communications and commercial lasers. We have two operating segments, Optical Communications, which we refer to as OpComms, and Commercial Lasers, which we refer to as Lasers. Our OpComms products address the following markets: telecommunications (“Telecom”), data communications (“Datacom”), and consumer and industrial (“Consumer and Industrial”). The two operating segments were primarily determined based on how the CODM views and evaluates our operations. Operating results are regularly reviewed by the CODM to make decisions about resources to be allocated to the segments and to assess their performance. Other factors, including market separation and customer specific applications, go-to-market channels, products and manufacturing, are considered in determining the formation of these operating segments. We do not allocate research and development, sales and marketing, or general and administrative expenses to our segments because management does not include the information in its measurement of the performance of the operating segments. In addition, we do not allocate amortization and impairment of acquisition-related intangible assets, stock-based compensation and certain other charges impacting the gross margin of each segment because management does not include this information in its measurement of the performance of the operating segments. Information on reportable segments utilized by our CODM is as follows ( in millions) : Three Months Ended September 29, 2018 September 30, 2017 Net revenue: OpComms $ 310.1 $ 207.9 Lasers 44.0 35.3 Net revenue $ 354.1 $ 243.2 Gross profit: OpComms 124.9 72.1 Lasers 17.7 10.6 Total segment gross profit 142.6 82.7 Unallocated corporate items: Stock-based compensation (3.3 ) (2.7 ) Amortization of intangibles (0.8 ) (0.8 ) Other charges (1) (12.5 ) (10.7 ) Gross profit $ 126.0 $ 68.5 (1) “Other charges” of unallocated corporate items for the three months ended September 29, 2018 primarily include set-up costs of our facility in Thailand, including costs of transferring product lines to Thailand of $12.7 million . During the three months ended September 30, 2017 , “other charges” of unallocated corporate items primarily consisted of set-up costs of our facility in Thailand of $3.1 million , as well as inventory write-downs due to canceled programs not allocated to the segments of $7.0 million . The table below discloses our total net revenue attributable to each of our two reportable segments. In addition, it discloses the percentage of our total net revenue attributable to our product offerings which serve the Telecom, Datacom, and Consumer and Industrial markets which accounted for 10% or more of our total net revenue during the periods presented: Three Months Ended September 29, 2018 September 30, 2017 OpComms: $ 310.1 $ 207.9 Telecom 142.9 110.4 Datacom 34.2 45.2 Consumer and Industrial 133.0 52.3 Lasers $ 44.0 $ 35.3 We operate in three geographic regions: Americas, Asia-Pacific, and EMEA (Europe, Middle East, and Africa). Net revenue is assigned to the geographic region and country where our product is initially shipped. For example, certain customers may request shipment of our product to a contract manufacturer in one country, which may differ from the location of their end customers. The following table presents net revenue by the three geographic regions we operate in and net revenue from countries that represented 10% or more of our total net revenue (in millions, except percentage data): Three Months Ended September 29, 2018 September 30, 2017 Net revenue: Americas: United States $ 21.9 6.2 % $ 33.6 13.8 % Mexico 56.3 15.9 24.8 10.3 Other Americas 0.9 0.3 2.2 0.9 Total Americas $ 79.1 22.4 % $ 60.6 25.0 % Asia-Pacific: Hong Kong $ 65.5 18.5 % $ 48.9 20.1 % Japan 36.1 10.2 34.1 14.0 South Korea 70.0 19.8 10.9 4.5 Other Asia-Pacific 74.1 20.9 63.3 26.0 Total Asia-Pacific $ 245.7 69.4 % $ 157.2 64.6 % EMEA $ 29.3 8.2 % $ 25.4 10.4 % Total net revenue $ 354.1 $ 243.2 Our net revenue from Mexico increased due to increased demand for our ROADM products from one of our large customers who manufactures in Mexico, while net revenue from Hong Kong and South Korea grew due to our 3D sensing ramp for mobile devices. During the three months ended September 29, 2018 and September 30, 2017 , net revenue generated from a single customer which represented 10% or greater of total net revenue is summarized as follows: Three Months Ended September 29, 2018 September 30, 2017 Customer A 30.5 % 16.3 % Customer B 15.0 % * Customer C 13.0 % 14.2 % Customer D * 10.4 % *Represents less than 10% of total net revenue Long-lived assets, namely net property, plant and equipment were identified based on the physical location of the assets in the corresponding geographic areas (in millions) : As of September 29, 2018 June 30, 2018 Property, Plant and Equipment, net United States $ 103.6 $ 97.6 China 62.1 70.0 Thailand 131.3 107.4 Other countries 21.6 31.9 Total long-lived assets $ 318.6 $ 306.9 We purchase a substantial portion of our inventory from contract manufacturers and vendors located primarily in Taiwan, Thailand, and China. During the three months ended September 29, 2018 and September 30, 2017 , net inventory purchased from a single contract manufacturer which represented 10% or greater of total net purchases is summarized as follows: Three Months Ended September 29, 2018 September 30, 2017 Vendor A 51.5 % 44.9 % Vendor B 25.1 % 25.7 % Vendor C * 10.9 % *Represents less than 10% of total net purchases

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Sep. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation The preparation of the condensed consolidated financial statements in accordance with U.S. generally accepted accounting principles (“GAAP”) 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 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.
Fiscal Years	Fiscal Years We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th.
Principles of Consolidation	Principles of Consolidation These interim unaudited condensed consolidated financial statements include the accounts of the Company and its wholly-owned subsidiaries. All inter-company transactions and balances have been eliminated in consolidation.
Reclassifications	Certain prior period amounts have been reclassified to conform to the current year presentation on the notes to condensed consolidated financial statements. The reclassification of the prior period amounts did not impact previously reported condensed consolidated financial statements.
Revenue from Contract with Customer	Shipping and Handling Costs We record shipping and handling costs related to revenue transactions within cost of sales as a period cost. Contract Costs The Company recognizes the incremental direct costs of obtaining a contract, which consist of sales commissions, when control over the products they relate to transfers to the customer. Applying the practical expedient, the Company recognizes commissions as expense when incurred, as the amortization period of the commission asset the Company would have otherwise recognized is less than one year. Contract Balances The Company records accounts receivable when it has an unconditional right to consideration. Contract liabilities are recorded when cash payments are received or due in advance of performance. Contract liabilities consist of advance payments and deferred revenue, where the Company has unsatisfied performance obligations. Contract liabilities are classified as deferred revenue and customer deposits and included in other current liabilities of our condensed consolidated balance sheet. Payment terms vary by customer. The time between invoicing and when payment is due is not significant. Revenue Recognition Policy Pursuant to Topic 606, our revenues are recognized upon the application of the following steps: • identification of the contract, or contracts, with a customer; • identification of the performance obligations in the contract; • determination of the transaction price; • allocation of the transaction price to the performance obligations in the contract; and • recognition of revenues when, or as, the contractual performance obligations are satisfied The majority of our revenue comes from product sales, consisting of sales of Lasers and OpComms hardware products to our customers. Our revenue contracts generally include only one performance obligation. Revenues are recognized at a point in time when control of the promised goods or services is transferred to our customers upon shipment or delivery, in an amount that reflects the consideration we expect to be entitled to in exchange for those goods or services. We have entered into vendor managed inventory (“VMI”) programs with our customers. Under these arrangements, we receive purchase orders from our customers, and the inventory is shipped to the VMI location upon receipt of the purchase order. The customer then pulls the inventory from the VMI hub based on its production needs. Revenue under VMI programs is recognized when control transfers to the customer, which is generally upon pull of inventory by the customer from the hub. Revenue from all sales types is recognized at transaction price. The transaction price is determined based on the consideration to which we will be entitled in exchange for transferring goods or services to the customer adjusted for estimated variable consideration, if any. We typically estimate the transaction price impact of discounts offered to the customers for early payments on receivables or net of accruals for estimated sales returns. These estimates are based on historical returns, analysis of credit memo data and other known factors. Actual returns could differ from these estimates. We allocate the transaction price to each distinct product based on its relative standalone selling price. The product price as specified on the purchase order is considered the standalone selling price as it is an observable input that depicts the price as if sold to a similar customer in similar circumstances. Taxes assessed by a governmental authority that are both imposed on and concurrent with a specific revenue-producing transaction, that are collected by us from a customer and deposited with the relevant government authority, are excluded from revenue. Our revenue arrangements do not contain significant financing components as our standard payment terms are less than one year. If a customer pays consideration, or Lumentum has a right to an amount of consideration that is unconditional before we transfer a good or service to the customer, those amounts are classified as deferred income/advances received from customers which are included in other current liabilities or other long-term liabilities when the payment is made or it is due, whichever is earlier. Transaction Price Allocated to the Remaining Performance Obligations Remaining performance obligations represent the transaction price allocated to performances obligations that are unsatisfied or partially unsatisfied as of the end of the reporting period. Unsatisfied and partially unsatisfied performance obligations consist of contract liabilities and non-cancellable backlog. Non-cancellable backlog includes goods and services for which customer purchase orders have been accepted that are scheduled or in the process of being scheduled for shipment. Disaggregation of Revenue We disaggregate revenue by geography and by product, no other level of disaggregation is required considering the type of products, customer, markets, contracts, duration of contracts, timing of transfer of control and sales channels, based on the information that our chief operating decision maker uses to manage the business.
Warranty	Warranty Hardware products regularly include warranties to the end customers such that the product continues to function according to published specifications. We typically offer a twelve month warranty for most of our products. However, in some instances depending upon the product, specific market, product line and geography we deal in, and what is common in the industry, our warranties can vary and range from six months to five years . These standard warranties are assurance type warranties and do not offer any services in addition to the assurance that the product will continue working as specified. Therefore, warranties are not considered separate performance obligations in the arrangement. Instead, the expected cost of warranty is accrued as expense in accordance with authoritative guidance. We provide reserves for the estimated costs of product warranties at the time revenue is recognized. We estimate the costs of our warranty obligations based on our historical experience of known product failure rates, use of materials to repair or replace defective products and service delivery costs incurred in correcting product failures. In addition, from time to time, specific warranty accruals may be made if unforeseen technical problems arise.
Accounting Pronouncements Recently Adopted and Accounting Pronouncements Not Yet Effective	Accounting Pronouncements Recently Adopted In May 2014, the Financial Accounting Standards Board (“FASB”) issued ASU 2014-09 (Topic 606), which amended the existing accounting standards for revenue recognition. Topic 606 outlines a single comprehensive model for entities to use in accounting for revenue arising from contracts with customers. The guidance is effective for annual reporting periods including interim reporting periods beginning after December 15, 2017. On July 1, 2018, we adopted Topic 606 using the modified retrospective method applied to all contracts that are not completed contracts at the date of initial adoption (i.e., July 1, 2018). Results for reporting periods after July 1, 2018 are presented under Topic 606, while prior period amounts are not adjusted and continue to be reported in accordance with our historic accounting under Topic 605. The adoption of Topic 606 did not have a material impact on the nature and timing of our revenues, condensed consolidated statements of operations, cash flows, and balance sheet and therefore, we do not present results for the three months ended September 29, 2018 under Topic 605. Refer to “ Note 1. Description of Business and Summary of Significant Accounting Policies ” for the changes in our accounting policies due to adoption of Topic 606. Select condensed consolidated balance sheet line items, as if we had adopted Topic 606 in previous years, are summarized below as of the periods presented: June 30, 2018 Adjustments July 1, 2018 Assets: Accounts receivable, net $ 197.1 $ 0.6 $ 197.7 Inventories 153.6 (1.2 ) 152.4 Stockholders’ equity: Retained earnings $ 166.4 $ (0.6 ) $ 165.8 In August 2016, FASB issued ASU 2016-15, S tatement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments , which clarifies how companies present and classify certain cash receipts and cash payments in the statement of cash flows. The amendments contained in ASU 2016-15 are effective for interim and annual periods beginning after December 15, 2017. We adopted ASU 2016-15 on July 1, 2018 on a prospective basis. The application of ASU 2016-15 will have a material impact on our consolidated financial statements if we elect to settle the principal amounts of our 2024 Notes (refer to “ Note 10. Convertible Senior Notes ”) in cash. The principal repayment will be bifurcated between (i) cash outflows for operating activities of $137.6 million for the portion related to accreted interest attributable to debt discount, and (ii) financing activities for the remainder of $312.4 million . In January 2017, FASB issued ASU 2017-01, Business Combinations (Topic 805) , which clarifies the definition of a business. For accounting and financial reporting purposes, businesses are generally comprised of three elements; inputs, processes, and outputs. Integrated sets of assets and activities capable of providing these three elements may not always be considered a business, and the lack of one of the three elements does not always disqualify the set from being a business. The issuance of ASU 2017-01 provides a clarifying screen to determine when a set of assets and activities is not a business. Primarily, the screen requires that when substantially all of the fair value of the gross assets acquired is concentrated in a single identifiable asset or group of similar identifiable assets, the set is not a business. The amendments contained in ASU 2017-01 are effective for annual periods beginning after December 15, 2017, including interim periods within those periods. We adopted ASU 2017-01 on July 1, 2018 on a prospective basis. The implementation of ASU 2017-01 did not have an impact on our financial statements. In October 2016, FASB issued ASU 2016-16, Accounting for Income Taxes: Intra-Entity Asset Transfers of Assets other than Inventory. The new guidance removes the prohibition in ASC 740 against the immediate recognition of the current and deferred income tax effects of intra-entity transfers of assets other than inventory. The new guidance became effective for us in the first quarter of our fiscal 2019. The adoption of ASU 2016-16 did not have a material impact on our financial statements. Accounting Pronouncements Not Yet Effective In August 2018, the Securities and Exchange Commission (“SEC”) adopted amendments to certain disclosure requirements in Securities Act Release No. 33-10532, Disclosure Update and Simplification . The amendments will become effective on November 5, 2018. The SEC staff subsequently indicated that it would not object if a filer’s first presentation of changes in shareholders’ equity is included in its Form 10-Q for the quarter that begins after the final rule’s effective date. Among the amendments is the requirement to present the changes in shareholders’ equity in the interim financial statements (either in a separate statement or footnote) in quarterly reports on Form 10-Q. The analysis should present a reconciliation of the beginning balance to the ending balance of each period for which a consolidated statement of operations is required to be filed. We will include the first presentation of changes in stockholders’ equity on Form 10-Q in our third quarter of fiscal 2019. In August 2018, FASB issued ASU 2018-15, Intangibles-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. ASU 2018-15 requires an entity in a hosting arrangement that is a service contract to follow the guidance in Subtopic 350-40 to determine which implementation costs to capitalize as an asset related to the service contract and which costs to expense. Implementation costs capitalized must be expensed over the term of the hosting arrangement, including the period covered by an option to extend the arrangement. The standard is effective for fiscal years beginning after December 15, 2019, and interim periods within those fiscal years, and should be applied either retrospectively or prospectively to all implementation costs incurred after the date of adoption. Early adoption is permitted, including adoption in any interim period, for all entities. ASU 2018-15 is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of ASU 2018-15 on our consolidated financial statements. In August 2018, FASB issued ASU 2018-14, Compensation-Retirement Benefits-Defined Benefit Plans-General (Topic 715-20): Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans . ASU 2018-14 modifies the disclosure requirements for defined benefit pension plans and other postretirement benefit plans. The new guidance is effective for fiscal years ending after December 15, 2020 and early adoption is permitted. ASU 2018-14 should be applied retrospectively to all periods presented and is effective for us in our first quarter of fiscal 2022. We are currently evaluating the impact of ASU 2018-14 on our consolidated financial statements. In August 2018, FASB issued ASU 2018-13, Fair Value Measurement (Topic 820): Disclosure Framework-Changes to the Disclosure Requirements for Fair Value Measurement. ASU 2018-13 modifies the disclosure requirements for fair value measurements. The new guidance is effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2019. Entities are permitted to early adopt any removed or modified disclosures upon issuance of ASU 2018-13 and delay adoption of the additional disclosures until the effective date. The standard is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of ASU 2018-13 on our consolidated financial statements and related disclosures. In February 2018, FASB issued ASU 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income , which allows companies to reclassify stranded tax effects resulting from the Tax Act, from accumulated other comprehensive income to retained earnings. The guidance also requires certain new disclosures regardless of the election. The amendments in ASU 2018-02 are effective for all entities for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. ASU 2018-02 is effective for us in the first quarter of fiscal 2020. We are currently evaluating the impact of our pending adoption of ASU 2018-02 on our consolidated financial statements. In January 2017, FASB issued ASU 2017-04, Intangibles - Goodwill and Other (Topic 350): Simplifying the Accounting for Goodwill Impairment . ASU 2017-04 removes the requirement to perform a hypothetical purchase price allocation to measure goodwill impairment. A goodwill impairment charge will be the amount by which a reporting unit's carrying value exceeds its fair value, not to exceed the carrying amount of goodwill. The amendments contained in ASU 2017-04 are effective for interim and annual periods beginning after December 15, 2019, with early adoption permitted, which should be applied prospectively. We plan to adopt the accounting standard update in our first quarter of fiscal 2020. We are currently evaluating the impact of ASU 2017-04 on our consolidated financial statements. In February 2016, FASB issued ASU 2016-02, Leases . The new guidance generally requires an entity to recognize on its balance sheet operating and financing lease liabilities and corresponding right-of-use assets. The new guidance contained in ASU 2016-02 is effective for annual periods beginning after December 15, 2018, including interim periods within those periods, with early adoption permitted. The standard is effective for us in our first quarter of fiscal 2020 where we will be required to recognize and measure leases existing at, or entered into after, the beginning of the earliest comparative period presented using a modified retrospective approach, with an option to elect certain practical expedients. Based on our current lease portfolio, we estimate the value of leased assets and liabilities that may be recognized will be material. We are continuing to evaluate the impact of ASU 2016-02 which is subject to change.
Fair Value Measurements	We determine fair value based on the fair value hierarchy, which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. The fair value assumes that the transaction to sell the asset or transfer the liability occurs in the principal or most advantageous market for the asset or liability and establishes that the fair value of an asset or liability shall be determined based on the assumptions that market participants would use in pricing the asset or liability. The classification of a financial asset or liability within the hierarchy is based upon the lowest level input that is significant to the fair value measurement. The fair value hierarchy prioritizes the inputs into three levels that may be used to measure fair value: Level 1: Inputs are unadjusted quoted prices in active markets for identical assets or liabilities. Level 2: Inputs are quoted prices for similar assets and liabilities in active markets or inputs that are observable for the asset or liability, either directly or indirectly through market corroboration, for substantially the full term of the financial instrument. Level 3: Inputs are unobservable inputs based on our assumptions. The fair value of the Company’s Level 1 financial instruments, such as money market funds, which are traded in active markets, is based on quoted market prices for identical instruments. The fair value of the Company’s Level 2 fixed income securities is obtained from an independent pricing service, which may use quoted market prices for identical or comparable instruments or model driven valuations using observable market data or inputs corroborated by observable market data. Our marketable securities are held by custodians who obtain investment prices from a third-party pricing provider that incorporates standard inputs in various asset price models. The Company’s procedures include controls to ensure that appropriate fair values are recorded, including comparing the fair values obtained from the Company’s pricing service against fair values obtained from another independent source. We estimate the fair value of the embedded derivative for the Series A Preferred Stock using the binomial lattice model. The lattice model requires the various assumptions to be made to determine the fair value of the embedded derivatives. These assumptions represent Level 3 inputs. Refer to “ Note 11. Derivative Liability ” in the Notes to Unaudited Condensed Consolidated Financial Statements. In February 2017, we completed the acquisition of a privately held company to enhance our manufacturing and vertical integration capabilities for a total purchase consideration of $8.7 million . We estimated the fair value of our Level 3 contingent consideration related to this acquisition at the present value of the expected contingent payments, determined using a probabilistic approach. We are required to reassess the fair value of contingent payments on a periodic basis. We estimated the likelihood of meeting the production targets at 90 percent and recorded the fair value of such contingent consideration in other current liabilities on the condensed consolidated balance sheet as of September 29, 2018 . This contingent consideration will result in a cash payment of $3.0 million , if and when the production targets are achieved, which we expect to occur within the following 12 months . There was no change in the fair value of our contingent consideration during the three months ended September 29, 2018 and September 30, 2017 . Our pension assets consist of multiple institutional funds (“pension funds”) of which the fair values are based on the quoted prices of the underlying funds. Pension funds are classified as Level 2 assets since such funds are not directly traded in active markets. Assets Measured at Fair Value on a Non-Recurring Basis We periodically review our intangible and other long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. Determination of recoverability is based on the lowest level of identifiable estimated undiscounted cash flows resulting from use of the asset and its eventual disposition. If not recoverable, an impairment loss would be calculated based on the excess of the carrying amount over the fair value. Management utilizes various valuation methods, including an income approach, a market approach and a cost approach, to estimate the fair value of intangible and other long-lived assets.

Description of Business and S_3

Description of Business and Summary of Significant Accounting Policies (Tables)	3 Months Ended
	Sep. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of estimated revenue expected to be recognized in the future related to performance obligations	The following table includes estimated revenue expected to be recognized in the future for backlog related performance obligations that are unsatisfied (or partially unsatisfied) as of September 29, 2018 : Less than 1 year 1-2 years Greater than 2 years Total Performance Obligations $384.8 $22.7 $0.4 $407.9
Schedule of changes in contract balances	The following table reflects the changes in contract balances for the three months ended September 30, 2018: Contract balances Balance sheet location September 29, 2018 June 30, 2018 Change Percentage Change Accounts receivable, net Accounts receivable, net $239.6 $197.1 $42.5 21.6% Deferred revenue and customer deposits Other current liabilities $2.6 $2.8 $(0.2) (7.1)%

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements (Tables)	3 Months Ended
	Sep. 29, 2018
Accounting Changes and Error Corrections [Abstract]
Condensed Consolidated Balance Sheet Line Items Which Reflect Adoption of Topic 606	Select condensed consolidated balance sheet line items, as if we had adopted Topic 606 in previous years, are summarized below as of the periods presented: June 30, 2018 Adjustments July 1, 2018 Assets: Accounts receivable, net $ 197.1 $ 0.6 $ 197.7 Inventories 153.6 (1.2 ) 152.4 Stockholders’ equity: Retained earnings $ 166.4 $ (0.6 ) $ 165.8

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Sep. 29, 2018
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted net income (loss) attributable to common stockholders per share	The following table sets forth the computation of basic and diluted net income attributable to common stockholders per share ( in millions, except per share data ): Three Months Ended September 29, 2018 September 30, 2017 Basic Earnings per Common Share Net income $ 47.4 $ 7.1 Less: Cumulative dividends on Series A Preferred Stock (0.2 ) (0.2 ) Less: Earnings allocated to Series A Preferred Stock (1.1 ) (0.2 ) Net income attributable to common stockholders - Basic $ 46.1 $ 6.7 Weighted average common shares outstanding including Series A Preferred Stock 64.6 63.2 Less: Weighted average Series A Preferred Stock (1.5 ) (1.5 ) Basic weighted average common shares outstanding 63.1 61.7 Net income per share attributable to common stockholders - Basic $ 0.73 $ 0.11 Diluted Earnings per Common Share Net income attributable to common stockholders - Basic $ 46.1 $ 6.7 Add: Earnings allocated to Series A Preferred Stock — 0.2 Add/Less: Unrealized (gain) loss on derivative liability on Series A Preferred Stock — (4.2 ) Add: Cumulative dividends on Series A Preferred Stock — 0.2 Net income attributable to common stockholders - Diluted (a) $ 46.1 $ 2.9 Weighted average common shares outstanding for basic earnings per common share 63.1 61.7 Effect of dilutive securities from 2015 Equity Incentive Plan 0.8 1.3 Effect of dilutive securities from Series A Preferred Stock — 1.5 Diluted weighted average common shares outstanding 63.9 64.5 Net income per share attributable to common stockholders - Diluted $ 0.72 $ 0.04 (a) For the three months ended September 30, 2017, our diluted earnings per share attributable to common stockholders is calculated using the if-converted method because it is more dilutive, whereas for the three months ended September 29, 2018, our diluted earnings per share attributable to common stockholders is calculated using the treasury stock method.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Sep. 29, 2018
Equity [Abstract]
Schedule of accumulated other comprehensive income (loss)	As of September 29, 2018 and June 30, 2018 , balances for the components of accumulated other comprehensive income (loss) were as follows ( in millions ): Foreign currency translation adjustments, net of tax Defined benefit obligation, net of tax (1) Unrealized gain (loss) on available-for-sale securities, net of tax Total Beginning balance as of June 30, 2018 $ 10.3 $ (2.3 ) $ (1.6 ) $ 6.4 Other comprehensive income 0.1 — 0.4 0.5 Ending balance as of September 29, 2018 $ 10.4 $ (2.3 ) $ (1.2 ) $ 6.9 (1) We evaluate the assumptions over the fair value of our defined benefit obligation annually and make changes as necessary.

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	3 Months Ended
	Sep. 29, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of components of inventories	The components of inventories were as follows ( in millions ): September 29, 2018 June 30, 2018 Finished goods $ 80.7 $ 98.2 Work in process 32.9 34.5 Raw materials and purchased parts 23.0 20.9 Inventories $ 136.6 $ 153.6
Schedule of components of prepayments and other current assets	The components of prepayments and other current assets were as follows ( in millions ): September 29, 2018 June 30, 2018 Capitalized manufacturing overhead $ 18.3 $ 20.5 Prepayments 22.3 19.5 Advances to contract manufacturers 13.7 14.0 Other current assets 16.3 11.0 Prepayments and other current assets $ 70.6 $ 65.0
Schedule of components of property, plant and equipment, net	The components of property, plant and equipment, net were as follows ( in millions ): September 29, 2018 June 30, 2018 Land $ 10.6 $ 10.6 Buildings and improvement 59.4 55.1 Machinery and equipment (1) 476.0 463.6 Computer equipment and software 26.5 26.3 Furniture and fixtures 2.9 2.2 Leasehold improvements 27.0 25.8 Construction in progress 59.9 52.6 662.3 636.2 Less: Accumulated depreciation (343.7 ) (329.3 ) Property, plant and equipment, net $ 318.6 $ 306.9 (1) In fiscal 2018, we started leasing equipment from a vendor and have accounted for the transaction as a capital lease. Included in the table above is our capital lease asset of $15.6 million , gross and depreciation expense of $6.7 million as of September 29, 2018 .
Schedule of components of other current liabilities	The components of other current liabilities were as follows (in millions) : September 29, 2018 June 30, 2018 Warranty accrual (1) $ 6.6 $ 6.6 Restructuring accrual and related charges (2) 1.6 1.9 Deferred revenue and customer deposits 2.6 2.8 Capital lease obligation (3) 5.4 7.3 Other current liabilities 4.8 3.5 Other current liabilities $ 21.0 $ 22.1 (1) Refer to “ Note 16. Commitments and Contingencies ” in the Notes to Unaudited Condensed Consolidated Financial Statements. (2) Refer to “ Note 13. Restructuring and Related Charges ” in the Notes to Unaudited Condensed Consolidated Financial Statements. (3) As of September 29, 2018 , an amount of $1.6 million related to a capital lease was recorded in accounts payable on the condensed consolidated balance sheet. Refer to “ Note 16. Commitments and Contingencies ” in the Notes to Unaudited Condensed Consolidated Financial Statements.
Schedule of components of other non-current liabilities	The components of other non-current liabilities were as follows ( in millions ): September 29, 2018 June 30, 2018 Asset retirement obligation $ 2.7 $ 2.7 Pension and related accrual 3.7 3.5 Deferred rent 2.5 2.6 Unrecognized tax benefit 9.0 6.1 Capital lease obligation (1) — 0.4 Other non-current liabilities 0.9 3.7 Other non-current liabilities $ 18.8 $ 19.0 (1) Refer to “ Note 16. Commitments and Contingencies ” in the Notes to Unaudited Condensed Consolidated Financial Statements.

Cash, Cash Equivalents, and S_2

Cash, Cash Equivalents, and Short-term Investments (Tables)	3 Months Ended
	Sep. 29, 2018
Cash and Cash Equivalents [Abstract]
Schedule of cash, cash equivalents and short-term investments	The following table summarizes our cash, cash equivalents, and short-term investments by category for the periods presented ( in millions ): Amortized Gross Gross Fair Value September 29, 2018: Cash $ 149.9 $ — $ — $ 149.9 Cash equivalents: Commercial paper 3.6 — — 3.6 Money market funds 286.5 — — 286.5 U.S. Treasury 19.4 — — 19.4 Total cash and cash equivalents $ 459.4 $ — $ — $ 459.4 Short-term investments: Commercial paper $ 6.7 $ — $ — $ 6.7 Asset-backed securities 58.5 — (0.2 ) 58.3 Corporate debt securities 202.4 0.1 (1.1 ) 201.4 Municipal bonds 0.4 — — 0.4 Mortgage-backed securities 3.0 — — 3.0 Foreign government bonds 5.1 — — 5.1 Total short-term investments $ 276.1 $ 0.1 $ (1.3 ) $ 274.9 June 30, 2018: Cash $ 103.6 $ — $ — $ 103.6 Cash equivalents: Certificates of deposit 3.0 — — 3.0 Commercial paper 112.1 — — 112.1 Money market funds 0.8 — — 0.8 U.S. Treasury securities 143.6 — — 143.6 U.S. Agency securities 34.2 — — 34.2 Total cash and cash equivalents $ 397.3 $ — $ — $ 397.3 Short-term investments: Certificates of deposit $ 7.5 $ — $ — $ 7.5 Commercial paper 10.5 — — 10.5 Asset-backed securities 68.0 — (0.2 ) 67.8 Corporate debt securities 220.6 0.1 (1.5 ) 219.2 Municipal bonds 1.6 — — 1.6 Mortgage-backed securities 4.2 — — 4.2 Foreign government bonds 3.4 — — 3.4 Total short-term investments $ 315.8 $ 0.1 $ (1.7 ) $ 314.2
Summary of unrealized losses on cash equivalents and short-term investments	The following table summarizes unrealized losses on our cash equivalents and short-term investments by category and length of time the investment has been in a continuous unrealized loss position as of the periods presented (in millions) : Less than 12 months 12 Months or Greater Total Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses September 29, 2018: Commercial paper $ 6.1 $ — $ — $ — $ 6.1 $ — Asset-backed securities 48.4 (0.2 ) 8.5 — 56.9 (0.2 ) Corporate debt securities 113.3 (0.8 ) 46.9 (0.3 ) 160.2 (1.1 ) Mortgage-backed securities 2.8 — — — 2.8 — Foreign government bonds 4.1 — — — 4.1 — Total $ 174.7 $ (1.0 ) $ 55.4 $ (0.3 ) $ 230.1 $ (1.3 ) June 30, 2018: Certificates of deposit $ 5.4 $ — $ — $ — $ 5.4 $ — Commercial paper 8.5 — — — 8.5 — Asset-backed securities 66.6 (0.2 ) 0.3 — 66.9 (0.2 ) Corporate debt securities 188.6 (1.5 ) 2.0 — 190.6 (1.5 ) Municipal bonds 0.6 — — — 0.6 — U.S. Agency securities 4.0 — — — 4.0 — Foreign government bonds 3.4 — — — 3.4 — Total $ 277.1 $ (1.7 ) $ 2.3 $ — $ 279.4 $ (1.7 )
Classification of investments in debt securities by contractual maturities	The following table classifies our investments in debt securities by contractual maturities ( in millions ): September 29, 2018 June 30, 2018 Amortized Cost Fair Value Amortized Cost Fair Value Due in 1 year $ 150.0 $ 149.5 $ 150.1 $ 149.6 Due in 1 year through 5 years 119.4 118.7 157.2 156.1 Due in 5 years through 10 years 4.9 4.9 6.1 6.1 Due after 10 years 1.8 1.8 2.4 2.4 $ 276.1 $ 274.9 $ 315.8 $ 314.2

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Sep. 29, 2018
Fair Value Disclosures [Abstract]
Summary of financial assets and liabilities measured at fair value on a recurring basis	Financial assets and liabilities measured at fair value on a recurring basis are summarized below ( in millions ): Level 1 Level 2 Level 3 Total September 29, 2018: Assets: Cash equivalents: Commercial paper $ — $ 3.6 $ — $ 3.6 Money market funds 286.5 — — 286.5 U.S. Treasury 19.4 — — 19.4 Short-term investments: Commercial paper — 6.7 — 6.7 Asset-backed securities — 58.3 — 58.3 Corporate debt securities — 201.4 — 201.4 Municipal bonds — 0.4 — 0.4 Mortgage-backed securities — 3.0 — 3.0 Foreign government bonds — 5.1 — 5.1 Total assets $ 305.9 $ 278.5 $ — $ 584.4 Other accrued liabilities: Derivative liability $ — $ — $ 54.5 $ 54.5 Acquisition contingencies — — 2.7 2.7 Total other accrued liabilities $ — $ — $ 57.2 $ 57.2 Level 1 Level 2 Level 3 Total June 30, 2018: Assets: Cash equivalents: Certificates of deposit $ — $ 3.0 $ — $ 3.0 Commercial paper — 112.1 — 112.1 Money market funds 0.8 — — 0.8 U.S. Treasury securities 143.6 — — 143.6 U.S. Agency securities — 34.2 — 34.2 Short-term investments: Certificates of deposit — 7.5 — 7.5 Commercial paper — 10.5 — 10.5 Asset-backed securities — 67.8 — 67.8 Corporate debt securities — 219.2 — 219.2 Municipal bonds — 1.6 — 1.6 Mortgage-backed securities — 4.2 — 4.2 Foreign government bonds — 3.4 — 3.4 Total assets $ 144.4 $ 463.5 $ — $ 607.9 Other accrued liabilities: Derivative liability $ — $ — $ 52.4 $ 52.4 Acquisition contingencies — — 2.7 2.7 Total other accrued liabilities $ — $ — $ 55.1 $ 55.1

Convertible Senior Notes (Table

Convertible Senior Notes (Tables)	3 Months Ended
	Sep. 29, 2018
Debt Disclosure [Abstract]
Components of 2024 Notes	The 2024 Notes consisted of the following components as of the periods presented ( in millions ): Liability component: September 29, 2018 June 30, 2018 Principal $ 450.0 $ 450.0 Unamortized debt discount (111.5 ) (115.8 ) Net carrying amount of the liability component $ 338.5 $ 334.2
Interest Expense on Convertible Debt	The following table sets forth interest expense information related to the 2024 Notes for the periods presented (in millions, except percentages) : Three Months Ended (in millions, except percentages) September 29, 2018 September 30, 2017 Contractual interest expense $ 0.3 $ 0.3 Amortization of the debt discount 4.3 4.1 Total interest expense $ 4.6 $ 4.4 Effective interest rate on the liability component 5.4 % 5.4 %

Derivative Liability (Tables)

Derivative Liability (Tables)	3 Months Ended
	Sep. 29, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Reconciliation of fair value of embedded derivative	The following table provides a reconciliation of the fair value of the embedded derivative for the Series A Preferred Stock for the three months ended September 29, 2018 and September 30, 2017 ( in millions ): Three Months Ended September 29, 2018 September 30, 2017 Balance as of beginning of period $ 52.4 $ 51.6 Unrealized (gain) loss on the Series A Preferred Stock derivative liability 2.1 (4.2 ) Balance as of end of period $ 54.5 $ 47.4

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	3 Months Ended
	Sep. 29, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in goodwill	The following table presents the changes in goodwill by our reportable segments during the three months ended September 29, 2018 ( in millions) : Optical Communications Commercial Lasers Total Balance as of beginning of period $ 5.9 $ 5.4 $ 11.3 Foreign currency translation adjustment — — — Balance as of end of period $ 5.9 $ 5.4 $ 11.3 The following table presents the changes in goodwill by our reportable segments during the three months ended September 30, 2017 ( in millions) : Optical Communications Commercial Lasers Total Balance as of beginning of period $ 5.9 $ 5.5 $ 11.4 Foreign currency translation adjustment 0.2 (0.1 ) 0.1 Balance as of end of period $ 6.1 $ 5.4 $ 11.5
Acquired developed technology and other intangibles	The following tables present details of our acquired developed technologies and other intangibles as of the periods presented ( in millions ): September 29, 2018: Gross Carrying Amount Accumulated Amortization Net Acquired developed technologies $ 105.6 $ (99.3 ) $ 6.3 Other intangibles 7.0 (7.0 ) — Total intangible assets $ 112.6 $ (106.3 ) $ 6.3 June 30, 2018: Gross Carrying Amount Accumulated Amortization Net Acquired developed technologies $ 105.5 $ (98.5 ) $ 7.0 Other intangibles 7.0 (7.0 ) — Total intangible assets $ 112.5 $ (105.5 ) $ 7.0
Details of amortization expense	The following table presents details of amortization for the periods presented (in millions ): Three Months Ended September 29, 2018 September 30, 2017 Cost of sales $ 0.8 $ 0.8 Total $ 0.8 $ 0.8
Estimated future amortization expense	Based on the carrying amount of acquired developed technologies as of September 29, 2018 , and assuming no future impairment of the underlying assets, the estimated future amortization is as follows (in millions): Fiscal Years Remainder of 2019 $ 2.2 2020 2.9 2021 0.5 2022 0.5 Thereafter 0.2 Total amortization $ 6.3

Restructuring and Related Cha_2

Restructuring and Related Charges (Tables)	3 Months Ended
	Sep. 29, 2018
Restructuring and Related Activities [Abstract]
Summary of activity of restructuring and related charges	The following table summarizes the activity of restructuring and related charges during the three months ended September 29, 2018 and September 30, 2017 ( in millions ): Three Months Ended September 29, 2018 September 30, 2017 Balance as of beginning of period $ 1.9 $ 3.8 Charges 1.3 2.9 Payments (1.6 ) (5.4 ) Balance as of end of period $ 1.6 $ 1.3

Stock-Based Compensation and _2

Stock-Based Compensation and Stock Plans (Tables)	3 Months Ended
	Sep. 29, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of impact on results of operations of recording stock-based compensation by function	The impact on our results of operations of recording stock-based compensation by function for the three months ended September 29, 2018 and September 30, 2017 was as follows (in millions) : Three Months Ended September 29, 2018 September 30, 2017 Cost of sales $ 3.3 $ 2.7 Research and development 2.8 3.1 Selling, general and administrative 4.7 3.5 $ 10.8 $ 9.3
Summary of awards activity	The following table summarizes our awards activity for the three months ended September 29, 2018 (in millions, except per share amounts) : Restricted Stock Units Restricted Stock Awards Performance Stock Units Number of Shares Weighted-Average Grant Date Fair Value per Share Number of Shares Weighted-Average Grant Date Fair Value per Share Number of Shares (1) Weighted-Average Grant Date Fair Value per Share Unvested balance as of beginning of period 1.7 $ 43.1 0.1 $ 32.5 0.2 $ 52.0 Granted 0.7 67.8 — — — — Vested (0.5 ) 38.4 — — (0.1 ) 52.0 Canceled (0.1 ) 49.6 — — — — Unvested balance as of end of period 1.8 $ 55.2 0.1 $ 32.5 0.1 $ — (1) In fiscal 2018, we granted 0.1 million PSUs to senior members of our management team subject to revenue performance condition. The number of awards granted in fiscal 2018 represented 100% of target goal; under the terms of the awards, the recipient could earn between 0% and 200% of the original grant. The performance condition was achieved in fiscal 2018. During the three months ended September 29, 2018, our board of directors approved an increase in the original number of PSUs based on the actual achievement.
Summary of awards available for grant	A summary of awards available for grant is as follows (in millions) : Awards Available for Grant Balance as of beginning of period 5.6 Granted (0.7 ) Canceled 0.1 Balance as of end of period 5.0
Schedule of assumptions used to estimate fair value	During the three months ended September 29, 2018 and September 30, 2017 , the assumptions used to estimate the fair value of the 2015 Purchase Plan shares to be issued were as follows: September 29, 2018 September 30, 2017 Expected term (years) 0.5 0.5 Expected volatility 58.8 % 53.0 % Risk-free interest rate 2.02 % 1.02 % Dividend yield — % — %

Commitments and Contingencies (

Commitments and Contingencies (Tables)	3 Months Ended
	Sep. 29, 2018
Commitments and Contingencies Disclosure [Abstract]
Schedule of future minimum annual lease payments under non-cancellable operating leases	As of September 29, 2018 , the future minimum annual lease payments under non-cancellable operating leases were as follows ( in millions ): Fiscal Years Remainder of 2019 $ 8.8 2020 6.5 2021 5.1 2022 3.4 2023 2.4 Thereafter 1.8 Total minimum operating lease payments $ 28.0
Schedule of future minimum annual lease payments under capital lease	As of September 29, 2018 the future minimum annual lease payments under our capital lease were as follows ( in millions ): Fiscal Years Remainder of 2019 $ 6.7 2020 0.4 Total minimum capital lease payments $ 7.1 Less: amount representing interest $ (0.1 ) Present value of capital lease obligation $ 7.0
Schedule of future interest and principal payments related to 2024 Notes	The future interest and principal payments related to the 2024 Notes are as follows as of September 29, 2018 : Fiscal Years Remainder of 2019 $ 0.6 2020 1.1 2021 1.1 2022 1.1 2023 1.1 Thereafter 451.2 Total 2024 Notes payments $ 456.2
Schedule of changes in warranty reserve	The following table presents the changes in our warranty reserve during the three months ended September 29, 2018 and September 30, 2017 ( in millions ): Three Months Ended September 29, 2018 September 30, 2017 Balance as of beginning of period $ 6.6 $ 9.7 Provision for warranty 1.2 1.0 Utilization of reserve (1.2 ) (1.3 ) Balance as of end of period $ 6.6 $ 9.4

Operating Segments and Geogra_2

Operating Segments and Geographic Information (Tables)	3 Months Ended
	Sep. 29, 2018
Segment Reporting [Abstract]
Schedule of information on reportable segments	Information on reportable segments utilized by our CODM is as follows ( in millions) : Three Months Ended September 29, 2018 September 30, 2017 Net revenue: OpComms $ 310.1 $ 207.9 Lasers 44.0 35.3 Net revenue $ 354.1 $ 243.2 Gross profit: OpComms 124.9 72.1 Lasers 17.7 10.6 Total segment gross profit 142.6 82.7 Unallocated corporate items: Stock-based compensation (3.3 ) (2.7 ) Amortization of intangibles (0.8 ) (0.8 ) Other charges (1) (12.5 ) (10.7 ) Gross profit $ 126.0 $ 68.5 (1) “Other charges” of unallocated corporate items for the three months ended September 29, 2018 primarily include set-up costs of our facility in Thailand, including costs of transferring product lines to Thailand of $12.7 million . During the three months ended September 30, 2017 , “other charges” of unallocated corporate items primarily consisted of set-up costs of our facility in Thailand of $3.1 million , as well as inventory write-downs due to canceled programs not allocated to the segments of $7.0 million .
Schedule of concentration risks	During the three months ended September 29, 2018 and September 30, 2017 , net inventory purchased from a single contract manufacturer which represented 10% or greater of total net purchases is summarized as follows: Three Months Ended September 29, 2018 September 30, 2017 Vendor A 51.5 % 44.9 % Vendor B 25.1 % 25.7 % Vendor C * 10.9 % *Represents less than 10% of total net purchases The table below discloses our total net revenue attributable to each of our two reportable segments. In addition, it discloses the percentage of our total net revenue attributable to our product offerings which serve the Telecom, Datacom, and Consumer and Industrial markets which accounted for 10% or more of our total net revenue during the periods presented: Three Months Ended September 29, 2018 September 30, 2017 OpComms: $ 310.1 $ 207.9 Telecom 142.9 110.4 Datacom 34.2 45.2 Consumer and Industrial 133.0 52.3 Lasers $ 44.0 $ 35.3 During the three months ended September 29, 2018 and September 30, 2017 , net revenue generated from a single customer which represented 10% or greater of total net revenue is summarized as follows: Three Months Ended September 29, 2018 September 30, 2017 Customer A 30.5 % 16.3 % Customer B 15.0 % * Customer C 13.0 % 14.2 % Customer D * 10.4 % *Represents less than 10% of total net revenue
Schedule of revenue by geographic region	The following table presents net revenue by the three geographic regions we operate in and net revenue from countries that represented 10% or more of our total net revenue (in millions, except percentage data): Three Months Ended September 29, 2018 September 30, 2017 Net revenue: Americas: United States $ 21.9 6.2 % $ 33.6 13.8 % Mexico 56.3 15.9 24.8 10.3 Other Americas 0.9 0.3 2.2 0.9 Total Americas $ 79.1 22.4 % $ 60.6 25.0 % Asia-Pacific: Hong Kong $ 65.5 18.5 % $ 48.9 20.1 % Japan 36.1 10.2 34.1 14.0 South Korea 70.0 19.8 10.9 4.5 Other Asia-Pacific 74.1 20.9 63.3 26.0 Total Asia-Pacific $ 245.7 69.4 % $ 157.2 64.6 % EMEA $ 29.3 8.2 % $ 25.4 10.4 % Total net revenue $ 354.1 $ 243.2
Schedule of long-lived assets by geographic region	Long-lived assets, namely net property, plant and equipment were identified based on the physical location of the assets in the corresponding geographic areas (in millions) : As of September 29, 2018 June 30, 2018 Property, Plant and Equipment, net United States $ 103.6 $ 97.6 China 62.1 70.0 Thailand 131.3 107.4 Other countries 21.6 31.9 Total long-lived assets $ 318.6 $ 306.9

Description of Business and S_4

Description of Business and Summary of Significant Accounting Policies - Merger Agreement (Details)	3 Months Ended	9 Months Ended
	Sep. 29, 2018USD ($)	Dec. 11, 2018USD ($)$ / shares	Mar. 11, 2018USD ($)
Term Loan Credit Facility
Business Acquisition [Line Items]
Senior secured term loan facility	$ 500,000,000
Ticking fee expense	400,000
Debt issuance costs capitalized	$ 900,000
Term Loan Credit Facility | 31st Day Following Allocation
Business Acquisition [Line Items]
Ticking fee	1.25%
Term Loan Credit Facility | 61st Day Following Allocation
Business Acquisition [Line Items]
Ticking fee	2.50%
Forecast | Oclaro, Inc.
Business Acquisition [Line Items]
Total transaction consideration as of date of the Merger Agreement		$ 1,800,000,000
Percentage of interest owned by Oclaro shareholders of combined company		16.00%
Oclaro, Inc.
Business Acquisition [Line Items]
Maximum borrowing capacity			$ 550,000,000
Oclaro, Inc. | Forecast
Business Acquisition [Line Items]
Exchange for consideration, cash paid for each share of Oclaro common stock (usd per share) | $ / shares		$ 5.60
Exchange for consideration, shares paid paid for each share of Oclaro common stock		0.0636
Termination fee if terms of Merger Agreement not met		$ 80,000,000
Total transaction consideration		1,600,000,000
Lumentum common stock		600,000,000
New debt incurred in total transaction consideration		$ 500,000,000

Description of Business and S_5

Description of Business and Summary of Significant Accounting Policies - Performance Obligations (Details) $ in Millions	Sep. 29, 2018USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Performance Obligations	$ 407.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-09-30
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Performance Obligations	$ 384.8
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period	9 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-06-30
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Performance Obligations	$ 22.7
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-06-30
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Performance Obligations	$ 0.4
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period

Description of Business and S_6

Description of Business and Summary of Significant Accounting Policies - Warranty (Details)	3 Months Ended
	Sep. 29, 2018
Product Warranty Liability [Line Items]
Warranty term	12 months
Minimum
Product Warranty Liability [Line Items]
Warranty term	6 months
Maximum
Product Warranty Liability [Line Items]
Warranty term	5 years

Description of Business and S_7

Description of Business and Summary of Significant Accounting Policies - Schedule of Changes in Contract Balances (Details) $ in Millions	3 Months Ended
	Sep. 29, 2018USD ($)
Accounts receivable, net
Accounts receivable, net, beginning of period	$ 197.1
Accounts receivable, net, end of period	239.6
Change	$ 42.5
Percentage Change	21.60%
Deferred revenue and customer deposits
Deferred revenue and customer deposits, beginning of period	$ 2.8
Deferred revenue and customer deposits, end of period	2.6
Change	$ (0.2)
Percentage Change	(7.10%)
Revenue recognized for satisfaction of performance obligation over time	$ 0.4

Recently Issued Accounting Pr_3

Recently Issued Accounting Pronouncements - Condensed Consolidated Balance Sheet Line Items Which Reflect Adoption of Topic 606 (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jul. 01, 2018	Jun. 30, 2018
Assets:
Accounts receivable, net	$ 239.6	$ 197.7	$ 197.1
Inventories	136.6	152.4	153.6
Stockholders’ equity:
Retained earnings	$ 213	165.8	166.4
Before Adjustments
Assets:
Accounts receivable, net			197.1
Inventories			153.6
Stockholders’ equity:
Retained earnings			$ 166.4
Adjustments | Accounting Standards Update 2014-09
Assets:
Accounts receivable, net		0.6
Inventories		(1.2)
Stockholders’ equity:
Retained earnings		$ (0.6)

Recently Issued Accounting Pr_4

Recently Issued Accounting Pronouncements - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash outflows for operating activities	$ (57.2)	$ (9.7)
Financing activities	4.6	$ (0.3)
ASU 2016-15 | Settlement of 2024 Notes
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash outflows for operating activities	137.6
Financing activities	$ 312.4

Earnings Per Share - Computatio

Earnings Per Share - Computation of Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		3 Months Ended
		Sep. 29, 2018	Sep. 30, 2017
Basic Earnings per Common Share
Net income		$ 47.4	$ 7.1
Less: Cumulative dividends on Series A Preferred Stock		(0.2)	(0.2)
Less: Earnings allocated to Series A Preferred Stock		(1.1)	(0.2)
Net income attributable to common stockholders - Basic		$ 46.1	$ 6.7
Weighted average common shares outstanding including Series A Preferred Stock (in shares)		64.6	63.2
Less: Weighted average Series A Preferred Stock (in shares)		(1.5)	(1.5)
Basic weighted average common shares outstanding (in shares)		63.1	61.7
Net income (loss) per share attributable to common stockholders - Basic (usd per share)		$ 0.73	$ 0.11
Diluted Earnings per Common Share
Net income attributable to common stockholders - Basic		$ 46.1	$ 6.7
Add: Earnings allocated to Series A Preferred Stock		0	0.2
Add/Less: Unrealized (gain) loss on derivative liability on Series A Preferred Stock		0	(4.2)
Add: Cumulative dividends on Series A Preferred Stock		0	0.2
Net income attributable to common stockholders - Diluted	[1]	$ 46.1	$ 2.9
Weighted average common shares outstanding for basic earnings per common share (in shares)		63.1	61.7
Effect of dilutive securities from 2015 Equity Incentive Plan (in shares)		0.8	1.3
Effect of diluted securities from Series A Preferred Stock (in shares)		0	1.5
Diluted weighted average common shares outstanding (in shares)		63.9	64.5
Net income (loss) per share attributable to common stockholders - Diluted (usd per share)		$ 0.72	$ 0.04
[1]	(a) For the three months ended September 30, 2017, our diluted earnings per share attributable to common stockholders is calculated using the if-converted method because it is more dilutive, whereas for the three months ended September 29, 2018, our diluted earnings per share attributable to common stockholders is calculated using the treasury stock method.

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - Convertible Debt - 2024 Notes - USD ($)	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, aggregate principal amount	$ 450,000,000	$ 450,000,000	$ 450,000,000
Debt, stated interest rate	0.25%		0.25%
Conversion price (usd per share)			$ 60.62

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) $ in Millions	3 Months Ended
	Sep. 29, 2018USD ($)
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ 926.1
Other comprehensive income	0.5
Balance at the end of the period	983.5
Foreign currency translation adjustments, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	10.3
Other comprehensive income	0.1
Balance at the end of the period	10.4
Defined benefit obligation, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(2.3)
Other comprehensive income	0
Balance at the end of the period	(2.3)
Unrealized gain (loss) on available-for-sale securities, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(1.6)
Other comprehensive income	0.4
Balance at the end of the period	(1.2)
Total
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	6.4
Balance at the end of the period	$ 6.9

Asset Acquisition (Details)

Asset Acquisition (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Mar. 30, 2018
Asset Acquisition [Abstract]
Required cash payment upon completion of certain milestones related to purchase of equipment			$ 5.3
Payments for manufacturing equipment	$ 0.7	$ 0

Balance Sheet Details - Account

Balance Sheet Details - Accounts Receivable Allowances (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts receivable allowance	$ 2.1	$ 2.6

Balance Sheet Details - Invento

Balance Sheet Details - Inventories (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jul. 01, 2018	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Finished goods	$ 80.7		$ 98.2
Work in process	32.9		34.5
Raw materials and purchased parts	23		20.9
Inventories	$ 136.6	$ 152.4	$ 153.6

Balance Sheet Details - Prepaym

Balance Sheet Details - Prepayments and Other Current Assets (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Capitalized manufacturing overhead	$ 18.3	$ 20.5
Prepayments	22.3	19.5
Advances to contract manufacturers	13.7	14
Other current assets	16.3	11
Prepayments and other current assets	$ 70.6	$ 65

Balance Sheet Details - Propert

Balance Sheet Details - Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Jun. 30, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 662.3		$ 636.2
Less: Accumulated depreciation	(343.7)		(329.3)
Property, plant and equipment, net	318.6		306.9
Depreciation expense	19.7	$ 16.7
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	10.6		10.6
Buildings and improvement
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	59.4		55.1
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	476		463.6
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	26.5		26.3
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	2.9		2.2
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	27		25.8
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	59.9		$ 52.6
Capital lease assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	15.6
Less: Accumulated depreciation	$ (6.7)

Balance Sheet Details - Other C

Balance Sheet Details - Other Current Liabilities (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018	Sep. 30, 2017	Jul. 01, 2017
Debt Instrument [Line Items]
Warranty accrual	$ 6.6	$ 6.6
Restructuring accrual and related charges	1.6	1.9	$ 1.3	$ 3.8
Deferred revenue and customer deposits	2.6	2.8
Capital lease obligation	5.4	7.3
Other current liabilities	4.8	3.5
Other current liabilities	21	$ 22.1
Accounts Payable
Debt Instrument [Line Items]
Capital lease obligation	$ 1.6

Balance Sheet Details - Other N

Balance Sheet Details - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Asset retirement obligation	$ 2.7	$ 2.7
Pension and related accrual	3.7	3.5
Deferred rent	2.5	2.6
Unrecognized tax benefit	9	6.1
Capital lease obligation	0	0.4
Other non-current liabilities	0.9	3.7
Other non-current liabilities	$ 18.8	$ 19

Cash, Cash Equivalents, and S_3

Cash, Cash Equivalents, and Short-term Investments - Summary of Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018	Sep. 30, 2017	Jul. 01, 2017
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 459.4	$ 397.3	$ 150.8	$ 272.9
Short-term investments:
Amortized Cost	276.1	315.8
Gross Unrealized Gains	0.1	0.1
Gross Unrealized Losses	(1.3)	(1.7)
Fair Value	274.9	314.2
Certificates of deposit
Short-term investments:
Amortized Cost		7.5
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		7.5
Commercial paper
Short-term investments:
Amortized Cost	6.7	10.5
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	6.7	10.5
Asset-backed securities
Short-term investments:
Amortized Cost	58.5	68
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(0.2)	(0.2)
Fair Value	58.3	67.8
Corporate debt securities
Short-term investments:
Amortized Cost	202.4	220.6
Gross Unrealized Gains	0.1	0.1
Gross Unrealized Losses	(1.1)	(1.5)
Fair Value	201.4	219.2
Municipal bonds
Short-term investments:
Amortized Cost	0.4	1.6
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	0.4	1.6
Mortgage-backed securities
Short-term investments:
Amortized Cost	3	4.2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	3	4.2
Foreign government bonds
Short-term investments:
Amortized Cost	5.1	3.4
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	5.1	3.4
Cash
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	149.9	103.6
Certificates of deposit
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents		3
Commercial paper
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	3.6	112.1
Money market funds
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	286.5	0.8
U.S. Treasury
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents	$ 19.4	143.6
U.S. Agency securities
Cash and Cash Equivalents [Line Items]
Total cash and cash equivalents		$ 34.2

Cash, Cash Equivalents, and S_4

Cash, Cash Equivalents, and Short-term Investments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Investments, Debt and Equity Securities [Abstract]
Interest and other income (expense), net	$ (2.4)	$ (3.4)
income on short-term investments and cash equivalents	$ 2.7	$ 1.5

Cash, Cash Equivalents, and S_5

Cash, Cash Equivalents, and Short-term Investments - Summary of Unrealized Losses (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Fair Value
Less than 12 months	$ 174.7	$ 277.1
12 Months or Greater	55.4	2.3
Total	230.1	279.4
Unrealized Losses
Less than 12 months	(1)	(1.7)
12 Months or Greater	(0.3)	0
Total	(1.3)	(1.7)
Certificates of deposit
Fair Value
Less than 12 months		5.4
12 Months or Greater		0
Total		5.4
Unrealized Losses
Less than 12 months		0
12 Months or Greater		0
Total		0
Commercial paper
Fair Value
Less than 12 months	6.1	8.5
12 Months or Greater	0	0
Total	6.1	8.5
Unrealized Losses
Less than 12 months	0	0
12 Months or Greater	0	0
Total	0	0
Asset-backed securities
Fair Value
Less than 12 months	48.4	66.6
12 Months or Greater	8.5	0.3
Total	56.9	66.9
Unrealized Losses
Less than 12 months	(0.2)	(0.2)
12 Months or Greater	0	0
Total	(0.2)	(0.2)
Corporate debt securities
Fair Value
Less than 12 months	113.3	188.6
12 Months or Greater	46.9	2
Total	160.2	190.6
Unrealized Losses
Less than 12 months	(0.8)	(1.5)
12 Months or Greater	(0.3)	0
Total	(1.1)	(1.5)
Mortgage-backed securities
Fair Value
Less than 12 months	2.8
12 Months or Greater	0
Total	2.8
Unrealized Losses
Less than 12 months	0
12 Months or Greater	0
Total	0
Municipal bonds
Fair Value
Less than 12 months		0.6
12 Months or Greater		0
Total		0.6
Unrealized Losses
Less than 12 months		0
12 Months or Greater		0
Total		0
U.S. Agency securities
Fair Value
Less than 12 months		4
12 Months or Greater		0
Total		4
Unrealized Losses
Less than 12 months		0
12 Months or Greater		0
Total		0
Foreign government bonds
Fair Value
Less than 12 months	4.1	3.4
12 Months or Greater	0	0
Total	4.1	3.4
Unrealized Losses
Less than 12 months	0	0
12 Months or Greater	0	0
Total	$ 0	$ 0

Cash, Cash Equivalents, and S_6

Cash, Cash Equivalents, and Short-term Investments - Investments in Debt Securities by Contractual Maturities (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Amortized Cost
Due in 1 year	$ 150	$ 150.1
Due in 1 year through 5 years	119.4	157.2
Due in 5 years through 10 years	4.9	6.1
Due after 10 years	1.8	2.4
Total	276.1	315.8
Fair Value
Due in 1 year	149.5	149.6
Due in 1 year through 5 years	118.7	156.1
Due in 5 years through 10 years	4.9	6.1
Due after 10 years	1.8	2.4
Total	$ 274.9	$ 314.2

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - Private Company Acquisition - USD ($) $ in Millions	1 Months Ended
	Feb. 28, 2017	Sep. 29, 2018
Business Acquisition [Line Items]
Total purchase consideration	$ 8.7
Estimated likelihood of achieving production targets	90.00%
Contingent consideration, cash payment that could result if production targets achieved		$ 3
Period following acquisition date	12 months

Fair Value Measurements - Measu

Fair Value Measurements - Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Assets:
Short-term investments	$ 274.9	$ 314.2
Certificates of deposit
Assets:
Short-term investments		7.5
Commercial paper
Assets:
Short-term investments	6.7	10.5
Asset-backed securities
Assets:
Short-term investments	58.3	67.8
Corporate debt securities
Assets:
Short-term investments	201.4	219.2
Municipal bonds
Assets:
Short-term investments	0.4	1.6
Mortgage-backed securities
Assets:
Short-term investments	3	4.2
Foreign government bonds
Assets:
Short-term investments	5.1	3.4
Recurring basis
Assets:
Total assets	584.4	607.9
Other accrued liabilities:
Derivative liability	54.5	52.4
Acquisition contingencies	2.7	2.7
Total other accrued liabilities	57.2	55.1
Recurring basis | Certificates of deposit
Assets:
Short-term investments		7.5
Recurring basis | Commercial paper
Assets:
Short-term investments	6.7	10.5
Recurring basis | Asset-backed securities
Assets:
Short-term investments	58.3	67.8
Recurring basis | Corporate debt securities
Assets:
Short-term investments	201.4	219.2
Recurring basis | Municipal bonds
Assets:
Short-term investments	0.4	1.6
Recurring basis | Mortgage-backed securities
Assets:
Short-term investments	3	4.2
Recurring basis | Foreign government bonds
Assets:
Short-term investments	5.1	3.4
Recurring basis | Certificates of deposit
Assets:
Cash equivalents		3
Recurring basis | Commercial paper
Assets:
Cash equivalents	3.6	112.1
Recurring basis | Money market funds
Assets:
Cash equivalents	286.5	0.8
Recurring basis | U.S. Treasury
Assets:
Cash equivalents	19.4	143.6
Recurring basis | U.S. Agency securities
Assets:
Cash equivalents		34.2
Recurring basis | Level 1
Assets:
Total assets	305.9	144.4
Other accrued liabilities:
Derivative liability	0	0
Acquisition contingencies	0	0
Total other accrued liabilities	0	0
Recurring basis | Level 1 | Certificates of deposit
Assets:
Short-term investments		0
Recurring basis | Level 1 | Commercial paper
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Asset-backed securities
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Corporate debt securities
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Municipal bonds
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Mortgage-backed securities
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Foreign government bonds
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Certificates of deposit
Assets:
Cash equivalents		0
Recurring basis | Level 1 | Commercial paper
Assets:
Cash equivalents	0	0
Recurring basis | Level 1 | Money market funds
Assets:
Cash equivalents	286.5	0.8
Recurring basis | Level 1 | U.S. Treasury
Assets:
Cash equivalents	19.4	143.6
Recurring basis | Level 1 | U.S. Agency securities
Assets:
Cash equivalents		0
Recurring basis | Level 2
Assets:
Total assets	278.5	463.5
Other accrued liabilities:
Derivative liability	0	0
Acquisition contingencies	0	0
Total other accrued liabilities	0	0
Recurring basis | Level 2 | Certificates of deposit
Assets:
Short-term investments		7.5
Recurring basis | Level 2 | Commercial paper
Assets:
Short-term investments	6.7	10.5
Recurring basis | Level 2 | Asset-backed securities
Assets:
Short-term investments	58.3	67.8
Recurring basis | Level 2 | Corporate debt securities
Assets:
Short-term investments	201.4	219.2
Recurring basis | Level 2 | Municipal bonds
Assets:
Short-term investments	0.4	1.6
Recurring basis | Level 2 | Mortgage-backed securities
Assets:
Short-term investments	3	4.2
Recurring basis | Level 2 | Foreign government bonds
Assets:
Short-term investments	5.1	3.4
Recurring basis | Level 2 | Certificates of deposit
Assets:
Cash equivalents		3
Recurring basis | Level 2 | Commercial paper
Assets:
Cash equivalents	3.6	112.1
Recurring basis | Level 2 | Money market funds
Assets:
Cash equivalents	0	0
Recurring basis | Level 2 | U.S. Treasury
Assets:
Cash equivalents	0	0
Recurring basis | Level 2 | U.S. Agency securities
Assets:
Cash equivalents		34.2
Recurring basis | Level 3
Assets:
Total assets	0	0
Other accrued liabilities:
Derivative liability	54.5	52.4
Acquisition contingencies	2.7	2.7
Total other accrued liabilities	57.2	55.1
Recurring basis | Level 3 | Certificates of deposit
Assets:
Short-term investments		0
Recurring basis | Level 3 | Commercial paper
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Asset-backed securities
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Corporate debt securities
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Municipal bonds
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Mortgage-backed securities
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Foreign government bonds
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Certificates of deposit
Assets:
Cash equivalents		0
Recurring basis | Level 3 | Commercial paper
Assets:
Cash equivalents	0	0
Recurring basis | Level 3 | Money market funds
Assets:
Cash equivalents	0	0
Recurring basis | Level 3 | U.S. Treasury
Assets:
Cash equivalents	$ 0	0
Recurring basis | Level 3 | U.S. Agency securities
Assets:
Cash equivalents		$ 0

Non-Controlling Interest Rede_2

Non-Controlling Interest Redeemable Convertible Preferred Stock (Details) $ / shares in Units, $ in Millions	Oct. 15, 2018	Jul. 31, 2015$ / sharesshares	Sep. 29, 2018USD ($)day$ / shares	Sep. 30, 2017USD ($)	Jun. 30, 2018USD ($)
Redeemable Noncontrolling Interest [Line Items]
Redemption value			$ 35.8		$ 35.8
Dividends paid for preferred stock			$ 0.4	$ 0.2
Subsequent Event
Redeemable Noncontrolling Interest [Line Items]
Redemption notice period	30 days
Redeemable Convertible Series A Preferred Stock
Redeemable Noncontrolling Interest [Line Items]
Number of years before stock is redeemable at the holders' option			5 years
Redemption value			$ 35.8
Conversion price per share (usd per share) | $ / shares		$ 24.63
Conversion price equal to the volume weighted average price per share (as a percent)		125.00%
Number of regular-way trading days used to set conversion price | day			5
Liquidation preference per share (usd per share) | $ / shares			$ 1,000
Annual dividend rate			2.50%
Accrued dividends			$ 0.2		$ 0.4
Redeemable Convertible Series A Preferred Stock | Viavi
Redeemable Noncontrolling Interest [Line Items]
Number of shares sold (in shares) | shares		40,000
Redemption notice period		30 days
Redeemable Convertible Series A Preferred Stock | Amada | Viavi
Redeemable Noncontrolling Interest [Line Items]
Number of shares sold (in shares) | shares		35,805
Number of shares canceled (in shares) | shares		4,195

Convertible Senior Notes - Narr

Convertible Senior Notes - Narrative (Details) - Convertible Debt - Convertible Senior Notes Due 2024	1 Months Ended	3 Months Ended
	Mar. 31, 2017USD ($)d$ / shares	Sep. 29, 2018USD ($)	Jun. 30, 2018USD ($)	Sep. 30, 2017	Mar. 08, 2017USD ($)
Debt Instrument [Line Items]
Debt, stated interest rate	0.25%	0.25%
Conversion rate	0.0164965
Conversion price (usd per share) | $ / shares	$ 60.62
Conversion price premium percentage	132.50%
Conversion threshold trading days | d	20
Conversion threshold consecutive trading days | d	30
Conversion threshold percentage of stock price trigger	130.00%
Sale price of common stock (usd per share) | $ / shares	$ 78.80
Conversion threshold measurement period	5 days
Conversion threshold percentage of conversion rate from measurement period	98.00%
Percentage of principal amount required to be paid upon contingent note repurchase		100.00%
Derivative liability fair value					$ 129,900,000
Residual principal amount of notes before issuance costs	$ 320,100,000
Debt issuance costs	$ 7,700,000
Effective interest rate on the liability component	5.40%	5.40%		5.40%
Debt, remaining discount amortization period		65 months
Debt, aggregate principal amount	$ 450,000,000	$ 450,000,000	$ 450,000,000

Convertible Senior Notes - Comp

Convertible Senior Notes - Components of 2024 Notes (Details) - USD ($)	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2017
Liability component:
Net carrying amount of the liability component	$ 456,200,000
Convertible Debt | Convertible Senior Notes Due 2024
Liability component:
Principal	450,000,000	$ 450,000,000	$ 450,000,000
Unamortized debt discount	(111,500,000)	(115,800,000)
Net carrying amount of the liability component	$ 338,500,000	$ 334,200,000

Convertible Senior Notes - Inte

Convertible Senior Notes - Interest Expense Related to 2024 Notes (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Mar. 31, 2017
Debt Instrument [Line Items]
Amortization of the debt discount	$ 4.3	$ 4.1
Convertible Debt | Convertible Senior Notes Due 2024
Debt Instrument [Line Items]
Contractual interest expense	0.3	0.3
Amortization of the debt discount	4.3	4.1
Total interest expense	$ 4.6	$ 4.4
Effective interest rate on the liability component	5.40%	5.40%	5.40%

Derivative Liability - Narrativ

Derivative Liability - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Derivative [Line Items]
Unrealized gain (loss) on derivative liability	$ (2.1)	$ 4.2
Level 3 | Embedded Derivative Liability | Series A Preferred Stock
Derivative [Line Items]
Unrealized gain (loss) on derivative liability	$ (2.1)	$ 4.2

Derivative Liability - Reconcil

Derivative Liability - Reconciliation of Fair Value of Embedded Derivative (Details) - Embedded Derivative Liability - Series A Preferred Stock - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance as of beginning of period	$ 52.4	$ 51.6
Unrealized (gain) loss on the Series A Preferred Stock derivative liability	2.1	(4.2)
Balance as of end of period	$ 54.5	$ 47.4

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Schedule of Changes in Goodwill (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Changes in goodwill
Balance at the beginning of the period	$ 11.3	$ 11.4
Foreign currency translation adjustment	0	0.1
Balance at the end of the period	11.3	11.5
Optical Communications
Changes in goodwill
Balance at the beginning of the period	5.9	5.9
Foreign currency translation adjustment	0	0.2
Balance at the end of the period	5.9	6.1
Commercial Lasers
Changes in goodwill
Balance at the beginning of the period	5.4	5.5
Foreign currency translation adjustment	0	(0.1)
Balance at the end of the period	$ 5.4	$ 5.4

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	3 Months Ended
	Sep. 29, 2018	Jun. 30, 2018	Sep. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill impairment		$ 0
Amortization related to acquired developed technologies	$ 800,000		$ 800,000

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Acquired Developed Technology and Other Intangibles (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 112.6	$ 112.5
Accumulated Amortization	(106.3)	(105.5)
Net	6.3	7
Acquired developed technologies
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	105.6	105.5
Accumulated Amortization	(99.3)	(98.5)
Net	6.3	7
Other intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7	7
Accumulated Amortization	(7)	(7)
Net	$ 0	$ 0

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Details of Amortization Expense (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 0.8	$ 0.8
Cost of sales
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 0.8	$ 0.8

Goodwill and Other Intangible_7

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Fiscal Years
Remainder of 2019	$ 2.2
2,020	2.9
2,021	0.5
2,022	0.5
Thereafter	0.2
Net	$ 6.3	$ 7

Restructuring and Related Cha_3

Restructuring and Related Charges - Summary of Activity of Restructuring and Related Charges (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Summary of Restructuring Activity and Related Charges
Balance as of beginning of period	$ 1.9	$ 3.8
Charges	1.3	2.9
Payments	(1.6)	(5.4)
Balance as of end of period	$ 1.6	$ 1.3

Restructuring and Related Cha_4

Restructuring and Related Charges - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Restructuring and Related Charges
Restructuring and related charges	$ 1.3	$ 2.9
Severance costs
Restructuring and Related Charges
Restructuring and related charges		(0.1)
Other Charges
Restructuring and Related Charges
Restructuring and related charges		$ 3

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Dec. 30, 2017	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Provision for (benefit from) income taxes	$ 5.2		$ (3.6)
Released valuation allowance due to recognized tax benefit
Unrecognized tax benefits liability	$ 9

Stock-Based Compensation and _3

Stock-Based Compensation and Stock Plans - Narrative (Details) - USD ($)	Nov. 04, 2016	Jun. 23, 2015	Sep. 29, 2018	Sep. 30, 2017	Jun. 30, 2018	Jul. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock authorized for issuance under plan (in shares)		8,500,000
Common stock reserved for future issuance (in shares)						2,100,000
Increase in number of shares that may be issued	3,000,000
Shares of common stock available for grant (in shares)			5,000,000		5,600,000
Stock-based compensation			$ 10,800,000	$ 9,300,000
Stock-based compensation capitalized to inventory			$ 2,100,000		$ 2,600,000
Options exercised (in shares)			40,270
Intrinsic value of options exercised			$ 700,000
Stock-based compensation cost related to awards granted to employees			$ 97,800,000
Estimated amortization period			2 years 1 month
Shares issued to employees (in shares)			0	0
Full Value Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Stock options issued and outstanding (in shares)			2,000,000
Full Value Awards | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			1 year
Full Value Awards | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			4 years
Options
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Shares of common stock available for grant (in shares)			5,000,000
Options | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			3 years
Stock awards expiration period			5 years
Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			4 years
Stock awards expiration period			10 years
RSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			3 years
RSUs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			1 year
RSUs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			4 years
RSAs | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			1 year
RSAs | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Vesting period			4 years
PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock authorized for issuance under plan (in shares)			200,000
Vesting period			3 years
Stock-based compensation			$ 0
2015 Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Common stock authorized for issuance under plan (in shares)		3,000,000
Shares of common stock available for grant (in shares)			2,300,000
Stock-based compensation			$ 1,000,000	$ 800,000
Discount rate provided under purchase plan (as a percent)		15.00%
Look-back period		6 months

Stock-Based Compensation and _4

Stock-Based Compensation and Stock Plans - Stock-Based Compensation (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 10.8	$ 9.3
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	3.3	2.7
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	2.8	3.1
Selling, general and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Stock-based compensation	$ 4.7	$ 3.5

Stock-Based Compensation and _5

Stock-Based Compensation and Stock Plans - Stock Option and Stock Award Activity (Details) - $ / shares shares in Millions	3 Months Ended	12 Months Ended
	Sep. 29, 2018	Jun. 30, 2018
Restricted Stock Units
Number of Shares
Unvested balance as of beginning of period (in shares)	1.7
Granted (in shares)	0.7
Vested (in shares)	(0.5)
Canceled (in shares)	(0.1)
Unvested balance as of end of period (in shares)	1.8	1.7
Weighted-Average Grant Date Fair Value per Share
Unvested balance as of beginning of period (usd per share)	$ 43.1
Granted (usd per share)	67.8
Vested (usd per share)	38.4
Canceled (usd per share)	49.6
Unvested balance as of end of period (usd per share)	$ 55.2	$ 43.1
Granted awards (in shares)	0.7
Restricted Stock Awards
Number of Shares
Unvested balance as of beginning of period (in shares)	0.1
Granted (in shares)	0
Vested (in shares)	0
Canceled (in shares)	0
Unvested balance as of end of period (in shares)	0.1	0.1
Weighted-Average Grant Date Fair Value per Share
Unvested balance as of beginning of period (usd per share)	$ 32.5
Granted (usd per share)	0
Vested (usd per share)	0
Canceled (usd per share)	0
Unvested balance as of end of period (usd per share)	$ 32.5	$ 32.5
Granted awards (in shares)	0
Performance Stock Units
Number of Shares
Unvested balance as of beginning of period (in shares)	0.2
Granted (in shares)	0	0.1
Vested (in shares)	(0.1)
Canceled (in shares)	0
Unvested balance as of end of period (in shares)	0.1	0.2
Weighted-Average Grant Date Fair Value per Share
Unvested balance as of beginning of period (usd per share)	$ 52
Granted (usd per share)	0
Vested (usd per share)	52
Canceled (usd per share)	0
Unvested balance as of end of period (usd per share)	$ 0	$ 52
Granted awards (in shares)	0	0.1
Awards granted as percent of target goal		100.00%
Performance Stock Units | Minimum
Weighted-Average Grant Date Fair Value per Share
Percent that may be earned of original grant		0.00%
Performance Stock Units | Maximum
Weighted-Average Grant Date Fair Value per Share
Percent that may be earned of original grant		200.00%

Stock-Based Compensation and _6

Stock-Based Compensation and Stock Plans - Awards Available for Grant (Details) shares in Millions	3 Months Ended
	Sep. 29, 2018shares
Awards Available for Grant
Balance as of beginning of period (in shares)	5.6
Granted (in shares)	(0.7)
Canceled (in shares)	0.1
Balance as of end of period (in shares)	5

Stock-Based Compensation and _7

Stock-Based Compensation and Stock Plans - Schedule of Assumptions Used to Estimate Fair Value (Details) - 2015 Purchase Plan	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Expected term (years)	6 months	6 months
Expected volatility	58.80%	53.00%
Risk-free interest rate	2.02%	1.02%
Dividend yield	0.00%	0.00%

Commitments and Contingencies -

Commitments and Contingencies - Schedule of Future Minimum Annual Lease Payments Under Non-Cancellable Operating Leases (Details) $ in Millions	Sep. 29, 2018USD ($)
Fiscal Years
Remainder of 2019	$ 8.8
2,020	6.5
2,021	5.1
2,022	3.4
2,023	2.4
Thereafter	1.8
Total minimum operating lease payments	$ 28

Commitments and Contingencies_2

Commitments and Contingencies - Operating and Capital Lease Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Rental expense relating to building and equipment	$ 2.8	$ 3.4
Capital Leased Assets [Line Items]
Equipment acquired under capital lease agreement	662.3		$ 636.2
Capital lease assets
Capital Leased Assets [Line Items]
Equipment acquired under capital lease agreement	$ 15.6

Commitments and Contingencies_3

Commitments and Contingencies - Schedule of Future Minimum Annual Lease Payments Under Capital Lease (Details) $ in Millions	Sep. 29, 2018USD ($)
Fiscal Years
Remainder of 2019	$ 6.7
2,020	0.4
Total minimum capital lease payments	7.1
Less: amount representing interest	(0.1)
Present value of capital lease obligation	$ 7

Commitments and Contingencies_4

Commitments and Contingencies - Acquisition Contingencies Narrative (Details) - Private Company Acquisition - USD ($) $ in Millions	1 Months Ended	3 Months Ended
	Feb. 28, 2017	Sep. 29, 2018
Business Acquisition [Line Items]
Contingent liabilities incurred	$ 3.6
Liabilities incurred	$ 3
Transferred contingent liability achievement period	12 months
Amount of purchase price retained as security	$ 1
Amount paid in full		$ 1

Commitments and Contingencies_5

Commitments and Contingencies - Convertible Senior Notes Due 2014 (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018	Mar. 31, 2017
Fiscal Years
Remainder of 2019	$ 0.6
2,020	1.1
2,021	1.1
2,022	1.1
2,023	1.1
Thereafter	451.2
Net carrying amount of the liability component	$ 456.2
2024 Notes | Convertible Debt
Debt Instrument [Line Items]
Debt, stated interest rate	0.25%		0.25%
Fiscal Years
Net carrying amount of the liability component	$ 338.5	$ 334.2

Commitments and Contingencies_6

Commitments and Contingencies - Purchase Obligations Narrative (Details) $ in Millions	3 Months Ended
	Sep. 29, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Legally-binding purchase commitment obligations	$ 206.5
Typical duration of supply agreements with single or limited source vendors	1 year

Commitments and Contingencies_7

Commitments and Contingencies - Product Warranties Narrative (Details)	3 Months Ended
	Sep. 29, 2018
Loss Contingencies [Line Items]
Product warranty term	12 months
Minimum
Loss Contingencies [Line Items]
Product warranty term	6 months
Maximum
Loss Contingencies [Line Items]
Product warranty term	5 years

Commitments and Contingencies_8

Commitments and Contingencies - Schedule of Changes in Warranty Reserve (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Changes in warranty reserve
Balance as of beginning of period	$ 6.6	$ 9.7
Provision for warranty	1.2	1
Utilization of reserve	(1.2)	(1.3)
Balance as of end of period	$ 6.6	$ 9.4

Operating Segments and Geogra_3

Operating Segments and Geographic Information - Narrative (Details)	3 Months Ended
	Sep. 29, 2018regionsegment
Segment Reporting [Abstract]
Number of reportable segments | segment	2
Number of geographic regions | region	3

Operating Segments and Geogra_4

Operating Segments and Geographic Information - Schedule of Information on Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Information on reportable segments
Net revenue	$ 354.1	$ 243.2
Gross profit	126	68.5
Stock-based compensation	(10.8)	(9.3)
Amortization of intangibles	(0.8)	(0.8)
Gross profit	126	68.5
Operating segments
Information on reportable segments
Net revenue	354.1	243.2
Gross profit	142.6	82.7
Gross profit	142.6	82.7
Operating segments | OpComms
Information on reportable segments
Net revenue	310.1	207.9
Gross profit	124.9	72.1
Gross profit	124.9	72.1
Operating segments | Lasers
Information on reportable segments
Net revenue	44	35.3
Gross profit	17.7	10.6
Gross profit	17.7	10.6
Unallocated corporate items
Information on reportable segments
Stock-based compensation	(3.3)	(2.7)
Amortization of intangibles	(0.8)	(0.8)
Other charges	(12.5)	(10.7)
Inventory write-downs		7
Unallocated corporate items | Thailand
Information on reportable segments
Other charges	$ (12.7)	$ (3.1)

Operating Segments and Geogra_5

Operating Segments and Geographic Information - Schedule of Percentage of Total Net Revenue Attributable to Reportable Segments (Details) - Product offerings - Revenue number in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
OpComms
Concentration Risk [Line Items]
Concentration risk percentage	31010.00%	20790.00%
OpComms | Telecom
Concentration Risk [Line Items]
Concentration risk percentage	14290.00%	11040.00%
OpComms | Datacom
Concentration Risk [Line Items]
Concentration risk percentage	3420.00%	4520.00%
OpComms | Consumer and Industrial
Concentration Risk [Line Items]
Concentration risk percentage	13300.00%	5230.00%
Lasers
Concentration Risk [Line Items]
Concentration risk percentage	4400.00%	3530.00%

Operating Segments and Geogra_6

Operating Segments and Geographic Information - Schedule of Revenue by Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 354.1	$ 243.2
Americas
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 79.1	$ 60.6
Americas | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	22.40%	25.00%
United States
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 21.9	$ 33.6
United States | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	6.20%	13.80%
Mexico
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 56.3	$ 24.8
Mexico | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	15.90%	10.30%
Other Americas
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 0.9	$ 2.2
Other Americas | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	0.30%	0.90%
Asia Pacific
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 245.7	$ 157.2
Asia Pacific | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	69.40%	64.60%
Hong Kong
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 65.5	$ 48.9
Hong Kong | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	18.50%	20.10%
Japan
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 36.1	$ 34.1
Japan | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	10.20%	14.00%
South Korea
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 70	$ 10.9
South Korea | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	19.80%	4.50%
Other Asia-Pacific
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 74.1	$ 63.3
Other Asia-Pacific | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	20.90%	26.00%
EMEA
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 29.3	$ 25.4
EMEA | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	8.20%	10.40%

Operating Segments and Geogra_7

Operating Segments and Geographic Information - Schedule of Net Revenue Generated From a Single Customer (Details) - Customer concentration risk - Revenue	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Customer A
Concentration Risk [Line Items]
Concentration risk percentage	30.50%	16.30%
Customer B
Concentration Risk [Line Items]
Concentration risk percentage	15.00%
Customer C
Concentration Risk [Line Items]
Concentration risk percentage	13.00%	14.20%
Customer D
Concentration Risk [Line Items]
Concentration risk percentage		10.40%

Operating Segments and Geogra_8

Operating Segments and Geographic Information - Schedule of Long-lived Assets by Geographic Region (Details) - USD ($) $ in Millions	Sep. 29, 2018	Jun. 30, 2018
Property, Plant and Equipment, net
Total long-lived assets	$ 318.6	$ 306.9
United States
Property, Plant and Equipment, net
Total long-lived assets	103.6	97.6
China
Property, Plant and Equipment, net
Total long-lived assets	62.1	70
Thailand
Property, Plant and Equipment, net
Total long-lived assets	131.3	107.4
Other countries
Property, Plant and Equipment, net
Total long-lived assets	$ 21.6	$ 31.9

Operating Segments and Geogra_9

Operating Segments and Geographic Information - Concentration Risk for Inventory Purchases (Details) - Supplier concentration risk - Cost of goods, inventory	3 Months Ended
	Sep. 29, 2018	Sep. 30, 2017
Vendor A
Concentration Risk [Line Items]
Concentration risk percentage	51.50%	44.90%
Vendor B
Concentration Risk [Line Items]
Concentration risk percentage	25.10%	25.70%
Vendor C
Concentration Risk [Line Items]
Concentration risk percentage		10.90%