Lumentum (LITE) 10-Q 5 May 20 2020 Q3 Quarterly report Financial data

COVER PAGE

COVER PAGE - shares shares in Millions	9 Months Ended
	Mar. 28, 2020	Apr. 27, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 28, 2020
Document Transition Report	false
Entity File Number	001-36861
Entity Registrant Name	Lumentum Holdings Inc.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-3108385
Entity Address, Address Line One	1001 Ridder Park Drive
Entity Address, City or Town	San Jose
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95131
City Area Code	408
Local Phone Number	546-5483
Title of 12(b) Security	Common Stock, par value of $0.001 per share
Trading Symbol	LITE
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		74.9
Entity Central Index Key	0001633978
Amendment Flag	false
Current Fiscal Year End Date	--06-27
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Income Statement [Abstract]
Net revenue	$ 402.8	$ 432.9	$ 1,310.5	$ 1,160.7
Cost of sales	231.2	316.5	757.2	788.3
Amortization of acquired developed intangibles	13.9	28.1	38.8	33.3
Gross profit	157.7	88.3	514.5	339.1
Operating expenses:
Research and development	48.7	57.7	149.6	135.1
Selling, general and administrative	61.3	55.2	180.4	150.9
Restructuring and related charges	2.7	21.1	4.9	30.2
Impairment charges	2.5	30.7	2.5	30.7
Total operating expenses	115.2	164.7	337.4	346.9
Income (loss) from operations	42.5	(76.4)	177.1	(7.8)
Unrealized gain on derivative liability	0	0	0	8.8
Interest expense	(15.6)	(11.3)	(45.3)	(24.9)
Other income (expense), net	21.7	5.2	27.9	11.7
Income (loss) before income taxes	48.6	(82.5)	159.7	(12.2)
Provision for (benefit from) income taxes	5.2	(8.2)	19.6	(1.6)
Net income (loss)	43.4	(74.3)	140.1	(10.6)
Items reconciling net income to net income attributable to common stockholders:
Less: Cumulative dividends on Series A Preferred Stock	0	0	0	(0.3)
Less: Earnings allocated to Series A Preferred Stock	0	0	0	(1.2)
Net income (loss) attributable to common stockholders - Basic	43.4	(74.3)	140.1	(12.1)
Net income (loss) attributable to common stockholders - Diluted	$ 43.4	$ (74.3)	$ 140.1	$ (12.1)
Net income (loss) per share attributable to common stockholders:
Basic (In dollars per share)	$ 0.58	$ (0.98)	$ 1.84	$ (0.18)
Diluted (in dollars per share)	$ 0.56	$ (0.98)	$ 1.80	$ (0.18)
Shares used to compute net income (loss) per share attributable to common stockholders:
Basic (in shares)	74.8	76.2	76.2	68.7
Diluted (in shares)	77.5	76.2	77.7	68.7

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 43.4	$ (74.3)	$ 140.1	$ (10.6)
Other comprehensive income (loss), net of tax:
Net change in cumulative translation adjustment	0	0	0	(0.6)
Net change in unrealized gain (loss) on available-for-sale securities	(1.2)	1.3	(1.3)	1.8
Net change in defined benefit obligations	0	0	0	(0.1)
Other comprehensive income (loss), net of tax	(1.2)	1.3	(1.3)	1.1
Comprehensive income (loss), net of tax	$ 42.2	$ (73)	$ 138.8	$ (9.5)

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Current assets:
Cash and cash equivalents	$ 688.3	$ 432.6
Short-term investments	763.1	335.9
Accounts receivable, net	261.8	238
Inventories	172.7	228.8
Prepayments and other current assets	77.1	97.5
Total current assets	1,963	1,332.8
Property, plant and equipment, net	410.1	433.3
Operating lease right-of-use assets, net	81.7
Goodwill	368.9	368.9
Other intangible assets, net	338	395.4
Deferred income taxes	102.7	169.6
Other non-current assets	4.3	16.6
Total assets	3,268.7	2,716.6
Current liabilities:
Accounts payable	144.6	160.8
Accrued payroll and related expenses	50.9	42.3
Accrued expenses	32.9	46.7
Term loan, current	0	5
Operating lease liabilities, current	11.5
Other current liabilities	46.8	39.2
Total current liabilities	286.7	294
Convertible notes	1,106	351.9
Term loan, non-current	0	484
Operating lease liabilities, non-current	59.1
Deferred tax liability	49	55.9
Other non-current liabilities	33.7	33.7
Total liabilities	1,534.5	1,219.5
Commitments and contingencies (Note 17)
Stockholders’ equity:
Common stock, $0.001 par value, 990,000,000 authorized shares, 74,874,176 and 76,653,478 shares issued and outstanding as of March 28, 2020 and June 29, 2019, respectively	0.1	0.1
Additional paid-in capital	1,659.1	1,360.8
Retained earnings	69.2	129.1
Accumulated other comprehensive income	5.8	7.1
Total stockholders’ equity	1,734.2	1,497.1
Total liabilities and stockholders’ equity	$ 3,268.7	$ 2,716.6

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Mar. 28, 2020	Jun. 29, 2019
Statement of Financial Position [Abstract]
Common stock, par value (usd per share)	$ 0.001	$ 0.001
Common stock, authorized shares (in shares)	990,000,000	990,000,000
Common stock, shares issued (in shares)	74,874,176	76,653,478
Common stock, shares outstanding (in shares)	74,874,176	76,653,478

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non-Controlling Interest Redeemable Convertible Series A Preferred Stock
Balance (in shares) at Jun. 30, 2018						0
Balance at Jun. 30, 2018						$ 35.8
Balance (in shares) at Sep. 29, 2018						0
Balance at Sep. 29, 2018						$ 35.8
Balance at the beginning of period (in shares) at Jun. 30, 2018		62.8
Balance at the beginning of the period at Jun. 30, 2018	$ 926.1	$ 0.1	$ 753.2	$ 166.4	$ 6.4
Increase (Decrease) in Stockholders' Equity
Net income (loss)	47.4			47.4
Other comprehensive income (loss)	0.5				0.5
Declared dividend for preferred stock	(0.2)			(0.2)
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		0.5
Issuance of shares pursuant to equity plans, net of tax withholdings	0		0
Stock-based compensation	10.3		10.3
Balance at the end of period (in shares) at Sep. 29, 2018		63.3
Balance at the end of the period at Sep. 29, 2018	983.5	$ 0.1	763.5	213	6.9
Balance (in shares) at Jun. 30, 2018						0
Balance at Jun. 30, 2018						$ 35.8
Balance (in shares) at Mar. 30, 2019						0
Balance at Mar. 30, 2019						$ 0
Balance at the beginning of period (in shares) at Jun. 30, 2018		62.8
Balance at the beginning of the period at Jun. 30, 2018	926.1	$ 0.1	753.2	166.4	6.4
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(10.6)
Other comprehensive income (loss)	1.1
Balance at the end of period (in shares) at Mar. 30, 2019		76.3
Balance at the end of the period at Mar. 30, 2019		$ 0.1	1,341.4	154.9	7.5
Balance (in shares) at Jun. 30, 2018						0
Balance at Jun. 30, 2018						$ 35.8
Balance at the beginning of period (in shares) at Jun. 30, 2018		62.8
Balance at the beginning of the period at Jun. 30, 2018	926.1	$ 0.1	753.2	166.4	6.4
Increase (Decrease) in Stockholders' Equity
Conversion of preferred stock to common stock			79.4
Balance at the end of period (in shares) at Jun. 29, 2019		76.7
Balance at the end of the period at Jun. 29, 2019	1,497.1	$ 0.1	1,360.8	129.1	7.1
Balance (in shares) at Sep. 29, 2018						0
Balance at Sep. 29, 2018						$ 35.8
Increase (Decrease) in Non-Controlling Interest Redeemable Convertible Series A Preferred Stock
Conversion of preferred stock to common stock						$ (35.8)
Balance (in shares) at Dec. 29, 2018						0
Balance at Dec. 29, 2018						$ 0
Balance at the beginning of period (in shares) at Sep. 29, 2018		63.3
Balance at the beginning of the period at Sep. 29, 2018	983.5	$ 0.1	763.5	213	6.9
Increase (Decrease) in Stockholders' Equity
Net income (loss)	16.3			16.3
Other comprehensive income (loss)	(0.7)				(0.7)
Declared dividend for preferred stock	(0.1)			(0.1)
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		0.2
Issuance of shares pursuant to equity plans, net of tax withholdings	(0.8)		(0.8)
Issuance of shares pursuant to merger agreement, net of tax withholdings (in shares)		11
Issuance of shares pursuant to merger agreement, net of tax withholdings	460.1		460.1
ESPP shares issued (in shares)		0.1
ESPP shares issued	4.7		4.7
Stock-based compensation	17.3		17.3
Conversion of preferred stock to common stock (in shares)		1.5
Conversion of preferred stock to common stock	79.4		79.4
Balance at the end of period (in shares) at Dec. 29, 2018		76.1
Balance at the end of the period at Dec. 29, 2018	1,559.7	$ 0.1	1,324.2	229.2	6.2
Balance (in shares) at Mar. 30, 2019						0
Balance at Mar. 30, 2019						$ 0
Increase (Decrease) in Stockholders' Equity
Net income (loss)	(74.3)			(74.3)
Other comprehensive income (loss)	1.3				1.3
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		0.2
Issuance of shares pursuant to equity plans, net of tax withholdings	0.1		0.1
Stock-based compensation	17.1		17.1
Balance at the end of period (in shares) at Mar. 30, 2019		76.3
Balance at the end of the period at Mar. 30, 2019		$ 0.1	1,341.4	154.9	7.5
Balance at the beginning of period (in shares) at Jun. 29, 2019		76.7
Balance at the beginning of the period at Jun. 29, 2019	1,497.1	$ 0.1	1,360.8	129.1	7.1
Increase (Decrease) in Stockholders' Equity
Net income (loss)	47.6			47.6
Other comprehensive income (loss)	0.1				0.1
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		0.5
Issuance of shares pursuant to equity plans, net of tax withholdings	0
Stock-based compensation	16.5		16.5
Balance at the end of period (in shares) at Sep. 28, 2019		77.2
Balance at the end of the period at Sep. 28, 2019	1,561.3	$ 0.1	1,377.3	176.7	7.2
Balance at the beginning of period (in shares) at Jun. 29, 2019		76.7
Balance at the beginning of the period at Jun. 29, 2019	1,497.1	$ 0.1	1,360.8	129.1	7.1
Increase (Decrease) in Stockholders' Equity
Net income (loss)	140.1
Other comprehensive income (loss)	(1.3)
Conversion of preferred stock to common stock			79.4
Balance at the end of period (in shares) at Mar. 28, 2020		74.9
Balance at the end of the period at Mar. 28, 2020	1,734.2	$ 0.1	1,659.1	69.2	5.8
Balance at the beginning of period (in shares) at Sep. 28, 2019		77.2
Balance at the beginning of the period at Sep. 28, 2019	1,561.3	$ 0.1	1,377.3	176.7	7.2
Increase (Decrease) in Stockholders' Equity
Net income (loss)	49.1			49.1
Other comprehensive income (loss)	(0.2)				(0.2)
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		0.3
Issuance of shares pursuant to equity plans, net of tax withholdings	0
Exercise of stock options	0.3		0.3
Equity component of the 2026 Notes, net of tax of $67.0 million and issuance costs of $2.3 million	245.9		245.9
ESPP shares issued (in shares)		0.1
ESPP shares issued	4.9		4.9
Repurchases of common stock (in shares)		(2.9)
Repurchases of common stock	(200)			(200)
Stock-based compensation	20.3		20.3
Balance at the end of period (in shares) at Dec. 28, 2019		74.7
Balance at the end of the period at Dec. 28, 2019	1,681.6	$ 0.1	1,648.7	25.8	7
Increase (Decrease) in Stockholders' Equity
Net income (loss)	43.4			43.4
Other comprehensive income (loss)	(1.2)				(1.2)
Issuance of shares pursuant to equity plans, net of tax withholdings (in shares)		0.2
Issuance of shares pursuant to equity plans, net of tax withholdings	(8.6)		(8.6)
Exercise of stock options	0.2		0.2
Stock-based compensation	18.8		18.8
Balance at the end of period (in shares) at Mar. 28, 2020		74.9
Balance at the end of the period at Mar. 28, 2020	$ 1,734.2	$ 0.1	$ 1,659.1	$ 69.2	$ 5.8

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERRED STOCK AND STOCKHOLDERS' EQUITY (Parenthetical) - 2026 Notes - Convertible Debt $ in Millions	Dec. 28, 2019USD ($)
Equity component	$ 67
Debt issuance costs	$ 2.3

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended				9 Months Ended		12 Months Ended
	Mar. 28, 2020	Sep. 28, 2019	Mar. 30, 2019	Sep. 29, 2018	Mar. 28, 2020	Mar. 30, 2019	Jun. 29, 2019	Mar. 28, 2020	Jun. 29, 2019	Mar. 30, 2019
OPERATING ACTIVITIES:
Net income (loss)	$ 43.4	$ 47.6	$ (74.3)	$ 47.4	$ 140.1	$ (10.6)
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation expense	27.5		29		87.8	74.7
Stock-based compensation					56.1	46.5
Loss on early extinguishment of debt					8	0
Unrealized gain on derivative liability	0		0		0	(8.8)
Gain on sale of product lines					(13.8)	0
Amortization of acquired intangibles	20		31.7		57.4	37.7
Loss and impairment charges on property, plant and equipment					8.9	30.7
Amortization of debt discount and debt issuance costs					25.3	13.6
Amortization of inventory fair value adjustment in connection with Oclaro acquisition					5.8	15.8
Other non-cash income					(2.7)	(0.2)
Changes in operating assets and liabilities:
Accounts receivable					(23.8)	(37.2)
Inventories					48.3	14
Operating lease right-of-use assets, net					9.6
Prepayments and other current and non-currents assets					16.5	(10.6)
Income taxes, net					13	(5.1)
Accounts payable					(15.3)	15.7
Accrued payroll and related expenses					8.6	(1.4)
Operating lease liabilities					(10.4)
Accrued expenses and other current and non-current liabilities					(17.8)	27.6
Net cash provided by operating activities					401.6	202.4
INVESTING ACTIVITIES:
Payments for acquisition of property, plant and equipment					(64.9)	(80.5)
Payment for asset acquisition					(4)	(1.3)
Payment for Oclaro acquisition, net of cash acquired					0	(619.8)
Proceeds from sale of product lines					18.9	0
Purchases of short-term investments					(692.8)	(196.1)
Proceeds from maturities and sales of short-term investments					264.9	172.4
Net cash used in investing activities					(477.9)	(725.3)
FINANCING ACTIVITIES:
Repurchase of common stock					(200)	0
Proceeds from the issuance of 0.50% Convertible Notes due 2026, net of issuance costs					1,042.4	0
Tax payments related to restricted stock					(8.6)	(2.4)
Payment of dividends - Series A Preferred Stock					0	(0.7)
Payment of acquisition related holdback					0	(1)
Proceeds from employee stock plans					4.9	4.7
Proceeds from term loan, net of issuance costs					0	490.8
Principal payments on finance leases					(9.2)	(6.1)
Proceeds from the exercise of stock options					0.5	0.1
Repayment of term loan					(497.5)	(1.3)
Net cash provided by financing activities					332.5	484.1
Effect of exchange rates on cash and cash equivalents					0	(0.2)
Increase (decrease) in cash, cash equivalents, and restricted cash					256.2	(39)
Cash and cash equivalents at beginning of period		432.6		397.3	432.6	397.3	$ 397.3
Cash, cash equivalents, and restricted cash at end of period	688.8		358.3		688.8	358.3	432.6
Reconciliation of cash, cash equivalents, and restricted cash, reported within the condensed consolidated balance sheets to the total amounts reported on the condensed consolidated statements of cash flows:
Cash and cash equivalents								$ 688.3	$ 432.6	$ 358.3
Restricted cash								0.5		0
Total cash, cash equivalents, and restricted cash at end of period	$ 688.8	$ 432.6	$ 358.3	$ 397.3	688.8	358.3	$ 397.3	$ 688.8	$ 432.6	$ 358.3
Supplemental disclosure of cash flow information:
Cash paid for taxes					6.6	3.3
Cash paid for interest					10.7	8.7
Supplemental disclosure of non-cash transactions:
Unpaid property, plant and equipment in accounts payable and accrued expenses					11.7	26
Issuance costs in current liabilities					0.2	0
Right-of-use assets obtained in exchange for new operating lease liabilities					2.2
Issuance of common stock upon conversion of Series A Preferred Stock					0	79.4
Net transfer of assets from property plant and equipment to assets held-for-sale					0	31.4
Issuance of common stock and replacement awards in connection with Oclaro acquisition					$ 0	$ 460.1

CONDENSED CONSOLIDATED STATEM_6

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical)	Mar. 28, 2020	Dec. 12, 2019
2026 Notes | Convertible Debt
Debt Instrument [Line Items]
Debt, stated interest rate	0.50%	0.50%

Description of Business and Sum

Description of Business and Summary of Significant Accounting Policies	9 Months Ended
	Mar. 28, 2020
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 Optical Communications (“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 Original Equipment Manufacturers (“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, gaming, and other applications who then integrate our devices within their products, for eventual resale to consumers and also into other industrial applications. Further, we have begun shipping prototype units of diode lasers and optical subassemblies containing diode lasers and other optical devices to automotive customers for sensing and LiDAR 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, business combinations and goodwill. On December 10, 2018, we completed our merger with Oclaro, Inc. (“Oclaro”), a provider of optical components and modules for the long-haul, metro and data center markets. Our condensed consolidated financial statements include the operating results of Oclaro beginning from the date of acquisition. Refer to “ Note 4. Business Combinations ” for further discussion of the merger. The COVID-19 pandemic has created and may continue to create significant uncertainty in global financial markets, which has disrupted and harmed, and may continue to disrupt and harm, the Company's business, financial condition, and results of operations. The extent of the impact of COVID-19 on the Company's operational and financial performance will depend on certain developments, including but not limited to the duration and spread of the outbreak, duration of local, state and federal issued public health orders in each jurisdiction where we operate or in which our customers and suppliers operate, impact on our customers and our sales cycles, impact on our supply chain and manufacturing partners, impact on our employees and impact on regional and worldwide economies and financial markets in general, all of which are uncertain and cannot be predicted. Fiscal Years We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th. Every fifth or sixth fiscal year will have a 53-week period. The additional week in a 53-week year is added to the third quarter, making such quarter consist of 14 weeks. Our fiscal 2021 will be a 53-week year. Our fiscal 2020 is a 52-week year ending on June 27, 2020 , with the quarter ended March 28, 2020 being a 13-week quarterly period. Our fiscal 2019 was a 52-week year that ended on June 29, 2019 , with the quarter ended March 30, 2019 being a 13-week quarterly period. 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 period presentation, including the reclassification of capital lease obligations that existed as of June 29, 2019 to finance lease liabilities within other current liabilities and other non-current liabilities in our condensed consolidated balance sheets, as a result of the adoption of the new accounting guidance for leases. Refer to “ Note 2. Recently Issued Accounting Pronouncements ” for details. The reclassification of the prior period amounts did not impact previously reported condensed consolidated financial statements. Accounting Policies The accompanying 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 29, 2019 . Except for the accounting policies for lease accounting as a result of the adoption of Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842) , there have been no significant changes to our significant accounting policies as of and for the three months ended March 28, 2020 , as compared to the significant accounting policies described in our Annual Report on Form 10-K for the year ended June 29, 2019 . Adoption of Leases (Topic 842) On June 30, 2019, the first day of fiscal year 2020, we adopted Topic 842, using the modified retrospective transition approach. Refer to “ Note 2. Recently Issued Accounting Pronouncements ” regarding the impact of adoption. We determine if an arrangement is a lease at inception for arrangements with an initial term of more than 12 months, and classify it as either finance or operating. Finance leases are generally those that allow us to substantially utilize or pay for the entire asset over its estimated useful life. Finance leases are recorded in property, plant and equipment, net, and finance lease liabilities within other current and other non-current liabilities on our condensed consolidated balance sheets. We have lease arrangements with lease and non-lease components, and the non-lease components for our finance leases are accounted for separately, based on estimated stand-alone values, and are not included in the initial measurement of our finance lease assets and corresponding liabilities. Finance lease assets are amortized in operating expenses on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease term, with the interest component included in interest expense and recognized using the effective interest method over the lease term. Operating leases are recorded in operating lease right-of-use assets, net, and operating lease liabilities, current and non-current on our condensed consolidated balance sheets. For operating leases of buildings, we account for non-lease components, such as common area maintenance, as a component of the lease, and include it in the initial measurement of our operating lease assets and corresponding liabilities. Operating lease assets are amortized on a straight-line basis in operating expenses over the lease term. Our lease liabilities are recognized based on the present value of the remaining fixed lease payments, over the lease term, using a discount rate of similarly secured borrowings available to us. For the purpose of lease liability measurement, we consider only payments that are fixed and determinable at the time of commencement. Any variable payments that depend on an index or rate are expensed as incurred. Our lease terms may include options to extend when it is reasonably certain that we will exercise that option. Our lease assets also include any lease payments made and exclude any lease incentives received prior to commencement. Our lease assets are tested for impairment in the same manner as long-lived assets used in operations. We generally recognize sublease income on a straight-line basis over the sublease term.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	9 Months Ended
	Mar. 28, 2020
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Note 2. Recently Issued Accounting Pronouncements Accounting Pronouncements Recently Adopted Effective June 30, 2019, we adopted Topic 842, using the modified retrospective transition approach. We applied the new guidance to all leases existing as of the date of adoption. Our reported results beginning with the first quarter of fiscal 2020 reflect the application of Topic 842, while prior period amounts have not been adjusted and continue to be reported in accordance with our historical accounting under Topic 840. We elected the practical expedient package permitted under the transition approach. As such, we did not reassess whether any expired or existing contracts are or contain leases, we did not reassess our historical lease classification, and we did not reassess our initial direct costs for any leases that existed prior to June 30, 2019. We have also elected to combine lease and non-lease components at a portfolio level for our operating leases of buildings and not to report leases with an initial term of 12 months or less on our balance sheet. As of the date of adoption, we recognized operating lease assets of $91.5 million , with corresponding operating lease liabilities of $81.5 million on the condensed consolidated balance sheets. The difference between the operating lease right-of-use assets and operating lease liabilities primarily represents the existing asset recognized in relation to the favorable terms of an operating lease acquired through a business combination offset by our deferred rent and ASC 420 “cease-use” balances. All existing leases that were classified as capital leases under Topic 840 are classified as finance leases under the new guidance. As of adoption, we recognized finance lease assets of $12.4 million in property, plant and equipment, net, with corresponding finance lease liabilities of $12.4 million on the condensed consolidated balance sheets. For further information regarding the impact of Topic 842 adoption, see “ Note 1. Description of Business and Summary of Significant Accounting Policies ” and “ Note 9. Leases ”. 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 U.S. Tax Cuts and Jobs Act of 2017 (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. We adopted ASU 2018-02 in the first quarter of fiscal 2020 with no impact to our condensed 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 early adopted ASU 2017-04 in our first quarter of fiscal 2020. The implementation of ASU 2017-04 did not have an impact on our condensed consolidated financial statements. Accounting Pronouncements Not Yet Effective In December 2019, FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (Topic 740), which is intended to simplify various aspects related to accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and which also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for us at the beginning of fiscal 2022, including interim periods within that reporting period, although early adoption is permitted. We are currently evaluating the impact of ASU 2019-12 on our condensed 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 post-retirement benefit plans. The new guidance is effective for fiscal years ending after December 15, 2020, with early adoption 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 condensed 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, with early adoption permitted. ASU 2018-13 requires that certain of the amendments be applied prospectively, while other amendments should be applied retrospectively to all periods presented. ASU 2018-13 is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of ASU 2018-13 on our condensed consolidated financial statements and related disclosures. 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. This standard requires capitalization of the implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. Further, the standard also requires the Company to expense the capitalized implementation costs of a hosting arrangement over the term of the hosting arrangement. This standard is effective for us in our first quarter of fiscal 2021. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on our consolidated financial statements. In June 2016, FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments and a subsequent amendment, ASU 2018-19 (collectively, Topic 326). Topic 326 requires measurement and recognition of expected credit losses for financial assets held. Topic 326 is effective for annual periods beginning after December 15, 2019, including interim periods within those periods, with early adoption permitted. ASU 2016-13 is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of our pending adoption of Topic 326 on our condensed consolidated financial statements.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Mar. 28, 2020
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 Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Basic Earnings per Common Share Net income (loss) $ 43.4 $ (74.3 ) $ 140.1 $ (10.6 ) Less: Cumulative dividends on Series A Preferred Stock — — — (0.3 ) Less: Earnings allocated to Series A Preferred Stock — — — (1.2 ) Net income (loss) attributable to common stockholders - Basic $ 43.4 $ (74.3 ) $ 140.1 $ (12.1 ) Weighted average common shares outstanding including Series A Preferred Stock 74.8 76.2 76.2 69.4 Less: Weighted average Series A Preferred Stock — — — (0.7 ) Basic weighted average common shares outstanding 74.8 76.2 76.2 68.7 Net income (loss) per share attributable to common stockholders - Basic $ 0.58 $ (0.98 ) $ 1.84 $ (0.18 ) Diluted Earnings per Common Share Net income (loss) attributable to common stockholders - Basic $ 43.4 $ (74.3 ) $ 140.1 $ (12.1 ) Net income (loss) attributable to common stockholders - Diluted $ 43.4 $ (74.3 ) $ 140.1 $ (12.1 ) Weighted average common shares outstanding for basic earnings per common share 74.8 76.2 76.2 68.7 Effect of dilutive securities from 2015 Equity Incentive Plan 1.0 — 0.8 — Shares issuable assuming conversion of the 2024 Notes 1.7 — 0.7 — Diluted weighted average common shares outstanding 77.5 76.2 77.7 68.7 Net income (loss) per share attributable to common stockholders - Diluted $ 0.56 $ (0.98 ) $ 1.80 $ (0.18 ) Our Series A Preferred Stock was considered a participating security, meaning that it had the right to participate in undistributed earnings with our common stock. On November 2, 2018, the remaining 35,805 shares of our Series A Preferred Stock were converted into 1.5 million shares of our common stock. Refer to “ Note 11. Non-Controlling Interest Redeemable Convertible Preferred Stock and Derivative Liability ” for further discussion. Prior to conversion, the holders of our Series A Preferred Stock were entitled to share in dividends, on an as-converted basis, if the holders of our common stock were to receive dividends. Through the date of conversion, we used the two-class method to compute earnings per share. 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. Diluted earnings per common share is calculated similar 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 is computed using the more dilutive of the treasury stock method or the if-converted method. Potentially dilutive common shares result from the assumed exercise of outstanding stock options, assumed vesting of outstanding equity awards, assumed issuance of stock under the employee stock purchase plan, and assumed conversion of our outstanding $450 million in aggregate principal amount of 0.25% Convertible Notes due in 2024 (the “2024 Notes”) and $1,050 million in aggregate principal amount of 0.50% Convertible Notes due in 2026 (the “2026 Notes” and together with the 2024 Notes, the “convertible notes”), all using the treasury stock method. We have the ability and intent to settle the face value of our convertible notes in cash. Therefore, we use the treasury stock method for calculating the dilutive impact of the convertible notes. The 2026 Notes will have no impact on diluted earnings per share until the average price of our common stock exceeds the conversion price of $99.29 . The potentially dilutive shares resulting from the 2024 Notes were included in the calculation of diluted income per share for the three and nine months ended March 28, 2020 since the average price of our common stock exceeded the conversion price of $60.62 . Refer to “ Note 12. Debt ” for further discussion. Anti-dilutive potential shares from the 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. Anti-dilutive shares excluded from the calculation of diluted earnings per share were not material for the three and nine months ended March 28, 2020 , respectively. Anti-dilutive shares excluded from the calculation of diluted earnings per share were 0.7 million shares and 0.6 million shares, respectively, for the three and nine months ended March 30, 2019 , respectively.

Business Combinations

Business Combinations	9 Months Ended
	Mar. 28, 2020
Business Combinations [Abstract]
Business Combinations	Note 4. Business Combinations On December 10, 2018, we acquired all of the outstanding common stock of Oclaro, a provider of optical components and modules for the long-haul, metro and data center markets. Oclaro’s products provide differentiated solutions for optical networks and high-speed interconnects driving the next wave of streaming video, cloud computing, application virtualization and other bandwidth-intensive and high-speed applications. The total fair value of consideration given in connection with the acquisition of Oclaro consisted of the following: Shares Per Share Total Consideration (in millions) Cash paid for outstanding Oclaro common stock $ 964.8 Lumentum common shares issued to Oclaro stockholders 10,941,436 $ 41.80 457.4 Replacement equity awards for Oclaro equity awards 2.7 Total consideration $ 1,424.9 The total transaction consideration was funded by the issuance of Lumentum common stock, new debt, and cash balances of the combined company. Our allocation of the purchase price of Oclaro based on the estimated fair values of the assets acquired and liabilities assumed is as follows ( in millions ): As Previously Reported on June 29, 2019 Cash and cash equivalents $ 345.0 Accounts receivable, net 68.0 Inventories 155.0 Prepayments and other current assets 33.7 Property, plant and equipment, net 134.7 Intangibles 444.0 Deferred income tax asset 42.6 Other non-current assets 16.6 Accounts payable (57.8 ) Accrued payroll and related expenses (11.4 ) Accrued expenses (8.3 ) Other current liabilities (6.1 ) Deferred tax liability (75.8 ) Other non-current liabilities (12.9 ) Goodwill 357.6 Total purchase price $ 1,424.9 The amounts presented in the table above pertained to the preliminary purchase price allocation reported in our Form 10-K for the year ended June 29, 2019, filed with the Securities and Exchange Commission on August 27, 2019. There have been no measurement period adjustments during the three and nine months ended March 28, 2020 . On April 18, 2019, we completed the sale of our Datacom transceiver module business based in Sagamihara, Japan and the transfer of related employees to Cambridge Industries Group (“CIG”) for $25.5 million in net cash. These product lines were initially acquired by us through the acquisition of Oclaro. This business did not meet the criteria for assets held-for-sale under the relevant accounting guidance as of December 10, 2018, the date of our acquisition of Oclaro, in our purchase price allocation. The assets and liabilities transferred to CIG were $33.5 million and $7.0 million , respectively. Supplemental Pro Forma Information The supplemental pro forma financial information presented below is for illustrative purposes only and is not necessarily indicative of the financial position or results of operations that would have been realized if the acquisition had been completed on the date indicated, does not reflect synergies that might have been achieved, nor is it indicative of future operating results or financial position. The pro forma adjustments are based upon currently available information and certain assumptions we believe are reasonable under the circumstances. The following supplemental pro forma information presents the combined results of operations for the nine months ended March 30, 2019, as if Oclaro had been acquired as of the beginning of fiscal year 2018. The supplemental pro forma information includes adjustments to amortization and depreciation for acquired intangible assets and property and equipment, adjustments to share-based compensation expense, the fair value adjustments on the inventories acquired, transaction costs, interest expense and amortization of the term loan debt issuance costs. The unaudited supplemental pro forma financial information for the period presented is as follows ( in millions ): Nine Months Ended March 30, 2019 Net revenue $ 1,374.8 Net loss (18.2 )

Assets and Liabilities Held For

Assets and Liabilities Held For Sale	9 Months Ended
	Mar. 28, 2020
Discontinued Operations and Disposal Groups [Abstract]
Assets and Liabilities Held For Sale	Note 5. Assets and Liabilities Held For Sale We continually evaluate our existing portfolio of businesses to maximize long-term shareholder value. We consider assets and liabilities as held-for-sale when management approves and commits to a plan to actively market assets or a group of assets for sale. Assets held-for-sale are recorded initially at the lower of its carrying value or its estimated fair value, less estimated costs to sell. Upon designation as an asset held-for-sale, we discontinue recording depreciation expense on such asset. Lithium Niobate modulators Following our acquisition of Oclaro, we announced our plan to discontinue development and manufacturing of Lithium Niobate modulators and wind down these operations in our San Donato, Italy site. In the second quarter of fiscal year 2020, we entered into an agreement with Advanced Fiber Resources (Zhuhai) Ltd. ("AFR"), a leading provider of passive optical components, to sell the assets associated with certain Lithium Niobate product lines manufactured by our San Donato site for $17 million . This sale was completed in the third quarter of fiscal year 2020, and we received the final proceeds of $16.9 million , net of $0.1 million retainer from AFR. The assets sold of $6.6 million primarily consisted of property, plant and equipment, net, inventory, and operating lease right-of-use assets, net, offset by liabilities transferred of $3.5 million primarily attributable to operating lease liabilities. During the three months ended March 28, 2020, we recognized a gain of $13.8 million , which was recorded in our other income (expense), net in the condensed consolidated statements of operations. With the close of this transaction, our telecom transmission product strategy is now focused on Indium Phosphide photonic integrated circuits, as well as components and modules that incorporate these Indium Phosphide photonic integrated circuits. Datacom transceiver modules As of June 29, 2019, we had $4.9 million of long-lived assets related to our plan to discontinue the development of future Datacom transceiver modules. As these assets were not deemed to be useful, we retired them from active use and classified them as held-for-sale on our balance sheet. This is a result of the strategic change we made in the third quarter of fiscal year 2019 when we announced the exit from the Datacom transceiver modules and investments in the new Datacom chips development. In the third quarter of fiscal year 2020, we sold $2.0 million and impaired $1.6 million of these assets held-for-sale. As of March 28, 2020, the remaining balance of $1.3 million

Cash, Cash Equivalents and Shor

Cash, Cash Equivalents and Short-term Investments	9 Months Ended
	Mar. 28, 2020
Cash and Cash Equivalents [Abstract]
Cash, Cash Equivalents and Short-term Investments	Note 6. 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 March 28, 2020: Cash $ 121.3 $ — $ — $ 121.3 Cash equivalents: Commercial paper 72.6 — — 72.6 Corporate debt securities 3.0 — — 3.0 Money market funds 426.2 — — 426.2 U.S. Treasury securities 65.1 0.1 — 65.2 Total cash and cash equivalents $ 688.2 $ 0.1 $ — $ 688.3 Short-term investments: Certificates of deposit $ 4.4 $ — $ — $ 4.4 Commercial paper 88.1 — — 88.1 Corporate debt securities 343.2 0.2 (2.5 ) 340.9 Foreign government bonds 4.0 — — 4.0 U.S. Agency securities 23.0 0.1 — 23.1 U.S. Treasury securities 300.7 1.9 — 302.6 Total short-term investments $ 763.4 $ 2.2 $ (2.5 ) $ 763.1 June 29, 2019: Cash $ 213.8 $ — $ — $ 213.8 Cash equivalents: Commercial paper 37.4 — — 37.4 Money market funds 168.1 — — 168.1 U.S. Treasury securities 13.3 — — 13.3 Total cash and cash equivalents $ 432.6 $ — $ — $ 432.6 Short-term investments: Certificates of deposit $ 1.9 $ — $ — $ 1.9 Commercial paper 22.3 — — 22.3 Asset-backed securities 54.9 0.2 — 55.1 Corporate debt securities 207.6 0.9 (0.1 ) 208.4 Municipal bonds 1.3 — — 1.3 Mortgage-backed securities 6.6 — — 6.6 Foreign government bonds 6.2 — — 6.2 U.S. Agency securities 4.6 — — 4.6 U.S. Treasury securities 29.4 0.1 — 29.5 Total short-term investments $ 334.8 $ 1.2 $ (0.1 ) $ 335.9 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 and nine months ended March 28, 2020 and March 30, 2019 , 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 and nine months ended March 28, 2020 , our other income (expense), net was $21.7 million and $27.9 million , respectively, and includes interest income on cash equivalents and short-term investments of $5.2 million and $12.6 million , respectively. During the three and nine months ended March 30, 2019 , our other income (expense), net was $5.2 million and $11.7 million , respectively, and includes interest income on cash equivalents and short-term investments of $3.9 million and $10.0 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 March 28, 2020: U.S. Agency securities $ 8.0 $ — $ — $ — $ 8.0 $ — Certificates of deposit 2.5 — — — 2.5 — Commercial paper 55.2 — — — 55.2 — Corporate debt securities 301.1 (2.5 ) — — 301.1 (2.5 ) Total $ 366.8 $ (2.5 ) $ — $ — $ 366.8 $ (2.5 ) June 29, 2019: Asset-backed securities $ 4.2 $ — $ 5.9 $ — $ 10.1 $ — Corporate debt securities 9.6 — 35.9 (0.1 ) 45.5 (0.1 ) Foreign government bonds — — 2.1 — 2.1 — U.S. government bonds 6.9 — — — 6.9 — Total $ 20.7 $ — $ 43.9 $ (0.1 ) $ 64.6 $ (0.1 ) The following table classifies our short-term investments by contractual maturities ( in millions ): March 28, 2020 June 29, 2019 Amortized Cost Fair Value Amortized Cost Fair Value Due in 1 year $ 720.1 $ 720.0 $ 178.9 $ 179.1 Due in 1 year through 5 years 43.3 43.1 148.1 149.0 Due in 5 years through 10 years — — 6.0 6.0 Due after 10 years — — 1.8 1.8 $ 763.4 $ 763.1 $ 334.8 $ 335.9 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	9 Months Ended
	Mar. 28, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Note 7. 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 our 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 our 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. Our procedures include controls to ensure that appropriate fair values are recorded, including comparing the fair values obtained from our pricing service against fair values obtained from another independent source. Based on quoted market prices as of March 28, 2020 , the fair values of the 2026 Notes and the 2024 Notes (refer to “ Note 12. Debt ”) were approximately $1.0 billion and $581.0 million , respectively, determined using Level 2 inputs as they are not actively traded in 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 March 28, 2020: (1) Assets: Cash equivalents: Commercial paper $ — $ 72.6 $ — $ 72.6 Corporate debt securities — 3.0 — 3.0 Money market funds 426.2 — — 426.2 U.S. Treasury securities 65.2 — — 65.2 Short-term investments: Certificates of deposit — 4.4 — 4.4 Commercial paper — 88.1 — 88.1 Corporate debt securities — 340.9 — 340.9 Foreign government bonds — 4.0 — 4.0 U.S. Agency securities — 23.1 — 23.1 U.S. Treasury securities 302.6 — — 302.6 Total assets $ 794.0 $ 536.1 $ — $ 1,330.1 (1) Excludes $121.3 million in cash held in our bank accounts at March 28, 2020 . Level 1 Level 2 Level 3 Total June 29, 2019: (1) Assets: Cash equivalents: Commercial paper $ — $ 37.4 $ — $ 37.4 Money market funds 168.1 — — 168.1 U.S. Treasury securities 13.3 — — 13.3 Short-term investments: Certificates of deposit — 1.9 — 1.9 Commercial paper — 22.3 — 22.3 Asset-backed securities — 55.1 — 55.1 Corporate debt securities — 208.4 — 208.4 Municipal bonds — 1.3 — 1.3 Mortgage-backed securities — 6.6 — 6.6 Foreign government bonds — 6.2 — 6.2 U.S. Agency securities — 4.6 — 4.6 U.S. Treasury securities 29.5 — — 29.5 Total assets $ 210.9 $ 343.8 $ — $ 554.7 Other accrued liabilities: Acquisition contingency $ — $ — $ 2.7 $ 2.7 Total other accrued liabilities $ — $ — $ 2.7 $ 2.7 (1) Excludes $213.8 million in cash held in our bank accounts as of June 29, 2019 . 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 2019, we concluded that our intangible and other long-lived assets were not impaired. No impairment charges were recorded during the three and nine months ended March 28, 2020 and March 30, 2019 . Refer to “ Note 10. Goodwill and Other Intangible Assets ”.

Balance Sheet Details

Balance Sheet Details	9 Months Ended
	Mar. 28, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Balance Sheet Details	Note 8. Balance Sheet Details Accounts receivable allowances As of March 28, 2020 and June 29, 2019 , our accounts receivable allowance balance was $1.7 million and $4.5 million , respectively. Inventories The components of inventories were as follows ( in millions ): March 28, 2020 June 29, 2019 Raw materials and purchased parts $ 55.4 $ 78.3 Work in process 67.9 72.5 Finished goods 49.4 78.0 Inventories (1) $ 172.7 $ 228.8 (1) The inventory balance as of June 29, 2019 includes $5.7 million , net of amortization, related to the inventory step-up adjustment from the Oclaro acquisition. As of March 28, 2020 , the inventory step-up adjustment from the Oclaro acquisition was fully amortized. Prepayments and other current assets The components of prepayments and other current assets were as follows ( in millions ): March 28, 2020 June 29, 2019 Prepayments $ 29.7 $ 32.4 Vendor receivable 29.8 36.3 Value added tax receivable 11.5 11.9 Advances to contract manufacturers — 8.7 Assets held-for-sale 1.3 4.9 Other current assets 4.8 3.3 Prepayments and other current assets $ 77.1 $ 97.5 Operating lease right-of-use assets, net Operating lease right-of-use assets, net were as follows ( in millions ): March 28, 2020 Operating lease right-of-use assets $ 90.3 Less: accumulated amortization (8.6 ) Operating lease right-of-use assets, net $ 81.7 Property , plant and equipment, net The components of property, plant and equipment, net were as follows ( in millions ): March 28, 2020 June 29, 2019 Land $ 44.2 $ 44.2 Buildings and improvement 112.9 103.7 Machinery and equipment (1) 514.1 500.5 Computer equipment and software 25.6 25.4 Furniture and fixtures 6.6 4.9 Leasehold improvements 28.1 31.2 Finance lease right-of-use assets (1) 28.1 16.0 Construction in progress 53.0 46.8 812.6 772.7 Less: Accumulated depreciation (1) (402.5 ) (339.4 ) Property, plant and equipment, net $ 410.1 $ 433.3 (1) Included in the table above is our equipment acquired under finance leases. As of March 28, 2020 and June 29, 2019, the accumulated depreciation of finance lease right-of-use assets was $24.2 million and $11.2 million , respectively. For fiscal 2019 in accordance with Topic 842, we have reclassified $16.0 million of equipment acquired under finance leases from machinery and equipment to finance lease right-of-use assets to conform to current period presentation. During the three and nine months ended March 28, 2020 , we recorded depreciation expense of $27.5 million and $87.8 million , respectively. During the three and nine months ended March 30, 2019 , we recorded depreciation expense of $29.0 million and $74.7 million , respectively. Included in these amounts were depreciation expense for equipment acquired under finance leases in the amount of $4.8 million and $13.0 million for the three and nine months ended March 28, 2020 , respectively, and $1.5 million and $4.6 million for the three and nine months ended March 30, 2019 , respectively. In fiscal 2019, we purchased a property in San Jose, California for $54.6 million in cash. We relocated our corporate headquarters to this new San Jose location in the second quarter of fiscal 2020. The allocations of value were $21.7 million to buildings and improvement and $32.9 million to the land. Our construction in progress primarily includes machinery and equipment that we expect to place in service in the next 12 months. Other current liabilities The components of other current liabilities were as follows (in millions) : March 28, 2020 June 29, 2019 Restructuring accrual and related charges (1) $ 2.6 $ 14.6 Warranty accrual (2) 5.4 7.5 Deferred revenue and customer deposits 1.7 2.9 Finance lease liabilities, current (3) 3.9 0.4 Income tax payable 30.4 8.7 Other current liabilities 2.8 5.1 Other current liabilities $ 46.8 $ 39.2 (1) Refer to “ Note 14. Restructuring and Related Charges .” (2) Refer to “ Note 17. Commitments and Contingencies .” (3) For fiscal 2019 in accordance with Topic 842, we have reclassified amounts from capital lease obligations to finance lease liabilities to conform to current period presentation. In addition to the $3.9 million of finance lease liabilities recorded within other current liabilities as of March 28, 2020 , we also recorded $0.1 million within other non-current liabilities in the condensed consolidated balance sheet. Refer to “ Note 9. Leases .” Other non-current liabilities The components of other non-current liabilities were as follows ( in millions ): March 28, 2020 June 29, 2019 Asset retirement obligations $ 4.9 $ 4.5 Pension and related accrual (1) 10.0 7.9 Deferred rent — 2.2 Unrecognized tax benefit 18.1 18.7 Finance lease liabilities, non-current 0.1 — Other non-current liabilities 0.6 0.4 Other non-current liabilities $ 33.7 $ 33.7 (1) We have defined benefit pension plans in Japan, Switzerland, and Thailand. As of March 28, 2020, the projected benefit obligations in Japan, Switzerland, and Thailand were $2.8 million , $4.7 million , and $2.5 million , respectively. As of June 29, 2019 , the projected benefit obligations for Japan and Switzerland were $2.8 million and $5.0 million , respectively. Pension and related accruals as of June 29, 2019 also include $0.1 million attributable to post-retirement benefits for executives.

Leases

Leases	9 Months Ended
	Mar. 28, 2020
Leases [Abstract]
Leases	Note 9. Leases We lease certain real and personal property from unrelated third parties under non-cancellable operating leases that expire at various dates through fiscal 2033. These operating leases are mainly for administrative offices, research-and-development and manufacturing facilities, as well as sales offices in various countries around the world. Certain leases require us to pay property taxes, insurance and routine maintenance, and include escalation clauses. Many leases include one or more options to renew. We do not assume renewals in our determination of the lease term unless the renewals are deemed to be reasonably assured at lease commencement. We have also entered into various finance leases to obtain servers and certain other equipment for our operations. These arrangements are typically for two to four years. As of March 28, 2020 , we sublease certain floors of our offices in the United Kingdom, the United States, Canada, and Japan. These subleases will expire at various dates by fiscal year 2023. We anticipate receiving approximately $5.9 million in sublease income over the next three years . The components of lease costs, lease term, and discount rate are as follows: Three Months Ended Nine Months Ended March 28, 2020 March 28, 2020 Finance lease cost ( in millions ): Amortization of right-of-use assets $ 4.8 $ 13.0 Interest — 0.1 Operating lease cost 3.9 11.9 Variable lease cost 0.4 1.5 Short-term lease cost 0.7 1.7 Sublease income (0.7 ) (1.9 ) Total lease cost $ 9.1 $ 26.3 Weighted average remaining lease term ( in years ): Operating leases 8.9 Finance leases 0.7 Weighted average discount rate: Operating leases 3.65 % Finance leases 4.38 % As of March 28, 2020 , maturities of our operating and finance lease liabilities, which do not include short-term leases and variable lease payments, were as follows ( in millions ): Fiscal Years Operating Leases (1) Finance Leases Total Remainder of 2020 $ 3.3 $ 3.4 $ 6.7 2021 13.1 0.6 13.7 2022 12.3 — 12.3 2023 11.1 — 11.1 2024 9.4 — 9.4 Thereafter 31.4 — 31.4 Total minimum lease payments $ 80.6 $ 4.0 $ 84.6 Less: amount representing interest (10.0 ) — (10.0 ) Present value of total lease liabilities $ 70.6 $ 4.0 $ 74.6 (1) Non-cancellable sublease proceeds for the remainder of fiscal 2020, and fiscal 2021, 2022, and 2023 of $0.7 million , $2.4 million , $2.2 million , and $0.6 million , respectively, are not included in the table above. Prior to our adoption of Topic 842, future minimum lease payments as of June 29, 2019, which were undiscounted, were net of our sublease income amounts, and included lease and non-lease components, were as follows ( in millions ): Fiscal Years Operating Leases Finance Leases Total 2020 $ 13.9 $ 0.8 $ 14.7 2021 12.1 — 12.1 2022 11.2 — 11.2 2023 11.3 — 11.3 2024 9.8 — 9.8 Thereafter 31.7 — 31.7 Total minimum operating lease payments $ 90.0 $ 0.8 $ 90.8
Leases	Note 9. Leases We lease certain real and personal property from unrelated third parties under non-cancellable operating leases that expire at various dates through fiscal 2033. These operating leases are mainly for administrative offices, research-and-development and manufacturing facilities, as well as sales offices in various countries around the world. Certain leases require us to pay property taxes, insurance and routine maintenance, and include escalation clauses. Many leases include one or more options to renew. We do not assume renewals in our determination of the lease term unless the renewals are deemed to be reasonably assured at lease commencement. We have also entered into various finance leases to obtain servers and certain other equipment for our operations. These arrangements are typically for two to four years. As of March 28, 2020 , we sublease certain floors of our offices in the United Kingdom, the United States, Canada, and Japan. These subleases will expire at various dates by fiscal year 2023. We anticipate receiving approximately $5.9 million in sublease income over the next three years . The components of lease costs, lease term, and discount rate are as follows: Three Months Ended Nine Months Ended March 28, 2020 March 28, 2020 Finance lease cost ( in millions ): Amortization of right-of-use assets $ 4.8 $ 13.0 Interest — 0.1 Operating lease cost 3.9 11.9 Variable lease cost 0.4 1.5 Short-term lease cost 0.7 1.7 Sublease income (0.7 ) (1.9 ) Total lease cost $ 9.1 $ 26.3 Weighted average remaining lease term ( in years ): Operating leases 8.9 Finance leases 0.7 Weighted average discount rate: Operating leases 3.65 % Finance leases 4.38 % As of March 28, 2020 , maturities of our operating and finance lease liabilities, which do not include short-term leases and variable lease payments, were as follows ( in millions ): Fiscal Years Operating Leases (1) Finance Leases Total Remainder of 2020 $ 3.3 $ 3.4 $ 6.7 2021 13.1 0.6 13.7 2022 12.3 — 12.3 2023 11.1 — 11.1 2024 9.4 — 9.4 Thereafter 31.4 — 31.4 Total minimum lease payments $ 80.6 $ 4.0 $ 84.6 Less: amount representing interest (10.0 ) — (10.0 ) Present value of total lease liabilities $ 70.6 $ 4.0 $ 74.6 (1) Non-cancellable sublease proceeds for the remainder of fiscal 2020, and fiscal 2021, 2022, and 2023 of $0.7 million , $2.4 million , $2.2 million , and $0.6 million , respectively, are not included in the table above. Prior to our adoption of Topic 842, future minimum lease payments as of June 29, 2019, which were undiscounted, were net of our sublease income amounts, and included lease and non-lease components, were as follows ( in millions ): Fiscal Years Operating Leases Finance Leases Total 2020 $ 13.9 $ 0.8 $ 14.7 2021 12.1 — 12.1 2022 11.2 — 11.2 2023 11.3 — 11.3 2024 9.8 — 9.8 Thereafter 31.7 — 31.7 Total minimum operating lease payments $ 90.0 $ 0.8 $ 90.8

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	9 Months Ended
	Mar. 28, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Note 10. Goodwill and Other Intangible Assets Goodwill On December 10, 2018, we completed the acquisition of Oclaro. We recognized goodwill in the amount of $357.6 million for the acquisition of Oclaro and allocated it to our OpComms segment. There have been no measurement periods or other adjustments to goodwill during the three and nine months ended March 28, 2020 . The following table presents our goodwill balance by the reportable segments as of March 28, 2020 ( in millions) : Optical Communications Commercial Lasers Total Balance as of March 28, 2020 $ 363.5 $ 5.4 $ 368.9 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 2019 , we completed the annual impairment test of goodwill, which indicated there was no goodwill impairment. We considered the impacts of COVID-19 pandemic on our business and determined that there were no indicators of goodwill impairment as of March 28, 2020 . Other Intangibles In connection with our acquisition of Oclaro in fiscal year 2019, we recorded $443.0 million as the fair value of the acquired developed technologies and other intangible assets. This amount excludes $1.0 million of in-process research and development assets that were subsequently sold to CIG. Refer to “ Note 4. Business Combinations ”. The intangible assets are amortized on a straight-line basis over the estimated useful lives, except for customer relationships and order backlog, which are amortized using an accelerated method of amortization over the expected customer lives, which more accurately reflects the pattern of realization of economic benefits expected to be obtained. Acquired developed technologies and order backlog are amortized to cost of sales and customer relationships is amortized to selling, general and administrative. IPR&D is initially capitalized at fair value as an intangible asset with an indefinite life and assessed for impairment thereafter. When an IPR&D project is completed, the IPR&D is reclassified as an amortizable purchased intangible asset and amortized over the asset’s estimated useful life expected to range between 4 to 9 years . The following tables present details of our other intangibles, including those acquired in connection with the Oclaro acquisition, as of the periods presented ( in millions, except for weighted average remaining amortization period ): March 28, 2020 Gross Carrying Amounts Accumulated Amortization Net Carrying Amounts Weighted average remaining amortization period (years) Acquired developed technologies (1) $ 346.5 $ (161.9 ) $ 184.6 3.5 Customer relationships 149.3 (30.9 ) 118.4 6.7 In-process research and development (1) 35.0 — 35.0 n/a Order backlog 22.0 (22.0 ) — — Other intangibles 2.7 (2.7 ) — — Total intangible assets $ 555.5 $ (217.5 ) $ 338.0 (1) During the three and nine months ended March 28, 2020 , we completed $7 million and $59 million of IPR&D projects, respectively, and reclassified the value assigned to them to acquired developed technologies. The amount will be amortized over the assets’ estimated useful life of 4 to 5 years. June 29, 2019 Gross Carrying Amounts Accumulated Amortization Net Carrying Amounts Weighted average remaining amortization period (years) Acquired developed technologies $ 287.5 $ (125.2 ) $ 162.3 3.8 Customer relationships 149.3 (12.3 ) 137.0 7.5 In-process research and development 94.0 — 94.0 n/a Order backlog 22.0 (19.9 ) 2.1 0.5 Other intangibles 2.7 (2.7 ) — — Total intangible assets $ 555.5 $ (160.1 ) $ 395.4 The following table presents details of amortization for the periods presented (in millions ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Cost of sales $ 13.9 $ 28.1 $ 38.8 $ 33.3 Selling, general and administrative 6.1 3.6 18.6 4.4 Total amortization of intangibles $ 20.0 $ 31.7 $ 57.4 $ 37.7 Based on the carrying amount of our acquired developed technologies and other intangibles, excluding IPR&D, as of March 28, 2020 , and assuming no future impairment of the underlying assets, the estimated future amortization is as follows (in millions): Fiscal Years Remainder of 2020 $ 20.3 2021 78.9 2022 76.4 2023 52.9 2024 33.1 Thereafter 41.4 Total future amortization $ 303.0

Non-Controlling Interest Redeem

Non-Controlling Interest Redeemable Convertible Preferred Stock and Derivative Liability	9 Months Ended
	Mar. 28, 2020
Temporary Equity Disclosure [Abstract]
Non-Controlling Interest Redeemable Convertible Preferred Stock and Derivative Liability	Note 11. Non-Controlling Interest Redeemable Convertible Preferred Stock and Derivative Liability 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 us, 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. As of June 30, 2018, the Series A Preferred Stock was referred to as our Non-Controlling Interest Redeemable Convertible Preferred Stock within these condensed consolidated financial statements, and was recorded at $35.8 million . On October 15, 2018, we issued a 30 -day notice of intent to the holders of Series A Preferred Stock to convert all shares of Series A Preferred Stock at a conversion price equal to the Issuance Value divided by $24.63 plus the accrued and unpaid dividends on each share and any past due dividends, whether or not authorized or declared. On November 2, 2018, we received notice from Amada of their intent to convert the Series A Preferred Stock and we issued 1.5 million shares of our common stock to Amada upon the conversion of the 35,805 shares of Series A Preferred Stock and recorded $79.4 million in additional paid in capital in the condensed consolidated balance sheet. Through the date of conversion, the Series A Preferred Stock conversion feature was bifurcated from the Series A Preferred Stock and accounted for separately as a derivative liability. The derivative liability was measured at fair value each reporting period, and at the date of conversion, with the change in fair value recorded in the condensed consolidated statements of operations. Through the date of conversion, 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, were 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 were payable on March 31, June 30, September 30 and December 31 of each year commencing on September 30, 2015. The accrued dividends as of November 2, 2018, the effective date of the conversion of all outstanding Series A Preferred Stock, was $0.3 million . During the three months ended March 30, 2019 , we paid $0.4 million in dividends to the holders of Series A Preferred Stock. In connection with the conversion of the Series A Preferred Stock on November 2, 2018, we recorded $79.4 million in additional paid in capital which is reflected within the condensed consolidated balance sheets as of March 28, 2020 and June 29, 2019 . For the nine months ended March 30, 2019 , we recorded $8.8 million unrealized gain to our condensed consolidated statements of operations.

Debt

Debt	9 Months Ended
	Mar. 28, 2020
Debt Disclosure [Abstract]
Debt	Note 12. Debt Convertible Notes 2026 Notes In December 2019, we issued $1,050.0 million in aggregate principal amount of the 2026 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 2026 Notes are governed by an indenture between the Company and U.S. Bank National Association (the “2026 Indenture”). We used approximately $196 million of the net proceeds of the offering to repay in full all amounts outstanding under our term loan credit facility, and a portion of the net proceeds of the offering to purchase approximately $200 million of our common stock concurrently with the pricing of the offering in privately negotiated transactions. The 2026 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 2026 Notes wil l bear interest at a rate of 0.50% per year, payable semi-annually in arrears on June 15 and December 15 of each year, beginning on June 15, 2020. The 2026 Notes will mature on December 15, 2026, unless earlier redeemed, repurchased by us, or converted pursuant to their terms. The initial conversion rate is 10.0711 shares of common stock per $1,000 principal amount of the 2026 Notes (which is equivalent to an initial conversion price of approximately $99.29 per share). The conversion rate is subject to adjustment upon the occurrence of certain specified events but will not be adjusted for accrued and unpaid interest. In addition, upon the occurrence of a make-whole fundamental change or our issuance of a notice of redemption, we will, in certain circumstances, increase the conversion rate by a number of additional shares for a holder that elects to convert the 2026 Notes in connection with such make-whole fundamental change or notice of redemption. Prior to the close of business on the business day immediately preceding September 15, 2026, holders of the 2026 Notes may convert their 2026 Notes only under the following circumstances: • during any fiscal quarter commencing after the fiscal quarter ended on March 28, 2020 (and only during such fiscal quarter), if the last reported sale price of the common stock for at least 20 trading days (whether or not consecutive) during a 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 conversion price of the 2026 Notes on each applicable trading day; • during the five business day period after any five consecutive trading day period (the "2026 measurement period") in which the trading price per $1,000 principal amount of the 2026 Notes for each trading day of the 2026 measurement period was less than 98% of the product of the last reported sale price of our common stock and the conversion rate for the notes on each such trading day; • if we call any or all of the 2026 Notes for redemption, at any time prior to the close of business on the second business day immediately preceding the relevant redemption date; or • upon the occurrence of specified corporate events, as specified in each indenture governing the 2026 Notes. On or after September 15, 2026 until the close of business on the second scheduled trading day immediately preceding the maturity date, holders may convert the 2026 Notes at any time. Upon conversion, we may satisfy our conversion obligation in cash, shares of common stock or a combination of cash and shares of common stock, at our election. We may redeem for cash, stock or combination of both for all or any portion of the 2026 Notes, at our option, on or after December 20, 2023, if the last reported sale price of its common stock has been at least 130% of the conversion price then in effect for at least 20 trading days (whether or not consecutive) during any 30 consecutive trading-day period (including the last trading day of such period) ending on, and including, the trading day immediately preceding the date on which we provide a notice of redemption at a redemption price equal to 100% of the principal amount of the 2026 Notes to be redeemed, plus accrued and unpaid interest to, but excluding, the redemption date. No sinking fund is provided for the 2026 Notes. Upon the occurrence of a fundamental change (as defined in the 2026 Indenture), holders may require us to repurchase all or a portion of the 2026 Notes for cash at a price equal to 100% of the principal amount of the 2026 Notes to be repurchased, plus any accrued and unpaid interest to, but excluding, the fundamental change repurchase date. In accordance with accounting for debt with conversions and other options, we bifurcated the principal amount of the 2026 Notes into liability and equity components. The liability component of the 2026 Notes was valued at $734.8 million based on the contractual cash flows discounted at an appropriate comparable market non-convertible debt borrowing rate at the date of issuance of 5.8% with the equity component representing the residual amount of the proceeds of $315.2 million , which was recorded as a debt discount. We incurred approximately $7.8 million in transaction costs in connection with the issuance of the 2026 Notes and these costs were allocated pro rata based on the relative carrying amounts of the liability and equity components. The debt discount and debt issuance costs attributable to the li ability component will be amortized to interest expense using an effective interest rate of 5.8% over the expected life of the 2026 Notes. Debt issuance costs attributable to the equity component are netted with the equity component in stockholders’ equity, and the equity component is not remeasured as long as it continues to meet the conditions for equity classification. 2024 Notes In March 2017, we issued $450.0 million of the 2024 Notes in a private placement to qualified institutional buyers pursuant to Rule 144A under 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 “2024 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, each holder of the 2024 Notes may convert their 2024 Notes only under the following circumstances: • 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; • 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 • 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 2024 Notes at any time. In addition, upon the occurrence of a make-whole fundamental change (as defined in the 2024 Indenture), 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. During the fiscal 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 2024 Notes. The debt component will accrete up to the principal amount over the expected term of the debt. Our convertible notes consisted of the following components as of the periods presented ( in millions ): Liability component: March 28, 2020 June 29, 2019 2024 Notes 2026 Notes 2024 Notes Principal $ 450.0 $ 1,050.0 $ 450.0 Unamortized debt discount and debt issuance costs (84.2 ) (309.8 ) (98.1 ) Net carrying amount of the liability component $ 365.8 $ 740.2 $ 351.9 The following table sets forth interest expense information related to the convertible notes for the periods presented (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Contractual interest expense $ 1.6 $ 0.3 $ 2.3 $ 0.9 Amortization of the debt discount and debt issuance costs 14.0 4.5 24.8 13.2 Total interest expense $ 15.6 $ 4.8 $ 27.1 $ 14.1 The future interest and principal payments related to our convertible notes are as follows as of March 28, 2020 (in millions) : Fiscal Years 2024 Notes 2026 Notes Total Remainder of 2020 $ — $ 2.7 $ 2.7 2021 1.1 5.2 6.3 2022 1.1 5.3 6.4 2023 1.1 5.2 6.3 2024 451.2 5.3 456.5 Thereafter — 1,063.1 1,063.1 Total convertible notes payments $ 454.5 $ 1,086.8 $ 1,541.3 Term Loan Facility On December 10, 2018 (the “Closing Date”), concurrent with the closing of the Oclaro merger, we entered into a Credit and Guarantee Agreement (the “Credit Agreement”), by and among us, certain of our subsidiaries, the lenders party thereto, and Deutsche Bank, as administrative agent and collateral agent for the lenders. The Credit Agreement provides for a senior secured term loan facility (the “Term Loan Facility”) in an aggregate principal amount of $500.0 million . The term loans available under the Term Loan Facility were fully drawn on the Closing Date and the proceeds of the term loans were used to consummate the merger and pay fees and expenses in connection with the merger and the Term Loan Facility. In fiscal 2019, we incurred $9.3 million of debt issuance costs in connection with the Term Loan Facility which were capitalized and recorded as a contra liability in our condensed consolidated balance sheet. These costs were amortized to interest expense using the effective interest rate method from the issuance date of December 10, 2018. In fiscal 2020, we repaid, in full, all amounts outstanding under our Term Loan Facility. During the nine months ended March 28, 2020 , we incurred an $8.0 million loss for the unamortized debt issuance costs as a result of this full repayment. The following table sets forth interest expense information related to the term loan for the periods presented (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Contractual interest expense $ — $ 6.2 $ 9.6 $ 10.2 Amortization of the debt issuance costs — 0.4 0.5 0.5 Loss on early extinguishment of debt — — 8.0 — Total interest expense $ — $ 6.6 $ 18.1 $ 10.7 For the nine months ended March 28, 2020 , we also recorded $0.1 million interest expense related to our finance leases. The following table sets forth balance sheet information related to the term loan as of the periods presented ( in millions ): March 28, 2020 June 29, 2019 Principal $ 497.5 $ 500.0 Repayment of principal (497.5 ) (2.5 ) Unamortized value of the debt issuance costs — (8.5 ) Net carrying value $ — $ 489.0 Term loan, current $ — $ 5.0 Term loan, non-current $ — $ 484.0

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Mar. 28, 2020
Equity [Abstract]
Accumulated Other Comprehensive Income (Loss)	Note 13. 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 obligations, and available-for-sale securities. The changes in accumulated other comprehensive income (loss) by component and related tax effects for each period presented were as follows ( in millions ): Foreign currency translation adjustments, net of tax (1) Defined benefit obligations, net of tax (2) Unrealized gain (loss) on available-for-sale securities, net of tax (3) Total Beginning balance as of June 29, 2019 (3) $ 9.7 $ (3.5 ) $ 0.9 $ 7.1 Other comprehensive income — — 0.1 0.1 Ending balance as of September 28, 2019 (3) 9.7 (3.5 ) 1.0 7.2 Other comprehensive loss — — (0.2 ) (0.2 ) Ending balance as of December 28, 2019 (3) 9.7 (3.5 ) 0.8 7.0 Other comprehensive loss — — (1.2 ) (1.2 ) Ending balance as of March 28, 2020 (3) $ 9.7 $ (3.5 ) $ (0.4 ) $ 5.8 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 Other comprehensive income (loss) (0.7 ) (0.1 ) 0.1 (0.7 ) Ending balance as of December 29, 2018 9.7 (2.4 ) (1.1 ) 6.2 Other comprehensive income — — 1.3 1.3 Ending balance as of March 30, 2019 $ 9.7 $ (2.4 ) $ 0.2 $ 7.5 (1) In fiscal 2019, as a result of significant changes in economic facts and circumstances, primarily due to the acquisition of Oclaro, we established the functional currency for our worldwide operations as the U.S. dollar. Translation adjustments reported prior to December 10, 2018, remain as a component of accumulated other comprehensive income in our condensed consolidated balance sheets, until all or a part of the investment in the subsidiaries is sold or liquidated. (2) We evaluate the assumptions over the fair value of our defined benefit obligations annually and make changes as necessary. (3) Fiscal 2020 balances of unrealized gain (loss) on available-for-sale securities are net of tax of $0.2 million

Restructuring and Related Charg

Restructuring and Related Charges	9 Months Ended
	Mar. 28, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Related Charges	Note 14. Restructuring and Related Charges We have initiated various strategic restructuring actions primarily intended to reduce costs, consolidate our operations, streamline the manufacturing of our products and align our business in response to market conditions and as a result of our acquisition of Oclaro on December 10, 2018. The following table summarizes the activity of restructuring and related charges during the three and nine months ended March 28, 2020 and March 30, 2019 ( in millions ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Balance as of beginning of period $ 5.0 $ 3.5 $ 14.6 $ 1.9 Charges 2.7 21.1 4.9 30.2 Payments (5.1 ) (6.6 ) (16.9 ) (14.1 ) Balance as of end of period $ 2.6 $ 18.0 $ 2.6 $ 18.0 During the three and nine months ended March 28, 2020 , we recorded $2.7 million and $4.9 million , respectively, in restructuring and related charges in our condensed consolidated statements of operations. The charges were mainly attributable to severance charges associated with the decision to move certain manufacturing from San Jose, California to our facility in Thailand. During the three and nine months ended March 30, 2019 , we recorded $21.1 million and $30.2 million , respectively, in restructuring and related charges in our condensed consolidated statements of operations, primarily attributable to severance and employee related benefits associated with the wind down of operations for Lithium Niobate modulators and Datacom modules resulting in $18.0 million of severance charges and $1.6 million o f lease restructuring charges. During the three and nine months ended March 30, 2019 , we also recorded restructuring charges primarily associated with acquisition related synergies. In addition, the nine month period charges included severance and employee related benefits associated with Oclaro’s executive severance and retention agreements. These retention agreements provided, under certain circumstances, for payments and benefits upon an involuntary termination of employment. Any changes in the estimates of executing our restructuring activities will be reflected in our future results of operations.

Income Taxes

Income Taxes	9 Months Ended
	Mar. 28, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Note 15. Income Taxes 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 are 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. We recorded a tax provision of $5.2 million and $19.6 million for the three and nine months ended March 28, 2020 , respectively. We recognized a discrete tax benefit of $4.1 million during the three months ended March 28, 2020 from the release of uncertain tax positions related to the fiscal 2016 U.S. federal income tax return as a result of the expiration of statute of limitations during the quarter. Our estimated effective tax rate for fiscal 2020 differs from the 21% U.S. statutory rate primarily due to the income tax benefit of the earnings of our foreign subsidiaries being taxed at rates that differ from the U.S. statutory rate as well as the U.S. federal R&D and foreign tax credits, partially offset by the income tax expense from non-deductible stock-based compensation and the tax effect of Global Intangible Low-Taxed Income (“GILTI”), Base Erosion and Anti-Abuse Tax (“BEAT”), and subpart F inclusion. As of March 28, 2020 , we had $18.1 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 commencement, resolution and closure of tax audits is highly unpredictable. Although it is possible that certain ongoing tax audits may be concluded within the next 12 months, we cannot reasonably estimate the impact to tax expense and net income from tax exams that could be resolved or closed within the next 12 months. Subject to audit timing and uncertainty, we expect our unrecognized tax benefit amount that could affect the effective tax rate to decrease by $1.2 million over the next 12 months. We believe that we have adequately provided under GAAP for potential outcomes related to our tax audits. However, there can be no assurances as to the possible outcomes or any related financial statement effect thereof. On June 7, 2019, the U.S. Court of Appeals for the Ninth Circuit, reversing a previous decision of the U.S. Tax Court, held that the U.S. Treasury Department’s regulations requiring the inclusion of stock-based compensation expense in a taxpayer’s cost-sharing calculations were valid. On November 12, 2019, the U.S. Court of Appeals for the Ninth Circuit denied the en banc rehearing request filed by the taxpayer on July 22, 2019. Our financial statements have been prepared consistent with this outcome, but we will continue to monitor any ongoing developments, including a potential appeal to the U.S. Supreme Court, to determine if future changes are required. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (“CARES Act”) was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, permits NOL carryovers and carrybacks to offset 100% of taxable income for taxable years beginning before 2021. In addition, the CARES Act contains modifications on the limitation of business interest for tax years beginning in 2019 and 2020 and accelerates a corporation’s ability to recover AMT refundable credits. The Company is currently evaluating the impact of the CARES Act, but at present does not expect that the provisions of the CARES Act would result in a material cash benefit.

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Mar. 28, 2020
Share-based Payment Arrangement [Abstract]
Stockholders' Equity	Note 16. Stockholders' Equity Description of Lumentum Stock-Based Benefit Plans Equity Incentive Plan As of March 28, 2020 , we had 2.4 million shares subject to stock options, restricted stock units, restricted stock awards, and performance stock units issued and outstanding under the 2015 Equity Incentive Plan (the “2015 Plan”). Restricted stock units, restricted stock awards and performance stock units are performance-based, time-based or a combination of both. The fair value of these grants is based on the closing market price of our common stock on the date of award. As of March 28, 2020 , 3.6 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 are 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 . Employee Stock Purchase Plan Our 2015 Employee Stock Purchase Plan (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. 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, 1.9 million shares remained available for issuance as of March 28, 2020 . Stock-Based Compensation Expense The impact on our results of operations of recording stock-based compensation by function for the three and nine months ended March 28, 2020 was as follows (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Cost of sales $ 4.3 $ 3.2 $ 12.6 $ 11.7 Research and development 4.2 4.5 12.1 10.7 Selling, general and administrative 10.7 8.3 31.4 34.1 Total stock-based compensation $ 19.2 $ 16.0 $ 56.1 $ 56.5 Total income tax benefit associated with stock-based compensation recognized in our consolidated statements of operations during the years presented was as follows (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Income tax benefit associated with stock-based compensation $ 2.4 $ 2.1 $ 9.0 $ 8.8 Approximately $3.0 million and $3.5 million of stock-based compensation was capitalized to inventory as of March 28, 2020 and June 29, 2019 , respectively. Stock Award Activity The following table summarizes our awards activity for the nine months ended March 28, 2020 (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 Weighted-Average Grant Date Fair Value per Share Balance as of June 29, 2019 2.2 $ 52.4 — $ 32.5 0.2 $ 56.0 Granted 1.0 59.3 — — 0.2 61.9 Vested/Exercised (1.0 ) 52.1 — 32.5 (0.1 ) 54.6 Canceled (0.2 ) 51.7 — — — 57.3 Balance as of March 28, 2020 2.0 $ 55.6 — $ — 0.3 $ 60.2 As of March 28, 2020 , $111.6 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 1.9 years . A summary of awards available for grant is as follows (in millions) : Awards Available for Grant Balance as of June 29, 2019 4.7 Granted (1.2 ) Canceled 0.1 Balance as of March 28, 2020 3.6 Employee Stock Purchase Plan Activity The 2015 Purchase Plan expense for each of the three months ended March 28, 2020 and March 30, 2019 was $0.8 million and $1.1 million , respectively. The 2015 Purchase Plan expense for the nine months ended March 28, 2020 and March 30, 2019 was $2.5 million and $2.9 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 and nine months ended March 28, 2020 there were 0.1 million 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 each of the three and nine months ended March 28, 2020 and March 30, 2019 , the assumptions used to estimate the fair value of the 2015 Purchase Plan shares to be issued were as follows: March 28, 2020 March 30, 2019 Expected term (years) 0.5 0.5 Expected volatility 44.6 % 71.3 % Risk-free interest rate 1.59 % 2.52 % Dividend yield — % — % Repurchase and Retirement of Common Stock In December 2019, concurrently with the issuance of the 2026 Notes, we repurchased 2.9 million shares of our common stock in privately negotiated transactions at an average price of $69.68 per share for an aggregate purchase price of $200 million . These shares were retired immediately.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Mar. 28, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Note 17. Commitments and Contingencies Purchase Obligations Purchase obligations of $257.2 million as of March 28, 2020 , 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 components 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 and nine months ended March 28, 2020 and March 30, 2019 ( in millions ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Balance as of beginning of period $ 6.8 $ 9.7 $ 7.5 $ 6.6 Warranties assumed in Oclaro acquisition — — — 3.8 Provision for warranty 0.7 1.5 2.5 3.4 Utilization of reserve (2.1 ) (1.4 ) (4.6 ) (4.0 ) Balance as of end of period $ 5.4 $ 9.8 $ 5.4 $ 9.8 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. 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. We have recorded $1.0 million of litigation contingency in other current liabilities on the condensed consolidated balance sheet as of March 28, 2020 . Merger Litigation In connection with our acquisition of Oclaro, seven lawsuits were filed by purported stockholders of Oclaro challenging the proposed merger (the “Merger”). Two of the seven suits were putative class actions filed against Oclaro, its directors, Lumentum, Prota Merger Sub, Inc. and Prota Merger, LLC: Nicholas Neinast v. Oclaro, Inc., et al., No. 3:18-cv-03112-VC, in the United States District Court for the Northern District of California (filed May 24, 2018) (the “Neinast Lawsuit”); and Adam Franchi v. Oclaro, Inc., et al., No. 1:18-cv-00817-GMS, in the United States District Court for the District of Delaware (filed June 9, 2018) (the “Franchi Lawsuit”). Both the Neinstat Lawsuit and the Franchi Lawsuit were voluntarily dismissed with prejudice. The other five suits, styled as Gerald F. Wordehoff v. Oclaro, Inc., et al., No. 5:18-cv-03148-NC (the “Wordehoff Lawsuit”), Walter Ryan v. Oclaro, Inc., et al., No. 3:18-cv-03174-VC (the “Ryan Lawsuit”), Jayme Walker v. Oclaro, Inc., et al., No. 5:18-cv-03203-EJD (the “Walker Lawsuit”), Kevin Garcia v. Oclaro, Inc., et al., No. 5:18-cv-03262-VKD (the “Garcia Lawsuit”), and SaiSravan B. Karri v. Oclaro, Inc., et al., No. 3:18-cv-03435-JD (the “Karri Lawsuit” and, together with the other six lawsuits, the “Lawsuits”), were filed in the United States District Court for the Northern District of California on May 25, 2018, May 29, 2018, May 30, 2018, May 31, 2018, and June 9, 2018, respectively. These five Lawsuits named Oclaro and its directors as defendants only and did not name Lumentum. The Wordehoff, Ryan, Walker, and Garcia Lawsuits have been voluntarily dismissed, and the Wordehoff, Ryan, and Walker dismissals were with prejudice. The Karri Lawsuit has not yet been dismissed. The Ryan Lawsuit was, and the Karri Lawsuit is, a putative class action. The Lawsuits generally alleged, among other things, that Oclaro and its directors violated Section 14(a) of the Securities Exchange Act of 1934, as amended (the “Exchange Act”), and Rule 14a-9 promulgated thereunder by disseminating an incomplete and misleading Form S-4, including proxy statement/prospectus. The Lawsuits further alleged that Oclaro’s directors violated Section 20(a) of the Exchange Act by failing to exercise proper control over the person(s) who violated Section 14(a) of the Exchange Act. The remaining Lawsuit (the Karri Lawsuit) currently purports to seek, among other things, damages to be awarded to the plaintiff and any class, if a class is certified, and litigation costs, including attorneys’ fees. A lead plaintiff and counsel has been selected, and an amended complaint was filed on April 15, 2019, which also names Lumentum as a defendant. A motion to dismiss the amended complaint has been fully briefed and is currently pending, and defendants intend to defend the Karri Lawsuit vigorously. 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 March 28, 2020 , 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. In connection with our acquisition of Oclaro, we recorded $1.1 million in Malaysia Goods and Services Tax (“GST”) refund claims within prepaid expenses and other current assets in our condensed consolidated balance sheet. The refund claim represents an initial claim of $2.5 million of GST, net of reserves, that was previously denied by the Malaysian tax authorities in 2016. During the nine months ended March 28, 2020

Operating Segments and Geograph

Operating Segments and Geographic Information	9 Months Ended
	Mar. 28, 2020
Segment Reporting [Abstract]
Operating Segments and Geographic Information	Note 18. 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 and data communications (“Telecom and Datacom”), and consumer and industrial (“Consumer and Industrial”), and include product lines from the recent acquisition of Oclaro. 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 Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Net revenue: OpComms $ 359.3 $ 377.9 $ 1,184.8 $ 1,013.4 Lasers 43.5 55.0 125.7 147.3 Net revenue $ 402.8 $ 432.9 $ 1,310.5 $ 1,160.7 Gross profit: OpComms $ 161.8 $ 143.5 $ 550.1 $ 397.5 Lasers 21.6 25.3 56.2 63.6 Total segment gross profit 183.4 168.8 606.3 461.1 Unallocated corporate items: Stock-based compensation (4.3 ) (3.2 ) (12.6 ) (11.7 ) Amortization of acquired intangibles (13.9 ) (28.1 ) (38.8 ) (33.3 ) Amortization of fair value adjustments (1.5 ) (14.5 ) (5.8 ) (15.8 ) Inventory and fixed asset write down due to product lines exit (2.3 ) (19.4 ) (6.0 ) (19.4 ) Integration related costs 0.3 (2.8 ) (3.1 ) (2.8 ) Other charges (1) (4.0 ) (12.5 ) (25.5 ) (39.0 ) Gross profit $ 157.7 $ 88.3 $ 514.5 $ 339.1 (1) “Other charges” of unallocated corporate items for the three and nine months ended March 28, 2020 primarily include costs of transferring product lines to new production facilities, including Thailand of $0.4 million and $8.5 million , respectively. We also incurred excess and obsolete inventory charges driven by the decline in demand from Huawei of $0.1 million and $12.8 million during the three and nine months ended March 28, 2020 . In addition, there were expenses of $1.6 million related to COVID-19 outbreak during the three and nine months ended March 28, 2020 , which include incremental costs for payroll expense such as overtime pay, facilities costs such as gloves, masks and temperature gauges, and under-utilized capacity at certain facilities, in which manufacturing output was impacted. These COVID-19 related costs are offset by benefits realized from government credits for employers’ payroll tax. During the three and nine months ended March 30, 2019 , “other charges” of unallocated corporate items included costs of transferring product lines to Thailand of $12.0 million and $38.7 million , respectively. Disaggregation of Revenue We disaggregate revenue by product and by geography. We do not present other levels of disaggregation, such as by type of products, customer, markets, contracts, duration of contracts, timing of transfer of control and sales channels, as this information is not used by our CODM to manage the business. 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 Telecom and Datacom, and Consumer and Industrial markets which accounted for 10% or more of our total net revenue during the periods presented ( in millions, except percentage data ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 OpComms: Telecom and Datacom $ 251.0 62.3 % $ 300.7 69.5 % $ 765.4 58.4 % $ 683.7 58.9 % Consumer and Industrial 108.3 26.9 77.2 17.8 419.4 32.0 329.7 28.4 Total OpComms $ 359.3 89.2 % $ 377.9 87.3 % $ 1,184.8 90.4 % $ 1,013.4 87.3 % Lasers 43.5 10.8 55.0 12.7 125.7 9.6 147.3 12.7 Total Revenue $ 402.8 $ 432.9 $ 1,310.5 $ 1,160.7 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 Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Americas: United States $ 38.6 9.6 % $ 29.7 6.9 % $ 118.9 9.1 % $ 72.3 6.3 % Mexico 33.2 8.2 53.5 12.3 88.3 6.7 164.8 14.2 Other Americas 1.4 0.3 0.9 0.2 3.2 0.3 2.7 0.2 Total Americas $ 73.2 18.1 % $ 84.1 19.4 % $ 210.4 16.1 % $ 239.8 20.7 % Asia-Pacific: Hong Kong $ 125.9 31.3 % $ 124.1 28.6 % $ 404.2 30.8 % $ 289.6 25.0 % South Korea 63.3 15.7 23.6 5.5 239.9 18.3 154.9 13.3 Japan 35.8 8.9 50.0 11.6 110.4 8.4 129.2 11.1 Other Asia-Pacific 77.2 19.2 98.4 22.7 248.8 19.0 234.4 20.2 Total Asia-Pacific $ 302.2 75.1 % $ 296.1 68.4 % $ 1,003.3 76.5 % $ 808.1 69.6 % EMEA $ 27.4 6.8 % $ 52.7 12.2 % $ 96.8 7.4 % $ 112.8 9.7 % Total net revenue $ 402.8 $ 432.9 $ 1,310.5 $ 1,160.7 During the three and nine months ended March 28, 2020 , net revenue from customers outside the United States, based on customer shipping location, represented 90.4% and 90.9% of net revenue, respectively. During the three and nine months ended March 30, 2019 , net revenue from customers outside the United States, based on customer shipping location, represented 93.1% and 93.7% of net revenue, respectively. The increase in our net revenue from the United States during the nine months ended March 28, 2020 compared to the nine months ended March 30, 2019 is mainly due to the acquisition of Oclaro, which had a higher concentration of customers who manufacture in the United States, as well as a change in shipment destination for some shipments to one of our large customers from Mexico to the United States. During the nine months ended March 28, 2020 , our net revenue from South Korea increased due to higher demand in 3D sensing products, while net revenue from Hong Kong increased as a result of higher sales of 3D sensing products and Datacom chips. Transaction Price Allocated to the Remaining Performance Obligations The following table includes estimated revenue expected to be recognized in the future for backlog related performance obligations that are unsatisfied as of March 28, 2020 ( in millions ): Less than 1 year 1-2 years Greater than 2 years Total Performance obligations $513.9 $32.7 $— $546.6 Contract Balances The following table reflects the changes in contract balances as of March 28, 2020 ( in millions, except percentages ): Contract balances Balance sheet location March 28, 2020 June 29, 2019 Change Percentage Change Accounts receivable, net Accounts receivable, net $261.8 $238.0 $23.8 10.0% Deferred revenue and customer deposits Other current liabilities $1.7 $2.9 $(1.2) (41.4)% During the three and nine months ended March 28, 2020 , our net revenue was concentrated with two customers, who collectively accounted for 37% and 42% of our total net revenue, respectively. During the three and nine months ended March 30, 2019 , our net revenue was concentrated with three customers, who collectively accounted for 44% and 52% of our total net revenue, respectively. As of March 28, 2020 and June 29, 2019 , our accounts receivable balance was concentrated with two and three customers, who collectively represented 27% and 44% of gross accounts receivable, respectively. Long-lived assets, namely net property, plant and equipment, net, were identified based on the physical location of the assets in the corresponding geographic areas as of the periods indicated (in millions) : March 28, 2020 June 29, 2019 Property, plant and equipment, net United States $ 145.8 $ 156.2 Thailand 135.3 157.1 China 43.3 33.5 Japan 29.2 28.3 Other countries 56.5 58.2 Total long-lived assets $ 410.1 $ 433.3 We purchase a substantial portion of our inventory from contract manufacturers and vendors located primarily in Taiwan, Thailand, and Malaysia. During the three and nine months ended March 28, 2020 , net inventory purchases which represented 10% or greater of total net purchases, were concentrated with two contract manufacturers, who collectively accounted for 88% and 85% of total net inventory purchases, respectively. During the three and nine months ended March 30, 2019 , net inventory purchases were concentrated with three contract manufacturers, who collectively accounted for 85% and 85% of total net inventory purchases, respectively.

Description of Business and S_2

Description of Business and Summary of Significant Accounting Policies (Policies)	9 Months Ended
	Mar. 28, 2020
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. Those policies are inventory valuation, revenue recognition, income taxes, long-lived asset valuation, business combinations and goodwill. On December 10, 2018, we completed our merger with Oclaro, Inc. (“Oclaro”), a provider of optical components and modules for the long-haul, metro and data center markets. Our condensed consolidated financial statements include the operating results of Oclaro beginning from the date of acquisition. Refer to “ Note 4. Business Combinations ” for further discussion of the merger. The COVID-19 pandemic has created and may continue to create significant uncertainty in global financial markets, which has disrupted and harmed, and may continue to disrupt and harm, the Company's business, financial condition, and results of operations. The extent of the impact of COVID-19 on the Company's operational and financial performance will depend on certain developments, including but not limited to the duration and spread of the outbreak, duration of local, state and federal issued public health orders in each jurisdiction where we operate or in which our customers and suppliers operate, impact on our customers and our sales cycles, impact on our supply chain and manufacturing partners, impact on our employees and impact on regional and worldwide economies and financial markets in general, all of which are uncertain and cannot be predicted.
Fiscal Years	Fiscal Years We utilize a 52-53 week fiscal year ending on the Saturday closest to June 30th. Every fifth or sixth fiscal year will have a 53-week period. The additional week in a 53-week year is added to the third quarter, making such quarter consist of 14 weeks. Our fiscal 2021 will be a 53-week year. Our fiscal 2020 is a 52-week year ending on June 27, 2020 , with the quarter ended March 28, 2020 being a 13-week quarterly period. Our fiscal 2019 was a 52-week year that ended on June 29, 2019 , with the quarter ended March 30, 2019 being a 13-week quarterly period.
Principles of Consolidation	Principles of Consolidation
Reclassification	Certain prior period amounts have been reclassified to conform to the current period presentation, including the reclassification of capital lease obligations that existed as of June 29, 2019 to finance lease liabilities within other current liabilities and other non-current liabilities in our condensed consolidated balance sheets, as a result of the adoption of the new accounting guidance for leases. Refer to “ Note 2. Recently Issued Accounting Pronouncements ” for details. The reclassification of the prior period amounts did not impact previously reported condensed consolidated financial statements.
Accounting Policies, Accounting Pronouncements Recently Adopted and Accounting Pronouncements Not Yet Effective	Accounting Policies The accompanying 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 29, 2019 . Except for the accounting policies for lease accounting as a result of the adoption of Accounting Standards Update (“ASU”) 2016-02, Leases (Topic 842) , there have been no significant changes to our significant accounting policies as of and for the three months ended March 28, 2020 , as compared to the significant accounting policies described in our Annual Report on Form 10-K for the year ended June 29, 2019 . Adoption of Leases (Topic 842) On June 30, 2019, the first day of fiscal year 2020, we adopted Topic 842, using the modified retrospective transition approach. Refer to “ Note 2. Recently Issued Accounting Pronouncements ” regarding the impact of adoption. We determine if an arrangement is a lease at inception for arrangements with an initial term of more than 12 months, and classify it as either finance or operating. Finance leases are generally those that allow us to substantially utilize or pay for the entire asset over its estimated useful life. Finance leases are recorded in property, plant and equipment, net, and finance lease liabilities within other current and other non-current liabilities on our condensed consolidated balance sheets. We have lease arrangements with lease and non-lease components, and the non-lease components for our finance leases are accounted for separately, based on estimated stand-alone values, and are not included in the initial measurement of our finance lease assets and corresponding liabilities. Finance lease assets are amortized in operating expenses on a straight-line basis over the shorter of the estimated useful lives of the assets or the lease term, with the interest component included in interest expense and recognized using the effective interest method over the lease term. Operating leases are recorded in operating lease right-of-use assets, net, and operating lease liabilities, current and non-current on our condensed consolidated balance sheets. For operating leases of buildings, we account for non-lease components, such as common area maintenance, as a component of the lease, and include it in the initial measurement of our operating lease assets and corresponding liabilities. Operating lease assets are amortized on a straight-line basis in operating expenses over the lease term. Our lease liabilities are recognized based on the present value of the remaining fixed lease payments, over the lease term, using a discount rate of similarly secured borrowings available to us. For the purpose of lease liability measurement, we consider only payments that are fixed and determinable at the time of commencement. Any variable payments that depend on an index or rate are expensed as incurred. Our lease terms may include options to extend when it is reasonably certain that we will exercise that option. Our lease assets also include any lease payments made and exclude any lease incentives received prior to commencement. Our lease assets are tested for impairment in the same manner as long-lived assets used in operations. We generally recognize sublease income on a straight-line basis over the sublease term. Accounting Pronouncements Recently Adopted Effective June 30, 2019, we adopted Topic 842, using the modified retrospective transition approach. We applied the new guidance to all leases existing as of the date of adoption. Our reported results beginning with the first quarter of fiscal 2020 reflect the application of Topic 842, while prior period amounts have not been adjusted and continue to be reported in accordance with our historical accounting under Topic 840. We elected the practical expedient package permitted under the transition approach. As such, we did not reassess whether any expired or existing contracts are or contain leases, we did not reassess our historical lease classification, and we did not reassess our initial direct costs for any leases that existed prior to June 30, 2019. We have also elected to combine lease and non-lease components at a portfolio level for our operating leases of buildings and not to report leases with an initial term of 12 months or less on our balance sheet. As of the date of adoption, we recognized operating lease assets of $91.5 million , with corresponding operating lease liabilities of $81.5 million on the condensed consolidated balance sheets. The difference between the operating lease right-of-use assets and operating lease liabilities primarily represents the existing asset recognized in relation to the favorable terms of an operating lease acquired through a business combination offset by our deferred rent and ASC 420 “cease-use” balances. All existing leases that were classified as capital leases under Topic 840 are classified as finance leases under the new guidance. As of adoption, we recognized finance lease assets of $12.4 million in property, plant and equipment, net, with corresponding finance lease liabilities of $12.4 million on the condensed consolidated balance sheets. For further information regarding the impact of Topic 842 adoption, see “ Note 1. Description of Business and Summary of Significant Accounting Policies ” and “ Note 9. Leases ”. 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 U.S. Tax Cuts and Jobs Act of 2017 (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. We adopted ASU 2018-02 in the first quarter of fiscal 2020 with no impact to our condensed 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 early adopted ASU 2017-04 in our first quarter of fiscal 2020. The implementation of ASU 2017-04 did not have an impact on our condensed consolidated financial statements. Accounting Pronouncements Not Yet Effective In December 2019, FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes (Topic 740), which is intended to simplify various aspects related to accounting for income taxes by removing certain exceptions to the general principles in Topic 740 and which also clarifies and amends existing guidance to improve consistent application. ASU 2019-12 is effective for us at the beginning of fiscal 2022, including interim periods within that reporting period, although early adoption is permitted. We are currently evaluating the impact of ASU 2019-12 on our condensed 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 post-retirement benefit plans. The new guidance is effective for fiscal years ending after December 15, 2020, with early adoption 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 condensed 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, with early adoption permitted. ASU 2018-13 requires that certain of the amendments be applied prospectively, while other amendments should be applied retrospectively to all periods presented. ASU 2018-13 is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of ASU 2018-13 on our condensed consolidated financial statements and related disclosures. 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. This standard requires capitalization of the implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. Further, the standard also requires the Company to expense the capitalized implementation costs of a hosting arrangement over the term of the hosting arrangement. This standard is effective for us in our first quarter of fiscal 2021. Early adoption is permitted. The adoption of this standard is not expected to have a significant impact on our consolidated financial statements. In June 2016, FASB issued ASU 2016-13, Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments and a subsequent amendment, ASU 2018-19 (collectively, Topic 326). Topic 326 requires measurement and recognition of expected credit losses for financial assets held. Topic 326 is effective for annual periods beginning after December 15, 2019, including interim periods within those periods, with early adoption permitted. ASU 2016-13 is effective for us in our first quarter of fiscal 2021. We are currently evaluating the impact of our pending adoption of Topic 326 on our condensed consolidated financial statements.
Fair Value Measurements	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. 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 our 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 our 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. Our procedures include controls to ensure that appropriate fair values are recorded, including comparing the fair values obtained from our pricing service against fair values obtained from another independent source.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Mar. 28, 2020
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 Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Basic Earnings per Common Share Net income (loss) $ 43.4 $ (74.3 ) $ 140.1 $ (10.6 ) Less: Cumulative dividends on Series A Preferred Stock — — — (0.3 ) Less: Earnings allocated to Series A Preferred Stock — — — (1.2 ) Net income (loss) attributable to common stockholders - Basic $ 43.4 $ (74.3 ) $ 140.1 $ (12.1 ) Weighted average common shares outstanding including Series A Preferred Stock 74.8 76.2 76.2 69.4 Less: Weighted average Series A Preferred Stock — — — (0.7 ) Basic weighted average common shares outstanding 74.8 76.2 76.2 68.7 Net income (loss) per share attributable to common stockholders - Basic $ 0.58 $ (0.98 ) $ 1.84 $ (0.18 ) Diluted Earnings per Common Share Net income (loss) attributable to common stockholders - Basic $ 43.4 $ (74.3 ) $ 140.1 $ (12.1 ) Net income (loss) attributable to common stockholders - Diluted $ 43.4 $ (74.3 ) $ 140.1 $ (12.1 ) Weighted average common shares outstanding for basic earnings per common share 74.8 76.2 76.2 68.7 Effect of dilutive securities from 2015 Equity Incentive Plan 1.0 — 0.8 — Shares issuable assuming conversion of the 2024 Notes 1.7 — 0.7 — Diluted weighted average common shares outstanding 77.5 76.2 77.7 68.7 Net income (loss) per share attributable to common stockholders - Diluted $ 0.56 $ (0.98 ) $ 1.80 $ (0.18 )

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Mar. 28, 2020
Business Combinations [Abstract]
Schedule of Business Acquisitions	Our allocation of the purchase price of Oclaro based on the estimated fair values of the assets acquired and liabilities assumed is as follows ( in millions ): As Previously Reported on June 29, 2019 Cash and cash equivalents $ 345.0 Accounts receivable, net 68.0 Inventories 155.0 Prepayments and other current assets 33.7 Property, plant and equipment, net 134.7 Intangibles 444.0 Deferred income tax asset 42.6 Other non-current assets 16.6 Accounts payable (57.8 ) Accrued payroll and related expenses (11.4 ) Accrued expenses (8.3 ) Other current liabilities (6.1 ) Deferred tax liability (75.8 ) Other non-current liabilities (12.9 ) Goodwill 357.6 Total purchase price $ 1,424.9 The total fair value of consideration given in connection with the acquisition of Oclaro consisted of the following: Shares Per Share Total Consideration (in millions) Cash paid for outstanding Oclaro common stock $ 964.8 Lumentum common shares issued to Oclaro stockholders 10,941,436 $ 41.80 457.4 Replacement equity awards for Oclaro equity awards 2.7 Total consideration $ 1,424.9
Pro Forma Financial Information	The unaudited supplemental pro forma financial information for the period presented is as follows ( in millions ): Nine Months Ended March 30, 2019 Net revenue $ 1,374.8 Net loss (18.2 )

Cash, Cash Equivalents and Sh_2

Cash, Cash Equivalents and Short-term Investments (Tables)	9 Months Ended
	Mar. 28, 2020
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 March 28, 2020: Cash $ 121.3 $ — $ — $ 121.3 Cash equivalents: Commercial paper 72.6 — — 72.6 Corporate debt securities 3.0 — — 3.0 Money market funds 426.2 — — 426.2 U.S. Treasury securities 65.1 0.1 — 65.2 Total cash and cash equivalents $ 688.2 $ 0.1 $ — $ 688.3 Short-term investments: Certificates of deposit $ 4.4 $ — $ — $ 4.4 Commercial paper 88.1 — — 88.1 Corporate debt securities 343.2 0.2 (2.5 ) 340.9 Foreign government bonds 4.0 — — 4.0 U.S. Agency securities 23.0 0.1 — 23.1 U.S. Treasury securities 300.7 1.9 — 302.6 Total short-term investments $ 763.4 $ 2.2 $ (2.5 ) $ 763.1 June 29, 2019: Cash $ 213.8 $ — $ — $ 213.8 Cash equivalents: Commercial paper 37.4 — — 37.4 Money market funds 168.1 — — 168.1 U.S. Treasury securities 13.3 — — 13.3 Total cash and cash equivalents $ 432.6 $ — $ — $ 432.6 Short-term investments: Certificates of deposit $ 1.9 $ — $ — $ 1.9 Commercial paper 22.3 — — 22.3 Asset-backed securities 54.9 0.2 — 55.1 Corporate debt securities 207.6 0.9 (0.1 ) 208.4 Municipal bonds 1.3 — — 1.3 Mortgage-backed securities 6.6 — — 6.6 Foreign government bonds 6.2 — — 6.2 U.S. Agency securities 4.6 — — 4.6 U.S. Treasury securities 29.4 0.1 — 29.5 Total short-term investments $ 334.8 $ 1.2 $ (0.1 ) $ 335.9
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 March 28, 2020: U.S. Agency securities $ 8.0 $ — $ — $ — $ 8.0 $ — Certificates of deposit 2.5 — — — 2.5 — Commercial paper 55.2 — — — 55.2 — Corporate debt securities 301.1 (2.5 ) — — 301.1 (2.5 ) Total $ 366.8 $ (2.5 ) $ — $ — $ 366.8 $ (2.5 ) June 29, 2019: Asset-backed securities $ 4.2 $ — $ 5.9 $ — $ 10.1 $ — Corporate debt securities 9.6 — 35.9 (0.1 ) 45.5 (0.1 ) Foreign government bonds — — 2.1 — 2.1 — U.S. government bonds 6.9 — — — 6.9 — Total $ 20.7 $ — $ 43.9 $ (0.1 ) $ 64.6 $ (0.1 )
Classification of investments in debt securities by contractual maturities	The following table classifies our short-term investments by contractual maturities ( in millions ): March 28, 2020 June 29, 2019 Amortized Cost Fair Value Amortized Cost Fair Value Due in 1 year $ 720.1 $ 720.0 $ 178.9 $ 179.1 Due in 1 year through 5 years 43.3 43.1 148.1 149.0 Due in 5 years through 10 years — — 6.0 6.0 Due after 10 years — — 1.8 1.8 $ 763.4 $ 763.1 $ 334.8 $ 335.9

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Mar. 28, 2020
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 March 28, 2020: (1) Assets: Cash equivalents: Commercial paper $ — $ 72.6 $ — $ 72.6 Corporate debt securities — 3.0 — 3.0 Money market funds 426.2 — — 426.2 U.S. Treasury securities 65.2 — — 65.2 Short-term investments: Certificates of deposit — 4.4 — 4.4 Commercial paper — 88.1 — 88.1 Corporate debt securities — 340.9 — 340.9 Foreign government bonds — 4.0 — 4.0 U.S. Agency securities — 23.1 — 23.1 U.S. Treasury securities 302.6 — — 302.6 Total assets $ 794.0 $ 536.1 $ — $ 1,330.1 (1) Excludes $121.3 million in cash held in our bank accounts at March 28, 2020 . Level 1 Level 2 Level 3 Total June 29, 2019: (1) Assets: Cash equivalents: Commercial paper $ — $ 37.4 $ — $ 37.4 Money market funds 168.1 — — 168.1 U.S. Treasury securities 13.3 — — 13.3 Short-term investments: Certificates of deposit — 1.9 — 1.9 Commercial paper — 22.3 — 22.3 Asset-backed securities — 55.1 — 55.1 Corporate debt securities — 208.4 — 208.4 Municipal bonds — 1.3 — 1.3 Mortgage-backed securities — 6.6 — 6.6 Foreign government bonds — 6.2 — 6.2 U.S. Agency securities — 4.6 — 4.6 U.S. Treasury securities 29.5 — — 29.5 Total assets $ 210.9 $ 343.8 $ — $ 554.7 Other accrued liabilities: Acquisition contingency $ — $ — $ 2.7 $ 2.7 Total other accrued liabilities $ — $ — $ 2.7 $ 2.7 (1) Excludes $213.8 million in cash held in our bank accounts as of June 29, 2019 .

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	9 Months Ended
	Mar. 28, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of components of inventories	The components of inventories were as follows ( in millions ): March 28, 2020 June 29, 2019 Raw materials and purchased parts $ 55.4 $ 78.3 Work in process 67.9 72.5 Finished goods 49.4 78.0 Inventories (1) $ 172.7 $ 228.8 (1) The inventory balance as of June 29, 2019 includes $5.7 million , net of amortization, related to the inventory step-up adjustment from the Oclaro acquisition. As of March 28, 2020 , the inventory step-up adjustment from the Oclaro acquisition was fully amortized.
Schedule of components of prepayments and other current assets	The components of prepayments and other current assets were as follows ( in millions ): March 28, 2020 June 29, 2019 Prepayments $ 29.7 $ 32.4 Vendor receivable 29.8 36.3 Value added tax receivable 11.5 11.9 Advances to contract manufacturers — 8.7 Assets held-for-sale 1.3 4.9 Other current assets 4.8 3.3 Prepayments and other current assets $ 77.1 $ 97.5
Schedule of operating lease, right-of-use assets	Operating lease right-of-use assets, net were as follows ( in millions ): March 28, 2020 Operating lease right-of-use assets $ 90.3 Less: accumulated amortization (8.6 ) Operating lease right-of-use assets, net $ 81.7
Schedule of components of property, plant and equipment, net	The components of property, plant and equipment, net were as follows ( in millions ): March 28, 2020 June 29, 2019 Land $ 44.2 $ 44.2 Buildings and improvement 112.9 103.7 Machinery and equipment (1) 514.1 500.5 Computer equipment and software 25.6 25.4 Furniture and fixtures 6.6 4.9 Leasehold improvements 28.1 31.2 Finance lease right-of-use assets (1) 28.1 16.0 Construction in progress 53.0 46.8 812.6 772.7 Less: Accumulated depreciation (1) (402.5 ) (339.4 ) Property, plant and equipment, net $ 410.1 $ 433.3 (1) Included in the table above is our equipment acquired under finance leases. As of March 28, 2020 and June 29, 2019, the accumulated depreciation of finance lease right-of-use assets was $24.2 million and $11.2 million , respectively. For fiscal 2019 in accordance with Topic 842, we have reclassified $16.0 million of equipment acquired under finance leases from machinery and equipment to finance lease right-of-use assets to conform to current period presentation.
Schedule of components of other current liabilities	The components of other current liabilities were as follows (in millions) : March 28, 2020 June 29, 2019 Restructuring accrual and related charges (1) $ 2.6 $ 14.6 Warranty accrual (2) 5.4 7.5 Deferred revenue and customer deposits 1.7 2.9 Finance lease liabilities, current (3) 3.9 0.4 Income tax payable 30.4 8.7 Other current liabilities 2.8 5.1 Other current liabilities $ 46.8 $ 39.2 (1) Refer to “ Note 14. Restructuring and Related Charges .” (2) Refer to “ Note 17. Commitments and Contingencies .” (3) For fiscal 2019 in accordance with Topic 842, we have reclassified amounts from capital lease obligations to finance lease liabilities to conform to current period presentation. In addition to the $3.9 million of finance lease liabilities recorded within other current liabilities as of March 28, 2020 , we also recorded $0.1 million within other non-current liabilities in the condensed consolidated balance sheet. Refer to “ Note 9. Leases .”
Schedule of components of other non-current liabilities	The components of other non-current liabilities were as follows ( in millions ): March 28, 2020 June 29, 2019 Asset retirement obligations $ 4.9 $ 4.5 Pension and related accrual (1) 10.0 7.9 Deferred rent — 2.2 Unrecognized tax benefit 18.1 18.7 Finance lease liabilities, non-current 0.1 — Other non-current liabilities 0.6 0.4 Other non-current liabilities $ 33.7 $ 33.7 (1) We have defined benefit pension plans in Japan, Switzerland, and Thailand. As of March 28, 2020, the projected benefit obligations in Japan, Switzerland, and Thailand were $2.8 million , $4.7 million , and $2.5 million , respectively. As of June 29, 2019 , the projected benefit obligations for Japan and Switzerland were $2.8 million and $5.0 million , respectively. Pension and related accruals as of June 29, 2019 also include $0.1 million attributable to post-retirement benefits for executives.

Leases (Tables)

Leases (Tables)	9 Months Ended
	Mar. 28, 2020
Leases [Abstract]
Lease Costs	The components of lease costs, lease term, and discount rate are as follows: Three Months Ended Nine Months Ended March 28, 2020 March 28, 2020 Finance lease cost ( in millions ): Amortization of right-of-use assets $ 4.8 $ 13.0 Interest — 0.1 Operating lease cost 3.9 11.9 Variable lease cost 0.4 1.5 Short-term lease cost 0.7 1.7 Sublease income (0.7 ) (1.9 ) Total lease cost $ 9.1 $ 26.3 Weighted average remaining lease term ( in years ): Operating leases 8.9 Finance leases 0.7 Weighted average discount rate: Operating leases 3.65 % Finance leases 4.38 %
Lease Maturity	As of March 28, 2020 , maturities of our operating and finance lease liabilities, which do not include short-term leases and variable lease payments, were as follows ( in millions ): Fiscal Years Operating Leases (1) Finance Leases Total Remainder of 2020 $ 3.3 $ 3.4 $ 6.7 2021 13.1 0.6 13.7 2022 12.3 — 12.3 2023 11.1 — 11.1 2024 9.4 — 9.4 Thereafter 31.4 — 31.4 Total minimum lease payments $ 80.6 $ 4.0 $ 84.6 Less: amount representing interest (10.0 ) — (10.0 ) Present value of total lease liabilities $ 70.6 $ 4.0 $ 74.6 (1) Non-cancellable sublease proceeds for the remainder of fiscal 2020, and fiscal 2021, 2022, and 2023 of $0.7 million , $2.4 million , $2.2 million , and $0.6 million , respectively, are not included in the table above.
Lease Maturity	As of March 28, 2020 , maturities of our operating and finance lease liabilities, which do not include short-term leases and variable lease payments, were as follows ( in millions ): Fiscal Years Operating Leases (1) Finance Leases Total Remainder of 2020 $ 3.3 $ 3.4 $ 6.7 2021 13.1 0.6 13.7 2022 12.3 — 12.3 2023 11.1 — 11.1 2024 9.4 — 9.4 Thereafter 31.4 — 31.4 Total minimum lease payments $ 80.6 $ 4.0 $ 84.6 Less: amount representing interest (10.0 ) — (10.0 ) Present value of total lease liabilities $ 70.6 $ 4.0 $ 74.6 (1) Non-cancellable sublease proceeds for the remainder of fiscal 2020, and fiscal 2021, 2022, and 2023 of $0.7 million , $2.4 million , $2.2 million , and $0.6 million , respectively, are not included in the table above.
Lease Maturity, Prior to 842	Prior to our adoption of Topic 842, future minimum lease payments as of June 29, 2019, which were undiscounted, were net of our sublease income amounts, and included lease and non-lease components, were as follows ( in millions ): Fiscal Years Operating Leases Finance Leases Total 2020 $ 13.9 $ 0.8 $ 14.7 2021 12.1 — 12.1 2022 11.2 — 11.2 2023 11.3 — 11.3 2024 9.8 — 9.8 Thereafter 31.7 — 31.7 Total minimum operating lease payments $ 90.0 $ 0.8 $ 90.8
Lease Maturity, Prior to 842	Prior to our adoption of Topic 842, future minimum lease payments as of June 29, 2019, which were undiscounted, were net of our sublease income amounts, and included lease and non-lease components, were as follows ( in millions ): Fiscal Years Operating Leases Finance Leases Total 2020 $ 13.9 $ 0.8 $ 14.7 2021 12.1 — 12.1 2022 11.2 — 11.2 2023 11.3 — 11.3 2024 9.8 — 9.8 Thereafter 31.7 — 31.7 Total minimum operating lease payments $ 90.0 $ 0.8 $ 90.8

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	9 Months Ended
	Mar. 28, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of changes in goodwill	The following table presents our goodwill balance by the reportable segments as of March 28, 2020 ( in millions) : Optical Communications Commercial Lasers Total Balance as of March 28, 2020 $ 363.5 $ 5.4 $ 368.9
Acquired developed technology and other intangibles	The following tables present details of our other intangibles, including those acquired in connection with the Oclaro acquisition, as of the periods presented ( in millions, except for weighted average remaining amortization period ): March 28, 2020 Gross Carrying Amounts Accumulated Amortization Net Carrying Amounts Weighted average remaining amortization period (years) Acquired developed technologies (1) $ 346.5 $ (161.9 ) $ 184.6 3.5 Customer relationships 149.3 (30.9 ) 118.4 6.7 In-process research and development (1) 35.0 — 35.0 n/a Order backlog 22.0 (22.0 ) — — Other intangibles 2.7 (2.7 ) — — Total intangible assets $ 555.5 $ (217.5 ) $ 338.0 (1) During the three and nine months ended March 28, 2020 , we completed $7 million and $59 million of IPR&D projects, respectively, and reclassified the value assigned to them to acquired developed technologies. The amount will be amortized over the assets’ estimated useful life of 4 to 5 years. June 29, 2019 Gross Carrying Amounts Accumulated Amortization Net Carrying Amounts Weighted average remaining amortization period (years) Acquired developed technologies $ 287.5 $ (125.2 ) $ 162.3 3.8 Customer relationships 149.3 (12.3 ) 137.0 7.5 In-process research and development 94.0 — 94.0 n/a Order backlog 22.0 (19.9 ) 2.1 0.5 Other intangibles 2.7 (2.7 ) — — Total intangible assets $ 555.5 $ (160.1 ) $ 395.4
Details of amortization expense	The following table presents details of amortization for the periods presented (in millions ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Cost of sales $ 13.9 $ 28.1 $ 38.8 $ 33.3 Selling, general and administrative 6.1 3.6 18.6 4.4 Total amortization of intangibles $ 20.0 $ 31.7 $ 57.4 $ 37.7
Estimated future amortization expense	Based on the carrying amount of our acquired developed technologies and other intangibles, excluding IPR&D, as of March 28, 2020 , and assuming no future impairment of the underlying assets, the estimated future amortization is as follows (in millions): Fiscal Years Remainder of 2020 $ 20.3 2021 78.9 2022 76.4 2023 52.9 2024 33.1 Thereafter 41.4 Total future amortization $ 303.0

Debt (Tables)

Debt (Tables)	9 Months Ended
	Mar. 28, 2020
Debt Disclosure [Abstract]
Components of 2024 Notes	Our convertible notes consisted of the following components as of the periods presented ( in millions ): Liability component: March 28, 2020 June 29, 2019 2024 Notes 2026 Notes 2024 Notes Principal $ 450.0 $ 1,050.0 $ 450.0 Unamortized debt discount and debt issuance costs (84.2 ) (309.8 ) (98.1 ) Net carrying amount of the liability component $ 365.8 $ 740.2 $ 351.9
Interest Expense	The following table sets forth interest expense information related to the convertible notes for the periods presented (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Contractual interest expense $ 1.6 $ 0.3 $ 2.3 $ 0.9 Amortization of the debt discount and debt issuance costs 14.0 4.5 24.8 13.2 Total interest expense $ 15.6 $ 4.8 $ 27.1 $ 14.1 The following table sets forth interest expense information related to the term loan for the periods presented (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Contractual interest expense $ — $ 6.2 $ 9.6 $ 10.2 Amortization of the debt issuance costs — 0.4 0.5 0.5 Loss on early extinguishment of debt — — 8.0 — Total interest expense $ — $ 6.6 $ 18.1 $ 10.7
Future Interest and Principal Payments	The future interest and principal payments related to our convertible notes are as follows as of March 28, 2020 (in millions) : Fiscal Years 2024 Notes 2026 Notes Total Remainder of 2020 $ — $ 2.7 $ 2.7 2021 1.1 5.2 6.3 2022 1.1 5.3 6.4 2023 1.1 5.2 6.3 2024 451.2 5.3 456.5 Thereafter — 1,063.1 1,063.1 Total convertible notes payments $ 454.5 $ 1,086.8 $ 1,541.3
Schedule of Term Loan Information	The following table sets forth balance sheet information related to the term loan as of the periods presented ( in millions ): March 28, 2020 June 29, 2019 Principal $ 497.5 $ 500.0 Repayment of principal (497.5 ) (2.5 ) Unamortized value of the debt issuance costs — (8.5 ) Net carrying value $ — $ 489.0 Term loan, current $ — $ 5.0 Term loan, non-current $ — $ 484.0

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Mar. 28, 2020
Equity [Abstract]
Schedule of accumulated other comprehensive income (loss)	The changes in accumulated other comprehensive income (loss) by component and related tax effects for each period presented were as follows ( in millions ): Foreign currency translation adjustments, net of tax (1) Defined benefit obligations, net of tax (2) Unrealized gain (loss) on available-for-sale securities, net of tax (3) Total Beginning balance as of June 29, 2019 (3) $ 9.7 $ (3.5 ) $ 0.9 $ 7.1 Other comprehensive income — — 0.1 0.1 Ending balance as of September 28, 2019 (3) 9.7 (3.5 ) 1.0 7.2 Other comprehensive loss — — (0.2 ) (0.2 ) Ending balance as of December 28, 2019 (3) 9.7 (3.5 ) 0.8 7.0 Other comprehensive loss — — (1.2 ) (1.2 ) Ending balance as of March 28, 2020 (3) $ 9.7 $ (3.5 ) $ (0.4 ) $ 5.8 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 Other comprehensive income (loss) (0.7 ) (0.1 ) 0.1 (0.7 ) Ending balance as of December 29, 2018 9.7 (2.4 ) (1.1 ) 6.2 Other comprehensive income — — 1.3 1.3 Ending balance as of March 30, 2019 $ 9.7 $ (2.4 ) $ 0.2 $ 7.5 (1) In fiscal 2019, as a result of significant changes in economic facts and circumstances, primarily due to the acquisition of Oclaro, we established the functional currency for our worldwide operations as the U.S. dollar. Translation adjustments reported prior to December 10, 2018, remain as a component of accumulated other comprehensive income in our condensed consolidated balance sheets, until all or a part of the investment in the subsidiaries is sold or liquidated. (2) We evaluate the assumptions over the fair value of our defined benefit obligations annually and make changes as necessary. (3) Fiscal 2020 balances of unrealized gain (loss) on available-for-sale securities are net of tax of $0.2 million

Restructuring and Related Cha_2

Restructuring and Related Charges (Tables)	9 Months Ended
	Mar. 28, 2020
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 and nine months ended March 28, 2020 and March 30, 2019 ( in millions ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Balance as of beginning of period $ 5.0 $ 3.5 $ 14.6 $ 1.9 Charges 2.7 21.1 4.9 30.2 Payments (5.1 ) (6.6 ) (16.9 ) (14.1 ) Balance as of end of period $ 2.6 $ 18.0 $ 2.6 $ 18.0

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Mar. 28, 2020
Share-based Payment Arrangement [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 and nine months ended March 28, 2020 was as follows (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Cost of sales $ 4.3 $ 3.2 $ 12.6 $ 11.7 Research and development 4.2 4.5 12.1 10.7 Selling, general and administrative 10.7 8.3 31.4 34.1 Total stock-based compensation $ 19.2 $ 16.0 $ 56.1 $ 56.5
Schedule of income tax benefit associated with stock-based compensation	Total income tax benefit associated with stock-based compensation recognized in our consolidated statements of operations during the years presented was as follows (in millions) : Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Income tax benefit associated with stock-based compensation $ 2.4 $ 2.1 $ 9.0 $ 8.8
Summary of awards activity	The following table summarizes our awards activity for the nine months ended March 28, 2020 (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 Weighted-Average Grant Date Fair Value per Share Balance as of June 29, 2019 2.2 $ 52.4 — $ 32.5 0.2 $ 56.0 Granted 1.0 59.3 — — 0.2 61.9 Vested/Exercised (1.0 ) 52.1 — 32.5 (0.1 ) 54.6 Canceled (0.2 ) 51.7 — — — 57.3 Balance as of March 28, 2020 2.0 $ 55.6 — $ — 0.3 $ 60.2
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 June 29, 2019 4.7 Granted (1.2 ) Canceled 0.1 Balance as of March 28, 2020 3.6
Schedule of assumptions used to estimate fair value	During each of the three and nine months ended March 28, 2020 and March 30, 2019 , the assumptions used to estimate the fair value of the 2015 Purchase Plan shares to be issued were as follows: March 28, 2020 March 30, 2019 Expected term (years) 0.5 0.5 Expected volatility 44.6 % 71.3 % Risk-free interest rate 1.59 % 2.52 % Dividend yield — % — %

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Mar. 28, 2020
Commitments and Contingencies Disclosure [Abstract]
Schedule of changes in warranty reserve	The following table presents the changes in our warranty reserve during the three and nine months ended March 28, 2020 and March 30, 2019 ( in millions ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Balance as of beginning of period $ 6.8 $ 9.7 $ 7.5 $ 6.6 Warranties assumed in Oclaro acquisition — — — 3.8 Provision for warranty 0.7 1.5 2.5 3.4 Utilization of reserve (2.1 ) (1.4 ) (4.6 ) (4.0 ) Balance as of end of period $ 5.4 $ 9.8 $ 5.4 $ 9.8

Operating Segments and Geogra_2

Operating Segments and Geographic Information (Tables)	9 Months Ended
	Mar. 28, 2020
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 Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Net revenue: OpComms $ 359.3 $ 377.9 $ 1,184.8 $ 1,013.4 Lasers 43.5 55.0 125.7 147.3 Net revenue $ 402.8 $ 432.9 $ 1,310.5 $ 1,160.7 Gross profit: OpComms $ 161.8 $ 143.5 $ 550.1 $ 397.5 Lasers 21.6 25.3 56.2 63.6 Total segment gross profit 183.4 168.8 606.3 461.1 Unallocated corporate items: Stock-based compensation (4.3 ) (3.2 ) (12.6 ) (11.7 ) Amortization of acquired intangibles (13.9 ) (28.1 ) (38.8 ) (33.3 ) Amortization of fair value adjustments (1.5 ) (14.5 ) (5.8 ) (15.8 ) Inventory and fixed asset write down due to product lines exit (2.3 ) (19.4 ) (6.0 ) (19.4 ) Integration related costs 0.3 (2.8 ) (3.1 ) (2.8 ) Other charges (1) (4.0 ) (12.5 ) (25.5 ) (39.0 ) Gross profit $ 157.7 $ 88.3 $ 514.5 $ 339.1 (1) “Other charges” of unallocated corporate items for the three and nine months ended March 28, 2020 primarily include costs of transferring product lines to new production facilities, including Thailand of $0.4 million and $8.5 million , respectively. We also incurred excess and obsolete inventory charges driven by the decline in demand from Huawei of $0.1 million and $12.8 million during the three and nine months ended March 28, 2020 . In addition, there were expenses of $1.6 million related to COVID-19 outbreak during the three and nine months ended March 28, 2020 , which include incremental costs for payroll expense such as overtime pay, facilities costs such as gloves, masks and temperature gauges, and under-utilized capacity at certain facilities, in which manufacturing output was impacted. These COVID-19 related costs are offset by benefits realized from government credits for employers’ payroll tax.
Schedule of concentration risks	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 Telecom and Datacom, and Consumer and Industrial markets which accounted for 10% or more of our total net revenue during the periods presented ( in millions, except percentage data ): Three Months Ended Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 OpComms: Telecom and Datacom $ 251.0 62.3 % $ 300.7 69.5 % $ 765.4 58.4 % $ 683.7 58.9 % Consumer and Industrial 108.3 26.9 77.2 17.8 419.4 32.0 329.7 28.4 Total OpComms $ 359.3 89.2 % $ 377.9 87.3 % $ 1,184.8 90.4 % $ 1,013.4 87.3 % Lasers 43.5 10.8 55.0 12.7 125.7 9.6 147.3 12.7 Total Revenue $ 402.8 $ 432.9 $ 1,310.5 $ 1,160.7
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 Nine Months Ended March 28, 2020 March 30, 2019 March 28, 2020 March 30, 2019 Amount % of Total Amount % of Total Amount % of Total Amount % of Total Americas: United States $ 38.6 9.6 % $ 29.7 6.9 % $ 118.9 9.1 % $ 72.3 6.3 % Mexico 33.2 8.2 53.5 12.3 88.3 6.7 164.8 14.2 Other Americas 1.4 0.3 0.9 0.2 3.2 0.3 2.7 0.2 Total Americas $ 73.2 18.1 % $ 84.1 19.4 % $ 210.4 16.1 % $ 239.8 20.7 % Asia-Pacific: Hong Kong $ 125.9 31.3 % $ 124.1 28.6 % $ 404.2 30.8 % $ 289.6 25.0 % South Korea 63.3 15.7 23.6 5.5 239.9 18.3 154.9 13.3 Japan 35.8 8.9 50.0 11.6 110.4 8.4 129.2 11.1 Other Asia-Pacific 77.2 19.2 98.4 22.7 248.8 19.0 234.4 20.2 Total Asia-Pacific $ 302.2 75.1 % $ 296.1 68.4 % $ 1,003.3 76.5 % $ 808.1 69.6 % EMEA $ 27.4 6.8 % $ 52.7 12.2 % $ 96.8 7.4 % $ 112.8 9.7 % Total net revenue $ 402.8 $ 432.9 $ 1,310.5 $ 1,160.7
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 as of March 28, 2020 ( in millions ): Less than 1 year 1-2 years Greater than 2 years Total Performance obligations $513.9 $32.7 $— $546.6
Schedule of changes in contract balances	The following table reflects the changes in contract balances as of March 28, 2020 ( in millions, except percentages ): Contract balances Balance sheet location March 28, 2020 June 29, 2019 Change Percentage Change Accounts receivable, net Accounts receivable, net $261.8 $238.0 $23.8 10.0% Deferred revenue and customer deposits Other current liabilities $1.7 $2.9 $(1.2) (41.4)%
Schedule of long-lived assets by geographic region	Long-lived assets, namely net property, plant and equipment, net, were identified based on the physical location of the assets in the corresponding geographic areas as of the periods indicated (in millions) : March 28, 2020 June 29, 2019 Property, plant and equipment, net United States $ 145.8 $ 156.2 Thailand 135.3 157.1 China 43.3 33.5 Japan 29.2 28.3 Other countries 56.5 58.2 Total long-lived assets $ 410.1 $ 433.3

Recently Issued Accounting Pr_2

Recently Issued Accounting Pronouncements - Narrative (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 30, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net	$ 81.7
Operating lease liabilities	70.6
Finance lease liabilities	$ 4
Topic 842
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets, net		$ 91.5
Operating lease liabilities		81.5
Finance lease assets		12.4
Finance lease liabilities		$ 12.4

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						9 Months Ended
	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Mar. 28, 2020	Mar. 30, 2019
Basic Earnings per Common Share
Net income (loss)	$ 43.4	$ 49.1	$ 47.6	$ (74.3)	$ 16.3	$ 47.4	$ 140.1	$ (10.6)
Less: Cumulative dividends on Series A Preferred Stock	0			0			0	(0.3)
Less: Earnings allocated to Series A Preferred Stock	0			0			0	(1.2)
Net income (loss) attributable to common stockholders - Basic	$ 43.4			$ (74.3)			$ 140.1	$ (12.1)
Weighted average common shares outstanding including Series A Preferred Stock (in shares)	74.8			76.2			76.2	69.4
Less: Weighted average Series A Preferred Stock (in shares)	0			0			0	(0.7)
Weighted average common shares outstanding for basic earnings per common share (in shares)	74.8			76.2			76.2	68.7
Net income per share attributable to common stockholders - Basic (in dollars per share)	$ 0.58			$ (0.98)			$ 1.84	$ (0.18)
Diluted Earnings per Common Share
Net income (loss) attributable to common stockholders - Basic	$ 43.4			$ (74.3)			$ 140.1	$ (12.1)
Net income (loss) attributable to common stockholders - Diluted	$ 43.4			$ (74.3)			$ 140.1	$ (12.1)
Weighted average common shares outstanding for basic earnings per common share (in shares)	74.8			76.2			76.2	68.7
Effect of dilutive securities from 2015 Equity Incentive Plan (in shares)	1			0			0.8	0
Shares issuable assuming conversion of the 2024 Notes (in shares)	1.7			0			0.7	0
Diluted weighted average common shares outstanding (in shares)	77.5			76.2			77.7	68.7
Net income per share attributable to common stockholders - Diluted (in dollars per share)	$ 0.56			$ (0.98)			$ 1.80	$ (0.18)

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - USD ($)	Nov. 02, 2018	Mar. 30, 2019	Mar. 30, 2019	Mar. 28, 2020	Dec. 12, 2019	Jun. 29, 2019	Mar. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)		700,000	600,000
Convertible Debt | 2024 Notes
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 (in dollars per share)				$ 60.62			$ 60.62
Convertible Debt | 2026 Notes
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Debt, aggregate principal amount				$ 1,050,000,000	$ 1,050,000,000
Debt, stated interest rate				0.50%	0.50%
Conversion price (in dollars per share)				$ 99.29	$ 99.29
Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issued upon conversion of series a preferred stock (in shares)	1,500,000
Viavi | Amada | Convertible Series A Preferred Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of shares sold (in shares)	35,805

Business Combinations - Conside

Business Combinations - Consideration Transferred (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 10, 2018	Mar. 28, 2020	Mar. 30, 2019
Business Acquisition [Line Items]
Issuance of common stock in connection with Oclaro acquisition		$ 0	$ 460.1
Oclaro
Business Acquisition [Line Items]
Common stock issued (in shares)	10,941,436
Common stock issued (usd per share)	$ 41.80
Cash paid for outstanding Oclaro common stock	$ 964.8
Issuance of common stock in connection with Oclaro acquisition	457.4
Replacement equity awards for Oclaro equity awards	2.7
Total consideration	$ 1,424.9

Business Combinations - Narrati

Business Combinations - Narrative (Details) - Disposal group, not discontinued operations - Product lines in Datacom business $ in Millions	Apr. 18, 2019USD ($)
Business Acquisition [Line Items]
Sale of product lines	$ 25.5
Assets	33.5
Liabilities	$ 7

Business Combinations - Assets

Business Combinations - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Business Acquisition [Line Items]
Goodwill	$ 368.9	$ 368.9
Oclaro
Business Acquisition [Line Items]
Cash and cash equivalents		345
Accounts receivable, net		68
Inventories		155
Prepayments and other current assets		33.7
Property, plant and equipment, net		134.7
Intangibles		444
Deferred income tax asset		42.6
Other non-current assets		16.6
Accounts payable		(57.8)
Accrued payroll and related expenses		(11.4)
Accrued expenses		(8.3)
Other current liabilities		(6.1)
Deferred tax liability		(75.8)
Other non-current liabilities		(12.9)
Goodwill		357.6
Total purchase price		$ 1,424.9

Business Combinations - Pro For

Business Combinations - Pro Forma Information (Details) - Oclaro $ in Millions	9 Months Ended
	Mar. 28, 2020USD ($)
Business Acquisition [Line Items]
Net revenue	$ 1,374.8
Net loss	$ (18.2)

Assets and Liabilities Held F_2

Assets and Liabilities Held For Sale (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 28, 2020	Jun. 29, 2019
Lithium Niobate
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposal group	$ 6.6
Liabilities of disposal group	3.5
Gain on disposal	13.8
Lithium Niobate | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of product lines	17
Proceeds from sale of product lines	16.9
Remaining holdback	0.1
Datacom | Disposed of by Sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale of product lines	2
Impairment of assets to be disposed of	1.6
Datacom | Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property, plant and equipment, net	$ 1.3	$ 4.9

Cash, Cash Equivalents and Sh_3

Cash, Cash Equivalents and Short-term Investments - Summary of Cash, Cash Equivalents and Short-term Investments (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019	Mar. 30, 2019
Cash and cash equivalents:
Cash and cash equivalents	$ 688.3	$ 432.6	$ 358.3
Cash and cash equivalents, amortized cost	688.2
Cash and cash equivalents, gross unrealized gains	0.1
Short-term investments:
Amortized Cost	763.4	334.8
Gross Unrealized Gains	2.2	1.2
Gross Unrealized Losses	(2.5)	(0.1)
Fair Value	763.1	335.9
Certificates of deposit
Short-term investments:
Amortized Cost	4.4	1.9
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	4.4	1.9
Commercial paper
Short-term investments:
Amortized Cost	88.1	22.3
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	88.1	22.3
Asset-backed securities
Short-term investments:
Amortized Cost		54.9
Gross Unrealized Gains		0.2
Gross Unrealized Losses		0
Fair Value		55.1
Corporate debt securities
Short-term investments:
Amortized Cost	343.2	207.6
Gross Unrealized Gains	0.2	0.9
Gross Unrealized Losses	(2.5)	(0.1)
Fair Value	340.9	208.4
Municipal bonds
Short-term investments:
Amortized Cost		1.3
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		1.3
Mortgage-backed securities
Short-term investments:
Amortized Cost		6.6
Gross Unrealized Gains		0
Gross Unrealized Losses		0
Fair Value		6.6
Foreign government bonds
Short-term investments:
Amortized Cost	4	6.2
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	4	6.2
U.S. Agency securities
Short-term investments:
Amortized Cost	23	4.6
Gross Unrealized Gains	0.1	0
Gross Unrealized Losses	0	0
Fair Value	23.1	4.6
U.S. Treasury securities
Short-term investments:
Amortized Cost	300.7	29.4
Gross Unrealized Gains	1.9	0.1
Gross Unrealized Losses	0	0
Fair Value	302.6	29.5
Cash
Cash and cash equivalents:
Cash and cash equivalents	121.3	213.8
Commercial paper
Cash and cash equivalents:
Cash and cash equivalents	72.6	37.4
Corporate debt securities
Cash and cash equivalents:
Cash and cash equivalents	3
Money market funds
Cash and cash equivalents:
Cash and cash equivalents	426.2	168.1
U.S. Treasury securities
Cash and cash equivalents:
Cash and cash equivalents	65.2	$ 13.3
Cash and cash equivalents, amortized cost	65.1
Cash and cash equivalents, gross unrealized gains	$ 0.1

Cash, Cash Equivalents and Sh_4

Cash, Cash Equivalents and Short-term Investments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Other income (expense), net	$ 21.7	$ 5.2	$ 27.9	$ 11.7
Income on short-term investments and cash equivalents	$ 5.2	$ 3.9	$ 12.6	$ 10

Cash, Cash Equivalents and Sh_5

Cash, Cash Equivalents and Short-term Investments - Summary of Unrealized Losses (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months	$ 366.8	$ 20.7
Fair Value, 12 Months or Greater	0	43.9
Fair Value, Total	366.8	64.6
Unrealized Losses
Unrealized Losses, Less than 12 months	(2.5)	0
Unrealized Losses, 12 Months or Greater	0	(0.1)
Unrealized Losses, Total	(2.5)	(0.1)
U.S. Agency securities
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months	8
Fair Value, 12 Months or Greater	0
Fair Value, Total	8
Unrealized Losses
Unrealized Losses, Less than 12 months	0
Unrealized Losses, 12 Months or Greater	0
Unrealized Losses, Total	0
Certificates of deposit
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months	2.5
Fair Value, 12 Months or Greater	0
Fair Value, Total	2.5
Unrealized Losses
Unrealized Losses, Less than 12 months	0
Unrealized Losses, 12 Months or Greater	0
Unrealized Losses, Total	0
Commercial paper
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months	55.2
Fair Value, 12 Months or Greater	0
Fair Value, Total	55.2
Unrealized Losses
Unrealized Losses, Less than 12 months	0
Unrealized Losses, 12 Months or Greater	0
Unrealized Losses, Total	0
Asset-backed securities
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months		4.2
Fair Value, 12 Months or Greater		5.9
Fair Value, Total		10.1
Unrealized Losses
Unrealized Losses, Less than 12 months		0
Unrealized Losses, 12 Months or Greater		0
Unrealized Losses, Total		0
Corporate debt securities
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months	301.1	9.6
Fair Value, 12 Months or Greater	0	35.9
Fair Value, Total	301.1	45.5
Unrealized Losses
Unrealized Losses, Less than 12 months	(2.5)	0
Unrealized Losses, 12 Months or Greater	0	(0.1)
Unrealized Losses, Total	$ (2.5)	(0.1)
Foreign government bonds
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months		0
Fair Value, 12 Months or Greater		2.1
Fair Value, Total		2.1
Unrealized Losses
Unrealized Losses, Less than 12 months		0
Unrealized Losses, 12 Months or Greater		0
Unrealized Losses, Total		0
U.S. government bonds
Cash and Cash Equivalents [Line Items]
Fair Value, Less than 12 months		6.9
Fair Value, 12 Months or Greater		0
Fair Value, Total		6.9
Unrealized Losses
Unrealized Losses, Less than 12 months		0
Unrealized Losses, 12 Months or Greater		0
Unrealized Losses, Total		$ 0

Cash, Cash Equivalents and Sh_6

Cash, Cash Equivalents and Short-term Investments - Investments in Debt Securities by Contractual Maturities (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Amortized Cost
Due in 1 year	$ 720.1	$ 178.9
Due in 1 year through 5 years	43.3	148.1
Due in 5 years through 10 years	0	6
Due after 10 years	0	1.8
Total	763.4	334.8
Fair Value
Due in 1 year	720	179.1
Due in 1 year through 5 years	43.1	149
Due in 5 years through 10 years	0	6
Due after 10 years	0	1.8
Total	$ 763.1	$ 335.9

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - Convertible Debt - USD ($) $ in Millions	Mar. 28, 2020	Dec. 12, 2019
2026 Notes
Business Acquisition [Line Items]
Convertible senior notes fair value		$ 734.8
2026 Notes | Level 2
Business Acquisition [Line Items]
Convertible senior notes fair value	$ 1,000
2024 Notes | Level 2
Business Acquisition [Line Items]
Convertible senior notes fair value	$ 581

Fair Value Measurements - Measu

Fair Value Measurements - Measured on a Recurring Basis (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019	Mar. 30, 2019
Assets:
Short-term investments	$ 763.1	$ 335.9
Other current liabilities:
Cash held in bank	688.3	432.6	$ 358.3
Certificates of deposit
Assets:
Short-term investments	4.4	1.9
Commercial paper
Assets:
Short-term investments	88.1	22.3
Asset-backed securities
Assets:
Short-term investments		55.1
Corporate debt securities
Assets:
Short-term investments	340.9	208.4
Municipal bonds
Assets:
Short-term investments		1.3
Mortgage-backed securities
Assets:
Short-term investments		6.6
Foreign government bonds
Assets:
Short-term investments	4	6.2
U.S. Agency securities
Assets:
Short-term investments	23.1	4.6
U.S. Treasury securities
Assets:
Short-term investments	302.6	29.5
Commercial paper
Other current liabilities:
Cash held in bank	72.6	37.4
Corporate debt securities
Other current liabilities:
Cash held in bank	3
Money market funds
Other current liabilities:
Cash held in bank	426.2	168.1
U.S. Treasury securities
Other current liabilities:
Cash held in bank	65.2	13.3
Cash
Other current liabilities:
Cash held in bank	121.3	213.8
Recurring basis
Assets:
Total assets	1,330.1	554.7
Other current liabilities:
Acquisition contingency		2.7
Total other accrued liabilities		2.7
Recurring basis | Certificates of deposit
Assets:
Short-term investments	4.4	1.9
Recurring basis | Commercial paper
Assets:
Short-term investments	88.1	22.3
Recurring basis | Asset-backed securities
Assets:
Short-term investments		55.1
Recurring basis | Corporate debt securities
Assets:
Short-term investments	340.9	208.4
Recurring basis | Municipal bonds
Assets:
Short-term investments		1.3
Recurring basis | Mortgage-backed securities
Assets:
Short-term investments		6.6
Recurring basis | Foreign government bonds
Assets:
Short-term investments	4	6.2
Recurring basis | U.S. Agency securities
Assets:
Short-term investments	23.1	4.6
Recurring basis | U.S. Treasury securities
Assets:
Short-term investments	302.6	29.5
Recurring basis | Commercial paper
Assets:
Cash equivalents	72.6	37.4
Recurring basis | Corporate debt securities
Assets:
Cash equivalents	3
Recurring basis | Money market funds
Assets:
Cash equivalents	426.2	168.1
Recurring basis | U.S. Treasury securities
Assets:
Cash equivalents	65.2	13.3
Recurring basis | Level 1
Assets:
Total assets	794	210.9
Other current liabilities:
Acquisition contingency		0
Total other accrued liabilities		0
Recurring basis | Level 1 | Certificates of deposit
Assets:
Short-term investments	0	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
Recurring basis | Level 1 | Corporate debt securities
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | Municipal bonds
Assets:
Short-term investments		0
Recurring basis | Level 1 | Mortgage-backed securities
Assets:
Short-term investments		0
Recurring basis | Level 1 | Foreign government bonds
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | U.S. Agency securities
Assets:
Short-term investments	0	0
Recurring basis | Level 1 | U.S. Treasury securities
Assets:
Short-term investments	302.6	29.5
Recurring basis | Level 1 | Commercial paper
Assets:
Cash equivalents	0	0
Recurring basis | Level 1 | Corporate debt securities
Assets:
Cash equivalents	0
Recurring basis | Level 1 | Money market funds
Assets:
Cash equivalents	426.2	168.1
Recurring basis | Level 1 | U.S. Treasury securities
Assets:
Cash equivalents	65.2	13.3
Recurring basis | Level 2
Assets:
Total assets	536.1	343.8
Other current liabilities:
Acquisition contingency		0
Total other accrued liabilities		0
Recurring basis | Level 2 | Certificates of deposit
Assets:
Short-term investments		1.9
Recurring basis | Level 2 | Commercial paper
Assets:
Short-term investments	88.1	22.3
Recurring basis | Level 2 | Asset-backed securities
Assets:
Short-term investments		55.1
Recurring basis | Level 2 | Corporate debt securities
Assets:
Short-term investments	340.9	208.4
Recurring basis | Level 2 | Municipal bonds
Assets:
Short-term investments		1.3
Recurring basis | Level 2 | Mortgage-backed securities
Assets:
Short-term investments		6.6
Recurring basis | Level 2 | Foreign government bonds
Assets:
Short-term investments	4	6.2
Recurring basis | Level 2 | U.S. Agency securities
Assets:
Short-term investments	23.1	4.6
Recurring basis | Level 2 | U.S. Treasury securities
Assets:
Short-term investments	0	0
Recurring basis | Level 2 | Commercial paper
Assets:
Cash equivalents	72.6	37.4
Recurring basis | Level 2 | Corporate debt securities
Assets:
Cash equivalents	3
Recurring basis | Level 2 | Money market funds
Assets:
Cash equivalents	0	0
Recurring basis | Level 2 | U.S. Treasury securities
Assets:
Cash equivalents	0	0
Recurring basis | Level 3
Assets:
Total assets	0	0
Other current liabilities:
Acquisition contingency		2.7
Total other accrued liabilities		2.7
Recurring basis | Level 3 | Certificates of deposit
Assets:
Short-term investments	0	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
Recurring basis | Level 3 | Corporate debt securities
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Municipal bonds
Assets:
Short-term investments		0
Recurring basis | Level 3 | Mortgage-backed securities
Assets:
Short-term investments		0
Recurring basis | Level 3 | Foreign government bonds
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | U.S. Agency securities
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | U.S. Treasury securities
Assets:
Short-term investments	0	0
Recurring basis | Level 3 | Commercial paper
Assets:
Cash equivalents	0	0
Recurring basis | Level 3 | Corporate debt securities
Assets:
Cash equivalents	0
Recurring basis | Level 3 | Money market funds
Assets:
Cash equivalents	0	0
Recurring basis | Level 3 | U.S. Treasury securities
Assets:
Cash equivalents	$ 0	$ 0

Balance Sheet Details - Account

Balance Sheet Details - Accounts Receivable Allowances (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Accounts receivable allowance	$ 1.7	$ 4.5

Balance Sheet Details - Invento

Balance Sheet Details - Inventories (Details) - USD ($) $ in Millions	9 Months Ended		12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Jun. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Raw materials and purchased parts	$ 55.4		$ 78.3
Work in process	67.9		72.5
Finished goods	49.4		78
Inventories	172.7		228.8
Business Acquisition [Line Items]
Inventory step-up adjustment	$ 5.8	$ 15.8
Oclaro
Business Acquisition [Line Items]
Inventory step-up adjustment			$ 5.7

Balance Sheet Details - Prepaym

Balance Sheet Details - Prepayments and Other Current Assets (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Prepayments	$ 29.7	$ 32.4
Vendor receivable	29.8	36.3
Value added tax receivable	11.5	11.9
Advances to contract manufacturers	0	8.7
Assets held-for-sale	1.3	4.9
Other current assets	4.8	3.3
Prepayments and other current assets	$ 77.1	$ 97.5

Balance Sheet Details - Operati

Balance Sheet Details - Operating Lease Right-of-Use Assets (Details) $ in Millions	Mar. 28, 2020USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating lease right-of-use assets	$ 90.3
Less: accumulated amortization	(8.6)
Operating lease right-of-use assets, net	$ 81.7

Balance Sheet Details - Propert

Balance Sheet Details - Property, Plant and Equipment, Net (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019	Jun. 29, 2019
Property, Plant and Equipment [Line Items]
Total property, plant and equipment, gross	$ 812.6		$ 812.6		$ 772.7
Less: Accumulated depreciation	(402.5)		(402.5)		(339.4)
Property, plant and equipment, net	410.1		410.1		433.3
Depreciation expense	27.5	$ 29	87.8	$ 74.7
Purchase price for property			64.9	80.5
Land
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	44.2		44.2		44.2
Purchase price for property					32.9
Buildings and improvement
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	112.9		112.9		103.7
Purchase price for property					21.7
Machinery and equipment
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	514.1		514.1		500.5
Computer equipment and software
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	25.6		25.6		25.4
Furniture and fixtures
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	6.6		6.6		4.9
Leasehold improvements
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	28.1		28.1		31.2
Finance lease right-of-use assets
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross					16
Property, plant and equipment, finance lease, gross	28.1		28.1		16
Less: Accumulated depreciation	(24.2)		(24.2)		(11.2)
Depreciation expense	4.8	$ 1.5	13	$ 4.6
Construction in progress
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 53		$ 53		46.8
Property in California
Property, Plant and Equipment [Line Items]
Purchase price for property					$ 54.6

Balance Sheet Details - Other C

Balance Sheet Details - Other Current Liabilities (Details) - USD ($) $ in Millions	Mar. 28, 2020	Dec. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Jun. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Restructuring accrual and related charges	$ 2.6	$ 5	$ 14.6	$ 18	$ 3.5	$ 1.9
Warranty accrual	5.4		7.5
Deferred revenue and customer deposits	1.7		2.9
Finance lease liabilities, current	3.9		0.4
Income tax payable	30.4		8.7
Other current liabilities	2.8		5.1
Other current liabilities	46.8		$ 39.2
Finance lease liabilities, non-current	$ 0.1

Balance Sheet Details - Other N

Balance Sheet Details - Other Non-Current Liabilities (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Asset retirement obligations	$ 4.9	$ 4.5
Deferred rent		2.2
Unrecognized tax benefit	18.1	18.7
Finance lease liabilities, non-current	0.1
Other non-current liabilities	0.6	0.4
Total other non-current liabilities	33.7	33.7
Defined Benefit Plan Disclosure [Line Items]
Pension and related accrual	10	7.9
Post-Retirement Benefits For Executives
Defined Benefit Plan Disclosure [Line Items]
Pension and related accrual		0.1
Japan
Defined Benefit Plan Disclosure [Line Items]
Pension and related accrual	2.8	2.8
SWITZERLAND
Defined Benefit Plan Disclosure [Line Items]
Pension and related accrual	4.7	$ 5
Thailand
Defined Benefit Plan Disclosure [Line Items]
Pension and related accrual	$ 2.5

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 28, 2020	Mar. 28, 2020	Jul. 01, 2023
Lessor, Lease, Description [Line Items]
Sublease income	$ 0.7	$ 1.9
Sublease income, term		3 years
Forecast | United Kingdom, Canada, and Japan
Lessor, Lease, Description [Line Items]
Sublease income			$ 5.9
Minimum
Lessor, Lease, Description [Line Items]
Finance lease term	2 years	2 years
Maximum
Lessor, Lease, Description [Line Items]
Finance lease term	4 years	4 years

Leases - Lease Costs, Term, and

Leases - Lease Costs, Term, and Discount Rate (Details) $ in Millions	3 Months Ended	9 Months Ended
	Mar. 28, 2020USD ($)	Mar. 28, 2020USD ($)
Leases [Abstract]
Finance lease cost, Amortization of right-of-use assets	$ 4.8	$ 13
Finance lease cost, Interest	0	0.1
Operating lease cost	3.9	11.9
Variable lease cost	0.4	1.5
Short-term lease cost	0.7	1.7
Sublease income	(0.7)	(1.9)
Total lease cost	$ 9.1	$ 26.3
Weighted average remaining lease term, Operating leases	8 years 10 months 24 days	8 years 10 months 24 days
Weighted average remaining lease term, Finance leases	21 days	21 days
Weighted average discount rate, Operating leases	3.65%	3.65%
Weighted average discount rate, Finance leases	4.38%	4.38%

Leases - Lease Maturities (Deta

Leases - Lease Maturities (Details) $ in Millions	Mar. 28, 2020USD ($)
Operating Leases
Remainder of 2020	$ 3.3
2021	13.1
2022	12.3
2023	11.1
2024	9.4
Thereafter	31.4
Total minimum lease payments	80.6
Less: amount representing interest	(10)
Present value of total lease liabilities	70.6
Finance Leases
Remainder of 2020	3.4
2021	0.6
2022	0
2023	0
2024	0
Thereafter	0
Total minimum lease payments	4
Less: amount representing interest	0
Present value of total lease liabilities	4
Total
Remainder of 2020	6.7
2021	13.7
2022	12.3
2023	11.1
2024	9.4
Thereafter	31.4
Total minimum lease payments	84.6
Less: amount representing interest	(10)
Present value of total lease liabilities	74.6
Sublease Proceeds
Remainder of 2020	0.7
2021	2.4
2022	2.2
2023	$ 0.6

Leases - Lease Maturities Prior

Leases - Lease Maturities Prior to Adoption (Details) $ in Millions	Jun. 29, 2019USD ($)
Operating Leases
2020	$ 13.9
2021	12.1
2022	11.2
2023	11.3
2024	9.8
Thereafter	31.7
Total minimum operating lease payments	90
Finance Leases
2020	0.8
2021	0
2022	0
2023	0
2024	0
Thereafter	0
Total minimum operating lease payments	0.8
Total
2020	14.7
2021	12.1
2022	11.2
2023	11.3
2024	9.8
Thereafter	31.7
Total minimum operating lease payments	$ 90.8

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets - Narrative (Details) - USD ($)	Dec. 10, 2018	Mar. 28, 2020	Jun. 29, 2019	Mar. 28, 2020	Jun. 29, 2019
Business Acquisition [Line Items]
Goodwill		$ 368,900,000	$ 368,900,000	$ 368,900,000	$ 368,900,000
Goodwill impairment			0
In-process research and development
Business Acquisition [Line Items]
Intangible assets preliminary estimate		$ 7,000,000		59,000,000
In-process research and development | Minimum
Business Acquisition [Line Items]
Useful life		4 years
In-process research and development | Maximum
Business Acquisition [Line Items]
Useful life		5 years
In-process research and development | Disposal group, not discontinued operations | Product lines in Datacom business
Business Acquisition [Line Items]
Intangible assets preliminary estimate					1,000,000
Oclaro
Business Acquisition [Line Items]
Goodwill			$ 357,600,000		357,600,000
Intangible assets preliminary estimate					$ 443,000,000
Oclaro | In-process research and development | Minimum
Business Acquisition [Line Items]
Useful life	4 years
Oclaro | In-process research and development | Maximum
Business Acquisition [Line Items]
Useful life	9 years
OpComms
Business Acquisition [Line Items]
Goodwill		$ 363,500,000		$ 363,500,000
OpComms | Oclaro
Business Acquisition [Line Items]
Goodwill	$ 357,600,000

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Schedule of Changes in Goodwill (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Changes in goodwill
Goodwill	$ 368.9	$ 368.9
Optical Communications
Changes in goodwill
Goodwill	363.5
Commercial Lasers
Changes in goodwill
Goodwill	$ 5.4

Goodwill and Other Intangible_5

Goodwill and Other Intangible Assets - Acquired Developed Technology and Other Intangibles (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Mar. 28, 2020	Mar. 28, 2020	Jun. 29, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	$ 555.5	$ 555.5	$ 555.5
Accumulated Amortization	(217.5)	(217.5)	(160.1)
Net Carrying Amounts	338	338	395.4
Acquired developed technologies
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	346.5	346.5	287.5
Accumulated Amortization	(161.9)	(161.9)	(125.2)
Net Carrying Amounts	184.6	$ 184.6	$ 162.3
Weighted average remaining amortization period (years)		3 years 6 months	3 years 9 months 18 days
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	149.3	$ 149.3	$ 149.3
Accumulated Amortization	(30.9)	(30.9)	(12.3)
Net Carrying Amounts	118.4	$ 118.4	$ 137
Weighted average remaining amortization period (years)		6 years 8 months 12 days	7 years 6 months
In-process research and development
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	35	$ 35	$ 94
Accumulated Amortization	0	0	0
Net Carrying Amounts	35	35	94
Intangible assets preliminary estimate	$ 7	59
In-process research and development | Minimum
Finite-Lived Intangible Assets [Line Items]
Useful life	4 years
In-process research and development | Maximum
Finite-Lived Intangible Assets [Line Items]
Useful life	5 years
Order backlog
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	$ 22	22	22
Accumulated Amortization	(22)	(22)	(19.9)
Net Carrying Amounts	0	0	$ 2.1
Weighted average remaining amortization period (years)			15 days
Other intangibles
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amounts	2.7	2.7	$ 2.7
Accumulated Amortization	(2.7)	(2.7)	(2.7)
Net Carrying Amounts	$ 0	$ 0	$ 0

Goodwill and Other Intangible_6

Goodwill and Other Intangible Assets - Details of Amortization Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 20	$ 31.7	$ 57.4	$ 37.7
Cost of sales
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	13.9	28.1	38.8	33.3
Selling, general and administrative
Finite-Lived Intangible Assets [Line Items]
Amortization of intangibles	$ 6.1	$ 3.6	$ 18.6	$ 4.4

Goodwill and Other Intangible_7

Goodwill and Other Intangible Assets - Estimated Future Amortization Expense (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Fiscal Years
Net Carrying Amounts	$ 338	$ 395.4
Intangibles excluding in-process research and development
Fiscal Years
Remainder of 2020	20.3
2021	78.9
2022	76.4
2023	52.9
2024	33.1
Thereafter	41.4
Net Carrying Amounts	$ 303

Non-Controlling Interest Rede_2

Non-Controlling Interest Redeemable Convertible Preferred Stock and Derivative Liability (Details) $ in Millions	Nov. 02, 2018USD ($)shares	Oct. 15, 2018	Jul. 31, 2015shares	Mar. 28, 2020USD ($)	Mar. 30, 2019USD ($)	Dec. 29, 2018USD ($)shares	Sep. 29, 2018USD ($)	Mar. 28, 2020USD ($)	Mar. 30, 2019USD ($)	Jun. 29, 2019USD ($)	Jun. 30, 2018USD ($)
Redeemable Noncontrolling Interest [Line Items]
Redemption notice period		30 days
Conversion price denominator before accrued and unpaid dividends		24.63
Conversion of preferred stock to common stock						$ 79.4
Dividends paid for preferred stock						$ 0.1	$ 0.2
Unrealized gain (loss) on derivative liability				$ 0	$ 0			$ 0	$ 8.8
Level 3 | Series A Preferred Stock | Embedded Derivative Liability
Redeemable Noncontrolling Interest [Line Items]
Unrealized gain (loss) on derivative liability									8.8
Common Stock
Redeemable Noncontrolling Interest [Line Items]
Shares issued upon conversion of Series A Preferred Stock | shares	1,500,000					1,500,000
Additional Paid-In Capital
Redeemable Noncontrolling Interest [Line Items]
Conversion of preferred stock to common stock	$ 79.4					$ 79.4		$ 79.4		$ 79.4
Non-Controlling Interest Redeemable Convertible Series A Preferred Stock
Redeemable Noncontrolling Interest [Line Items]
Redemption value					$ 0	$ 0	$ 35.8		$ 0		$ 35.8
Annual dividend rate								2.50%
Accrued dividends	$ 0.3
Non-Controlling Interest Redeemable Convertible Series A Preferred Stock | Viavi
Redeemable Noncontrolling Interest [Line Items]
Number of shares sold (in shares) | shares			40,000
Non-Controlling Interest 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
Series A Preferred Stock
Redeemable Noncontrolling Interest [Line Items]
Dividends paid for preferred stock				$ 0.4

Debt - Convertible Notes Narrat

Debt - Convertible Notes Narrative (Details)	Dec. 12, 2019USD ($)trading_day$ / shares	Mar. 31, 2017USD ($)trading_day$ / shares	Mar. 28, 2020USD ($)$ / shares	Mar. 30, 2019USD ($)	Dec. 28, 2019USD ($)	Jun. 29, 2019USD ($)	Mar. 08, 2017USD ($)
Debt Instrument [Line Items]
Repurchase of common stock			$ 200,000,000	$ 0
Convertible Debt | 2026 Notes
Debt Instrument [Line Items]
Debt, aggregate principal amount	$ 1,050,000,000		$ 1,050,000,000
Repayments of debt	196,000,000
Repurchase of common stock	$ 200,000,000
Debt, stated interest rate	0.50%		0.50%
Conversion rate	0.0100711
Conversion price (in dollars per share) | $ / shares	$ 99.29		$ 99.29
Conversion threshold trading days | trading_day	20
Conversion threshold consecutive trading days | trading_day	30
Conversion threshold percentage of stock price trigger	130.00%
Conversion threshold measurement period	5 days
Percentage of principal amount required to be paid upon contingent note repurchase	100.00%
Liability component	$ 734,800,000
Percentage of equity component	5.80%
Discount	$ 315,200,000		$ 309,800,000
Effective interest rate on the liability component	5.80%
Conversion threshold percentage of conversion rate from measurement period	98.00%
Unamortized value of the debt issuance costs	$ 7,800,000				$ 2,300,000
Convertible Debt | 2024 Notes
Debt Instrument [Line Items]
Debt, aggregate principal amount		$ 450,000,000	$ 450,000,000			$ 450,000,000
Debt, stated interest rate		0.25%	0.25%
Conversion rate		0.0164965
Conversion price (in dollars per share) | $ / shares		$ 60.62	$ 60.62
Conversion threshold trading days | trading_day		20
Conversion threshold consecutive trading days | trading_day		30
Conversion threshold percentage of stock price trigger		130.00%
Conversion threshold measurement period		5 days
Percentage of principal amount required to be paid upon contingent note repurchase		100.00%
Discount			$ 84,200,000			$ 98,100,000
Effective interest rate on the liability component		5.40%
Conversion price premium percentage		132.50%
Sale price of common stock (usd per share) | $ / shares		$ 78.80
Conversion threshold percentage of conversion rate from measurement period		98.00%
Derivative liability fair value							$ 129,900,000
Residual principal amount of notes before issuance costs		$ 320,100,000
Unamortized value of the debt issuance costs		$ 7,700,000

Debt - Components of Convertibl

Debt - Components of Convertible Notes (Details) - Convertible Debt - USD ($)	Mar. 28, 2020	Dec. 12, 2019	Jun. 29, 2019	Mar. 31, 2017
2024 Notes
Liability component:
Principal	$ 450,000,000		$ 450,000,000	$ 450,000,000
Unamortized debt discount	(84,200,000)		(98,100,000)
Total	365,800,000		$ 351,900,000
2026 Notes
Liability component:
Principal	1,050,000,000	$ 1,050,000,000
Unamortized debt discount	(309,800,000)	$ (315,200,000)
Total	$ 740,200,000

Debt - Interest Expense Related

Debt - Interest Expense Related to 2024 Notes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Debt Instrument [Line Items]
Amortization of the debt discount and debt issuance costs			$ 25.3	$ 13.6
Convertible Debt | 2024 Notes
Debt Instrument [Line Items]
Contractual interest expense	$ 1.6	$ 0.3	2.3	0.9
Amortization of the debt discount and debt issuance costs	14	4.5	24.8	13.2
Total interest expense	$ 15.6	$ 4.8	$ 27.1	$ 14.1

Debt - Future Interest and Pri

Debt - Future Interest and Principal Payments (Details) $ in Millions	Mar. 28, 2020USD ($)
Debt Instrument [Line Items]
Remainder of 2020	$ 2.7
2021	6.3
2022	6.4
2023	6.3
2024	456.5
Thereafter	1,063.1
Total	1,541.3
Convertible Debt | 2024 Notes
Debt Instrument [Line Items]
Remainder of 2020	0
2021	1.1
2022	1.1
2023	1.1
2024	451.2
Thereafter	0
Total	454.5
Convertible Debt | 2026 Notes
Debt Instrument [Line Items]
Remainder of 2020	2.7
2021	5.2
2022	5.3
2023	5.2
2024	5.3
Thereafter	1,063.1
Total	$ 1,086.8

Debt - Term Loan Facility Narra

Debt - Term Loan Facility Narrative (Details) - USD ($)	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019	Jun. 29, 2019	Dec. 10, 2018
Debt Instrument [Line Items]
Loss on early extinguishment of debt			$ 8,000,000	$ 0
Finance lease cost, Interest	$ 0		100,000
Secured debt | Term loan
Debt Instrument [Line Items]
Principal	497,500,000		497,500,000		$ 500,000,000	$ 500,000,000
Debt issuance costs					$ 9,300,000
Loss on early extinguishment of debt	$ 0	$ 0	$ 8,000,000	$ 0

Debt - Term Loan Facility Inter

Debt - Term Loan Facility Interest Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Debt Instrument [Line Items]
Loss on early extinguishment of debt			$ 8	$ 0
Total interest expense	$ 15.6	$ 11.3	45.3	24.9
Secured debt | Term loan
Debt Instrument [Line Items]
Contractual interest expense	0	6.2	9.6	10.2
Amortization of the debt issuance costs	0	0.4	0.5	0.5
Loss on early extinguishment of debt	0	0	8	0
Total interest expense	$ 0	$ 6.6	$ 18.1	$ 10.7

Debt - Term Loan Facility Infor

Debt - Term Loan Facility Information (Details) - USD ($)	Mar. 28, 2020	Jun. 29, 2019	Dec. 10, 2018
Debt Instrument [Line Items]
Total	$ 1,541,300,000
Term loan | Secured debt
Debt Instrument [Line Items]
Principal	497,500,000	$ 500,000,000	$ 500,000,000
Repayment of principal	(497,500,000)	(2,500,000)
Unamortized value of the debt issuance costs	0	(8,500,000)
Total	0	489,000,000
Term loan, current	0	5,000,000
Term loan, non-current	$ 0	$ 484,000,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	3 Months Ended						9 Months Ended
	Mar. 28, 2020	Dec. 28, 2019	Sep. 28, 2019	Mar. 30, 2019	Dec. 29, 2018	Sep. 29, 2018	Mar. 28, 2020	Mar. 30, 2019
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	$ 1,681.6	$ 1,561.3	$ 1,497.1	$ 1,559.7	$ 983.5	$ 926.1	$ 1,497.1	$ 926.1
Other comprehensive income	(1.2)	(0.2)	0.1	1.3	(0.7)	0.5	(1.3)	1.1
Balance at the end of the period	1,734.2	1,681.6	1,561.3		1,559.7	983.5	1,734.2
Unrealized gain on available-for-sale securities, tax							0.2
Foreign currency translation adjustments, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	9.7	9.7	9.7	9.7	10.4	10.3	9.7	10.3
Other comprehensive income	0	0	0	0	(0.7)	0.1
Balance at the end of the period	9.7	9.7	9.7	9.7	9.7	10.4	9.7	9.7
Defined benefit obligations, net of tax
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	(3.5)	(3.5)	(3.5)	(2.4)	(2.3)	(2.3)	(3.5)	(2.3)
Other comprehensive income	0	0	0	0	(0.1)	0
Balance at the end of the period	(3.5)	(3.5)	(3.5)	(2.4)	(2.4)	(2.3)	(3.5)	(2.4)
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	0.8	1	0.9	(1.1)	(1.2)	(1.6)	0.9	(1.6)
Other comprehensive income	(1.2)	(0.2)	0.1	1.3	0.1	0.4
Balance at the end of the period	(0.4)	0.8	1	0.2	(1.1)	(1.2)	(0.4)	0.2
Total
Changes in accumulated other comprehensive income (loss) by component
Balance at the beginning of the period	7	7.2	7.1	6.2	6.9	6.4	7.1	6.4
Other comprehensive income	(1.2)	(0.2)	0.1	1.3	(0.7)	0.5
Balance at the end of the period	$ 5.8	$ 7	$ 7.2	$ 7.5	$ 6.2	$ 6.9	$ 5.8	$ 7.5

Restructuring and Related Cha_3

Restructuring and Related Charges - Summary of Activity of Restructuring and Related Charges (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Summary of Restructuring Activity and Related Charges
Balance as of beginning of period	$ 5	$ 3.5	$ 14.6	$ 1.9
Charges	2.7	21.1	4.9	30.2
Payments	(5.1)	(6.6)	(16.9)	(14.1)
Balance as of end of period	$ 2.6	$ 18	$ 2.6	$ 18

Restructuring and Related Cha_4

Restructuring and Related Charges - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Restructuring and Related Charges
Restructuring and related charges	$ 2.7	$ 21.1	$ 4.9	$ 30.2
Lithium Niobate
Restructuring and Related Charges
Restructuring and related charges		$ 21.1		30.2
Lithium Niobate | Severance charges
Restructuring and Related Charges
Restructuring and related charges				18
Lithium Niobate | Lease restructuring
Restructuring and Related Charges
Restructuring and related charges				$ 1.6

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019	Jun. 29, 2019
Income Tax Disclosure [Abstract]
Provision for (benefit from) income taxes	$ 5.2	$ (8.2)	$ 19.6	$ (1.6)
Discrete tax benefit, uncertain tax positions	4.1
Unrecognized tax benefit	18.1		18.1		$ 18.7
Unrecognized tax benefit that could affect tax rate to decrease over next 12 months	$ 1.2		$ 1.2

Stockholders' Equity - Descript

Stockholders' Equity - Description of Lumentum Stock-Based Benefit Plans Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019	Jun. 27, 2015	Jun. 29, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Shares of common stock available for grant (in shares)	3,600,000		3,600,000			4,700,000
Stock-based compensation	$ 19.2	$ 16	$ 56.1	$ 56.5
Full Value Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Stock options issued and outstanding (in shares)	2,400,000		2,400,000
Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Shares of common stock available for grant (in shares)	3,600,000		3,600,000
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]
Vesting period			3 years
2015 Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Shares of common stock available for grant (in shares)	1,900,000		1,900,000
Discount rate provided under purchase plan (as a percent)					15.00%
Look-back period					6 months
Common stock authorized for issuance under plan (in shares)					3,000,000
Stock-based compensation	$ 0.8	$ 1.1	$ 2.5	$ 2.9

Stockholders' Equity - Stock-Ba

Stockholders' Equity - Stock-Based Compensation Expense (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019	Jun. 29, 2019
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 19.2	$ 16	$ 56.1	$ 56.5
Income tax benefit associated with stock-based compensation	2.4	2.1	9	8.8
Stock-based compensation capitalized to inventory			3		$ 3.5
Cost of sales
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	4.3	3.2	12.6	11.7
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	4.2	4.5	12.1	10.7
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 10.7	$ 8.3	$ 31.4	$ 34.1

Stockholders' Equity - Stock Aw

Stockholders' Equity - Stock Award Activity (Details) shares in Millions	9 Months Ended
	Mar. 28, 2020$ / sharesshares
Restricted Stock Units
Number of Shares
Unvested balance as of beginning of period (in shares) | shares	2.2
Granted (in shares) | shares	1
Vested/Exercised (in shares) | shares	(1)
Canceled (in shares) | shares	(0.2)
Unvested balance as of end of period (in shares) | shares	2
Weighted-Average Grant Date Fair Value per Share
Balance at beginning of period (usd per share) | $ / shares	$ 52.4
Granted (usd per share) | $ / shares	59.3
Vested/Exercised (usd per share) | $ / shares	52.1
Canceled (usd per share) | $ / shares	51.7
Balance at end of period (usd per share) | $ / shares	$ 55.6
Restricted Stock Awards
Number of Shares
Unvested balance as of beginning of period (in shares) | shares	0
Granted (in shares) | shares	0
Vested/Exercised (in shares) | shares	0
Canceled (in shares) | shares	0
Unvested balance as of end of period (in shares) | shares	0
Weighted-Average Grant Date Fair Value per Share
Balance at beginning of period (usd per share) | $ / shares	$ 32.5
Granted (usd per share) | $ / shares	0
Vested/Exercised (usd per share) | $ / shares	32.5
Canceled (usd per share) | $ / shares	0
Balance at end of period (usd per share) | $ / shares	$ 0
Performance Stock Units
Number of Shares
Unvested balance as of beginning of period (in shares) | shares	0.2
Granted (in shares) | shares	0.2
Vested/Exercised (in shares) | shares	(0.1)
Canceled (in shares) | shares	0
Unvested balance as of end of period (in shares) | shares	0.3
Weighted-Average Grant Date Fair Value per Share
Balance at beginning of period (usd per share) | $ / shares	$ 56
Granted (usd per share) | $ / shares	61.9
Vested/Exercised (usd per share) | $ / shares	54.6
Canceled (usd per share) | $ / shares	57.3
Balance at end of period (usd per share) | $ / shares	$ 60.2

Stockholders' Equity - Stock _2

Stockholders' Equity - Stock Award Activity Narrative (Details) $ in Millions	9 Months Ended
	Mar. 28, 2020USD ($)
Share-based Payment Arrangement [Abstract]
Stock-based compensation cost related to awards granted to employees	$ 111.6
Estimated amortization period	1 year 10 months 24 days

Stockholders' Equity - Awards A

Stockholders' Equity - Awards Available for Grant (Details) shares in Millions	9 Months Ended
	Mar. 28, 2020shares
Share-based Payment Arrangement [Abstract]
Balance as of beginning of period (in shares)	4.7
Granted (in shares)	(1.2)
Canceled (in shares)	0.1
Balance as of end of period (in shares)	3.6

Stockholders' Equity - Employee

Stockholders' Equity - Employee Stock Purchase Plan Activity Narrative (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 19.2	$ 16	$ 56.1	$ 56.5
Shares issued to employees (in shares)	100,000		100,000
2015 Purchase Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation	$ 0.8	$ 1.1	$ 2.5	$ 2.9

Stockholders' Equity - Schedule

Stockholders' Equity - Schedule of Assumptions Used to Estimate Fair Value (Details) - 2015 Purchase Plan	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line items]
Expected term	6 months	6 months	15 days	15 days
Expected volatility	44.60%	71.30%	44.60%	71.30%
Risk-free interest rate	1.59%	2.52%	1.59%	2.52%
Dividend yield	0.00%	0.00%	0.00%	0.00%

Stockholders' Equity - Repurcha

Stockholders' Equity - Repurchase and Retirement of Common Stock Narrative (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	1 Months Ended	3 Months Ended
	Dec. 31, 2019	Dec. 28, 2019
Share-based Payment Arrangement [Abstract]
Repurchases of common stock (in shares)	2.9
Average cost per share (in dollars per share)	$ 69.68
Repurchases of common stock	$ 200	$ 200

Commitments and Contingencies -

Commitments and Contingencies - Purchase Obligations Narrative (Details) $ in Millions	9 Months Ended
	Mar. 28, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Legally-binding purchase commitment obligations	$ 257.2
Typical duration of supply agreements with single or limited source vendors	1 year

Commitments and Contingencies_2

Commitments and Contingencies - Product Warranties Narrative (Details)	9 Months Ended
	Mar. 28, 2020
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_3

Commitments and Contingencies - Schedule of Changes in Warranty Reserve (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Changes in warranty reserve
Balance as of beginning of period	$ 6.8	$ 9.7	$ 7.5	$ 6.6
Warranties assumed in Oclaro acquisition	0	0	0	3.8
Provision for warranty	0.7	1.5	2.5	3.4
Utilization of reserve	(2.1)	(1.4)	(4.6)	(4)
Balance as of end of period	$ 5.4	$ 9.8	$ 5.4	$ 9.8

Commitments and Contingencies_4

Commitments and Contingencies - Legal Proceedings (Details) $ in Millions	Mar. 28, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Litigation contingency accrual	$ 1

Commitments and Contingencies_5

Commitments and Contingencies - Merger Litigation (Details)	9 Months Ended
	Mar. 28, 2020lawsuit_filed
Oclaro
Business Acquisition [Line Items]
Number of lawsuits filed	7

Commitments and Contingencies_6

Commitments and Contingencies - Audit Proceedings Narrative (Details) - Oclaro - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 10, 2018
Liability for Claims and Claims Adjustment Expense [Line Items]
Tax refund claims receivable		$ 1.1
Income tax examination initial claim	$ 2.5

Operating Segments and Geogra_3

Operating Segments and Geographic Information - Narrative (Details)	3 Months Ended		9 Months Ended		12 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020regionsegment	Mar. 30, 2019	Jun. 29, 2019
Concentration Risk [Line Items]
Number of operating segments			2
Number of reportable segments			2
Number of geographic regions | region			3
Revenue | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk percentage	37.00%	44.00%	42.00%	52.00%
Revenue | Customer concentration risk | Outside of U.S
Concentration Risk [Line Items]
Concentration risk percentage	90.40%	93.10%	90.90%	93.70%
Accounts Receivable | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk percentage			27.00%		44.00%
Inventory Purchases | Customer concentration risk
Concentration Risk [Line Items]
Concentration risk percentage	88.00%	85.00%	85.00%	85.00%

Operating Segments and Geogra_4

Operating Segments and Geographic Information - Schedule of Information on Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Information on reportable segments
Net revenue	$ 402.8	$ 432.9	$ 1,310.5	$ 1,160.7
Gross profit	157.7	88.3	514.5	339.1
Stock-based compensation	(19.2)	(16)	(56.1)	(56.5)
Amortization of acquired intangibles	(20)	(31.7)	(57.4)	(37.7)
Expenses related to COVID-19 outbreak	1.6		1.6
OpComms
Information on reportable segments
Net revenue	359.3	377.9	1,184.8	1,013.4
Lasers
Information on reportable segments
Net revenue	43.5	55	125.7	147.3
Operating segments
Information on reportable segments
Net revenue	402.8	432.9	1,310.5	1,160.7
Gross profit	183.4	168.8	606.3	461.1
Operating segments | OpComms
Information on reportable segments
Net revenue	359.3	377.9	1,184.8	1,013.4
Gross profit	161.8	143.5	550.1	397.5
Operating segments | Lasers
Information on reportable segments
Net revenue	43.5	55	125.7	147.3
Gross profit	21.6	25.3	56.2	63.6
Unallocated corporate items
Information on reportable segments
Stock-based compensation	(4.3)	(3.2)	(12.6)	(11.7)
Amortization of acquired intangibles	(13.9)	(28.1)	(38.8)	(33.3)
Amortization of fair value adjustments	(1.5)	(14.5)	(5.8)	(15.8)
Inventory and fixed asset write down due to product lines exit	(2.3)	(19.4)	(6)	(19.4)
Integration related costs	0.3	(2.8)	(3.1)	(2.8)
Other charges	(4)	(12.5)	(25.5)	(39)
Unallocated corporate items | Thailand
Information on reportable segments
Other charges	(0.4)	$ (12)	(8.5)	$ (38.7)
Unallocated corporate items | Huawei
Information on reportable segments
Other charges	$ (0.1)		$ (12.8)

Operating Segments and Geogra_5

Operating Segments and Geographic Information - Schedule of Percentage of Total Net Revenue Attributable to Reportable Segments (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Concentration Risk [Line Items]
Total net revenue	$ 402.8	$ 432.9	$ 1,310.5	$ 1,160.7
OpComms
Concentration Risk [Line Items]
Total net revenue	359.3	377.9	1,184.8	1,013.4
OpComms | Telecom and Datacom
Concentration Risk [Line Items]
Total net revenue	251	300.7	765.4	683.7
OpComms | Consumer and Industrial
Concentration Risk [Line Items]
Total net revenue	108.3	77.2	419.4	329.7
Lasers
Concentration Risk [Line Items]
Total net revenue	$ 43.5	$ 55	$ 125.7	$ 147.3
Product offerings | Revenue | OpComms
Concentration Risk [Line Items]
Concentration risk percentage	89.20%	87.30%	90.40%	87.30%
Product offerings | Revenue | OpComms | Telecom and Datacom
Concentration Risk [Line Items]
Concentration risk percentage	62.30%	69.50%	58.40%	58.90%
Product offerings | Revenue | OpComms | Consumer and Industrial
Concentration Risk [Line Items]
Concentration risk percentage	26.90%	17.80%	32.00%	28.40%
Product offerings | Revenue | Lasers
Concentration Risk [Line Items]
Concentration risk percentage	10.80%	12.70%	9.60%	12.70%

Operating Segments and Geogra_6

Operating Segments and Geographic Information - Schedule of Revenue by Geographic Region (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 28, 2020	Mar. 30, 2019	Mar. 28, 2020	Mar. 30, 2019
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 402.8	$ 432.9	$ 1,310.5	$ 1,160.7
Americas
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 73.2	$ 84.1	$ 210.4	$ 239.8
Americas | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	18.10%	19.40%	16.10%	20.70%
United States
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 38.6	$ 29.7	$ 118.9	$ 72.3
United States | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	9.60%	6.90%	9.10%	6.30%
Mexico
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 33.2	$ 53.5	$ 88.3	$ 164.8
Mexico | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	8.20%	12.30%	6.70%	14.20%
Other Americas
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 1.4	$ 0.9	$ 3.2	$ 2.7
Other Americas | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	0.30%	0.20%	0.30%	0.20%
Asia Pacific
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 302.2	$ 296.1	$ 1,003.3	$ 808.1
Asia Pacific | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	75.10%	68.40%	76.50%	69.60%
Hong Kong
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 125.9	$ 124.1	$ 404.2	$ 289.6
Hong Kong | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	31.30%	28.60%	30.80%	25.00%
South Korea
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 63.3	$ 23.6	$ 239.9	$ 154.9
South Korea | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	15.70%	5.50%	18.30%	13.30%
Japan
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 35.8	$ 50	$ 110.4	$ 129.2
Japan | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	8.90%	11.60%	8.40%	11.10%
Other Asia-Pacific
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 77.2	$ 98.4	$ 248.8	$ 234.4
Other Asia-Pacific | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	19.20%	22.70%	19.00%	20.20%
EMEA
Net revenue and identifiable assets by geographic regions
Total net revenue	$ 27.4	$ 52.7	$ 96.8	$ 112.8
EMEA | Geographic Concentration Risk | Total Net Revenue
Net revenue and identifiable assets by geographic regions
Concentration risk percentage	6.80%	12.20%	7.40%	9.70%

Operating Segments and Geogra_7

Operating Segments and Geographic Information - Schedule of Performance Obligations (Details) $ in Millions	Mar. 28, 2020USD ($)
Segment Reporting [Abstract]
Performance obligations	$ 546.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-03-29
Segment Reporting [Abstract]
Performance obligations	$ 513.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-06-28
Segment Reporting [Abstract]
Performance obligations	$ 32.7
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]: 2021-06-28
Segment Reporting [Abstract]
Performance obligations	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period

Operating Segments and Geogra_8

Operating Segments and Geographic Information - Schedule of Contract Balances (Details) - USD ($) $ in Millions	9 Months Ended
	Mar. 28, 2020	Jun. 29, 2019
Segment Reporting [Abstract]
Accounts receivable, net	$ 261.8	$ 238
Accounts receivable, net, change	$ 23.8
Accounts receivable, net, percentage change	10.00%
Deferred revenue and customer deposits	$ 1.7	$ 2.9
Deferred revenue and customer deposits, change	$ (1.2)
Deferred revenue and customer deposits, percentage change	(41.40%)

Operating Segments and Geogra_9

Operating Segments and Geographic Information - Schedule of Long-lived Assets by Geographic Region (Details) - USD ($) $ in Millions	Mar. 28, 2020	Jun. 29, 2019
Property, plant and equipment, net
Total long-lived assets	$ 410.1	$ 433.3
United States
Property, plant and equipment, net
Total long-lived assets	145.8	156.2
Thailand
Property, plant and equipment, net
Total long-lived assets	135.3	157.1
China
Property, plant and equipment, net
Total long-lived assets	43.3	33.5
Japan
Property, plant and equipment, net
Total long-lived assets	29.2	28.3
Other countries
Property, plant and equipment, net
Total long-lived assets	$ 56.5	$ 58.2

Uncategorized Items - lumentumf

Label	Element	Value
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (600,000)
Retained Earnings [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ (600,000)