Coherent 10-Q 12 Aug 20 2020 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Jul. 04, 2020	Aug. 10, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jul. 4, 2020
Document Transition Report	false
Entity File Number	001-33962
Entity Registrant Name	COHERENT, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	94-1622541
Entity Address, Address Line One	5100 Patrick Henry Drive
Entity Address, City or Town	Santa Clara
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	95054
City Area Code	408
Local Phone Number	764-4000
Title of each class	Common Stock, $0.01 par value
Trading Symbol	COHR
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		24,256,318
Entity Central Index Key	0000021510
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--10-03
Amendment flag	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Income Statement [Abstract]
Net sales	$ 298,330	$ 339,170	$ 912,248	$ 1,095,176
Cost of sales	203,053	241,167	613,607	717,106
Gross profit	95,277	98,003	298,641	378,070
Operating expenses:
Research and development	28,283	30,692	86,757	90,095
Selling, general and administrative	67,525	67,686	197,383	201,706
Goodwill and other impairment charges	0	0	451,025	0
Amortization of intangible assets	643	6,782	3,371	11,748
Total operating expenses	96,451	105,160	738,536	303,549
Income (loss) from operations	(1,174)	(7,157)	(439,895)	74,521
Other income (expense):
Interest income	269	257	906	903
Interest expense	(4,046)	(4,974)	(12,563)	(14,794)
Other—net	(505)	331	(1,322)	(3,898)
Total other expense, net	(4,282)	(4,386)	(12,979)	(17,789)
Income (loss) before income taxes	(5,456)	(11,543)	(452,874)	56,732
Provision for (benefit from) income taxes	3,252	(8,444)	(31,046)	3,531
Net income (loss)	$ (8,708)	$ (3,099)	$ (421,828)	$ 53,201
Net income (loss) per share:
Basic (in USD per share)	$ (0.36)	$ (0.13)	$ (17.52)	$ 2.20
Diluted (in USD per share)	$ (0.36)	$ (0.13)	$ (17.52)	$ 2.19
Shares used in computation:
Basic (shares)	24,159	24,054	24,075	24,185
Diluted (shares)	24,159	24,054	24,075	24,333

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ (8,708)	$ (3,099)	$ (421,828)	$ 53,201
Other comprehensive income (loss):
Translation adjustment, net of taxes	[1],[2]	8,183	2,762	(1,916)	(10,506)
Defined benefit pension plans, net of taxes	[1],[3]	(920)	(971)	690	(1,719)
Other comprehensive income (loss), net of tax	[1]	7,263	1,791	(1,226)	(12,225)
Comprehensive income (loss)		(1,445)	(1,308)	(423,054)	40,976
Translation adjustment, net of taxes		2,268	(535)	1,459	2,911
Defined benefit plans, tax benefits		$ (445)	$ 322	$ 230	$ 605
[1]	Reclassification adjustments were not significant during the three and nine months ended July 4, 2020 and June 29, 2019.
[2]	Tax expenses of $2,268 and $1,459 were provided on translation adjustments during the three and nine months ended July 4, 2020, respectively. Tax expenses (benefits) of $535 and $(2,911) were provided on translation adjustments during the three and nine months ended June 29, 2019, respectively.
[3]	Tax expenses (benefits) of $(445) and $230 were provided on changes in defined benefit pension plans for the three and nine months ended July 4, 2020, respectively. Tax benefits of $322 and $605 were provided on changes in defined benefit pension plans for the three and nine months ended June 29, 2019, respectively.

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 04, 2020	Sep. 28, 2019
Current assets:
Cash and cash equivalents	$ 378,992	$ 305,833
Restricted cash	736	792
Short-term investments	41,898	120
Accounts receivable—net of allowances of $6,838 and $8,690, respectively	197,757	267,553
Inventories	448,972	442,530
Prepaid expenses and other assets	90,237	77,993
Total current assets	1,158,592	1,094,821
Property and equipment, net	251,453	323,434
Goodwill	98,647	427,101
Intangible assets, net	24,005	84,813
Non-current restricted cash	4,486	12,036
Other assets	232,942	140,964
Total assets	1,770,125	2,083,169
Current liabilities:
Short-term borrowings and current-portion of long-term obligations	16,554	14,863
Accounts payable	68,484	51,531
Income taxes payable	3,922	6,185
Other current liabilities	174,557	167,735
Total current liabilities	263,517	240,314
Long-term obligations	397,264	392,238
Other long-term liabilities	215,838	165,881
Commitments and contingencies (Note 13)
Stockholders' equity:
Common stock, value	241	238
Additional paid-in capital	66,141	34,320
Accumulated other comprehensive loss	(37,562)	(36,336)
Retained earnings	864,686	1,286,514
Total stockholders’ equity	893,506	1,284,736
Total liabilities and stockholders’ equity	$ 1,770,125	$ 2,083,169

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 04, 2020	Sep. 28, 2019
Statement of Financial Position [Abstract]
Accounts Receivable, Allowance for Credit Loss	$ 6,597	$ 8,690
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	500,000,000	500,000,000
Common Stock, Shares, Outstanding	24,256,000	23,982,000

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total		Common Stock	Add. Paid-in Capital	Accum. Other Comp. Income (Loss)	Retained Earnings
Beginning balance at Sep. 29, 2018		$ 1,314,464		$ 242	$ 78,700	$ 2,833	$ 1,232,689
Beginning balance (in shares) at Sep. 29, 2018				24,299,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		(9,139)		$ 2	(9,141)
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				223,000
Repurchase of common stock		(25,501)		$ (2)	(25,499)
Repurchase of common stock (in shares)				(195,000)
Stock-based compensation		7,791			7,791
Net income		35,550					35,550
Other comprehensive income (loss), net of tax		(5,682)				(5,682)
Ending balance at Dec. 29, 2018		1,317,483		$ 242	51,851	(2,849)	1,268,239
Ending balance (in shares) at Dec. 29, 2018				24,327,000
Beginning balance at Sep. 29, 2018		1,314,464		$ 242	78,700	2,833	1,232,689
Beginning balance (in shares) at Sep. 29, 2018				24,299,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		53,201
Other comprehensive income (loss), net of tax	[1]	(12,225)
Ending balance at Jun. 29, 2019		1,301,211		$ 238	24,475	(9,392)	1,285,890
Ending balance (in shares) at Jun. 29, 2019				23,982,000
Beginning balance at Dec. 29, 2018		1,317,483		$ 242	51,851	(2,849)	1,268,239
Beginning balance (in shares) at Dec. 29, 2018				24,327,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		(298)			(298)
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				10,000
Repurchase of common stock		(25,905)		$ (2)	(25,903)
Repurchase of common stock (in shares)				(200,000)
Stock-based compensation		9,086			9,086
Net income		20,750					20,750
Other comprehensive income (loss), net of tax		(8,334)				(8,334)
Ending balance at Mar. 30, 2019		1,312,782		$ 240	34,736	(11,183)	1,288,989
Ending balance (in shares) at Mar. 30, 2019				24,137,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		6,081			6,081
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				54,000
Repurchase of common stock		(26,004)		$ (2)	(26,002)
Repurchase of common stock (in shares)				(209,000)
Stock-based compensation		9,660			9,660
Net income		(3,099)					(3,099)
Other comprehensive income (loss), net of tax		1,791	[1]			1,791
Ending balance at Jun. 29, 2019		1,301,211		$ 238	24,475	(9,392)	1,285,890
Ending balance (in shares) at Jun. 29, 2019				23,982,000
Beginning balance at Sep. 28, 2019		$ 1,284,736		$ 238	34,320	(36,336)	1,286,514
Beginning balance (in shares) at Sep. 28, 2019		23,982,000		23,982,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		$ (7,428)		$ 2	(7,430)
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				171,000
Stock-based compensation		7,574			7,574
Net income		5,793					5,793
Other comprehensive income (loss), net of tax		15,300				15,300
Ending balance at Dec. 28, 2019		1,305,975		$ 240	34,464	(21,036)	1,292,307
Ending balance (in shares) at Dec. 28, 2019				24,153,000
Beginning balance at Sep. 28, 2019		$ 1,284,736		$ 238	34,320	(36,336)	1,286,514
Beginning balance (in shares) at Sep. 28, 2019		23,982,000		23,982,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income		$ (421,828)
Other comprehensive income (loss), net of tax	[1]	(1,226)
Ending balance at Jul. 04, 2020		$ 893,506		$ 241	66,141	(37,562)	864,686
Ending balance (in shares) at Jul. 04, 2020		24,256,000		24,256,000
Beginning balance at Dec. 28, 2019		$ 1,305,975		$ 240	34,464	(21,036)	1,292,307
Beginning balance (in shares) at Dec. 28, 2019				24,153,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		950			950
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				39,000
Stock-based compensation		9,207			9,207
Net income		(418,913)					(418,913)
Other comprehensive income (loss), net of tax		(23,789)				(23,789)
Ending balance at Apr. 04, 2020		873,430		$ 240	44,621	(44,825)	873,394
Ending balance (in shares) at Apr. 04, 2020				24,192,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		6,320		$ 1	6,319
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				64,000
Stock-based compensation		15,201			15,201
Net income		(8,708)					(8,708)
Other comprehensive income (loss), net of tax		7,263	[1]			7,263
Ending balance at Jul. 04, 2020		$ 893,506		$ 241	$ 66,141	$ (37,562)	$ 864,686
Ending balance (in shares) at Jul. 04, 2020		24,256,000		24,256,000
[1]	Reclassification adjustments were not significant during the three and nine months ended July 4, 2020 and June 29, 2019.

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019
Cash flows from operating activities:
Net income (loss)	$ (421,828)	$ 53,201
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	36,257	41,462
Amortization of intangible assets	27,166	47,725
Impairment of goodwill	327,203	0
Impairment of long-lived assets	121,350	0
Impairment of investment	2,472	0
Deferred income taxes	(21,797)	(8,209)
Amortization of debt issuance cost	2,451	3,810
Stock-based compensation	31,076	26,535
Non-cash restructuring charges	2,068	12,121
Amortization of operating right of use assets	12,146	0
Other non-cash expense (income)	1,647	(2,498)
Changes in assets and liabilities, net of effect of acquisitions:
Accounts receivable	71,723	85,090
Inventories	(164)	1,719
Prepaid expenses and other assets	(626)	8,327
Other long-term assets	1,391	1,661
Accounts payable	14,716	(5,218)
Income taxes payable/receivable	(33,642)	(115,413)
Operating lease liabilities	(12,342)	0
Other current liabilities	(5,194)	(16,737)
Other long-term liabilities	3,991	1,788
Net cash provided by operating activities	160,064	135,364
Cash flows from investing activities:
Purchases of property and equipment	(48,436)	(60,511)
Proceeds from dispositions of property and equipment	668	5,228
Purchases of available-for-sale securities	(42,018)	(11,552)
Proceeds from sales and maturities of available-for-sale securities	240	9,557
Acquisition of businesses, net of cash acquired	0	(18,881)
Investment at cost	0	(3,423)
Net cash used in investing activities	(89,546)	(79,582)
Cash flows from financing activities:
Short-term borrowings	12,695	107,054
Repayments of short-term borrowings	(14,010)	(68,720)
Repayments of long-term borrowings	(5,865)	(5,686)
Issuance of common stock under employee stock option and purchase plans	13,361	11,811
Net settlement of restricted common stock	(13,519)	(15,167)
Repurchase of common stock	0	(77,410)
Net cash used in financing activities	(7,338)	(48,118)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	2,373	(1,940)
Net increase in cash, cash equivalents and restricted cash	65,553	5,724
Cash, cash equivalents and restricted cash, beginning of period	318,661	324,045
Cash, cash equivalents and restricted cash, end of period	384,214	329,769
Non-cash investing and financing activities:
Unpaid property and equipment purchases	$ 5,826	$ 4,985

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - Reconciliation - USD ($) $ in Thousands	Jul. 04, 2020	Sep. 28, 2019	Jun. 29, 2019	Sep. 29, 2018
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 378,992	$ 305,833	$ 316,458
Restricted cash, current	736	792	825
Restricted cash, non-current	4,486	12,036	12,486
Total cash, cash equivalents, and restricted cash shown in the condensed consolidated statement of cash flows	$ 384,214	$ 318,661	$ 329,769	$ 324,045

Recent Accounting Standards (Po

Recent Accounting Standards (Policies)	9 Months Ended
	Jul. 04, 2020
Accounting Policies [Abstract]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification	Adoption of New Accounting Pronouncement In December 2019, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2019-12, Simplifying the Accounting for Income Taxes. The ASU updates specific areas of ASC 740, Income Taxes, to reduce complexity while maintaining or improving the usefulness of the information provided to users of financial statements. We elected to early adopt ASU 2019-12 in the second quarter of fiscal 2020 with no material impact to our condensed consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The guidance 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 material impact to our condensed consolidated financial statements. In February 2016, the FASB issued accounting guidance (ASC 842) that modifies lease accounting for lessees to increase transparency and comparability by recording lease assets and liabilities for operating leases and disclosing key information about leasing arrangements. We adopted ASC 842 in the first quarter of fiscal 2020 utilizing the optional transition method by applying the new standard to leases existing at the date of initial application and not restating comparative periods. We determine if an arrangement contains a lease at inception for arrangements with an initial term of more than 12 months, and classify it as either finance or operating. We have elected the package of practical expedients which allows us to not reassess 1) whether any expired or existing contracts are or contain leases; 2) the lease classification for any expired or existing leases; and 3) initial direct costs for any existing leases. In addition, we also elected to use the practical expedient allowed in the standard to not separate lease and non-lease components and apply the short-term lease measurement and recognition exemption to all leases shorter than 12 months when calculating the lease liability under ASC 842. The adoption of the standard resulted in the recognition of operating lease assets of $90.4 million, with corresponding operating lease liabilities of $93.5 million on our condensed consolidated balance sheet, primarily related to real estate leases. The difference between the operating lease right-of-use assets and operating lease liabilities primarily represents our deferred rent as of adoption. As of the date of adoption, we recognized finance lease assets of $1.0 million, with corresponding finance lease liabilities of $0.9 million on our condensed consolidated balance sheet, primarily related to equipment leases. See Note 11, "Leases" for more information.
Recent Accounting Standards	Recently Issued Accounting Pronouncements In June 2016, the 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. The new standard will become effective for our fiscal year 2021, which begins on October 4, 2020. We are currently evaluating the impact of our pending adoption of Topic 326 on our consolidated financial statements. We currently expect that the standard will not have a material impact on our consolidated statements of operations.

Basis of Presentation

Basis of Presentation	9 Months Ended
	Jul. 04, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	BASIS OF PRESENTATION The accompanying unaudited condensed consolidated financial statements have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") have been condensed or omitted pursuant to such rules and regulations. These interim condensed consolidated financial statements and notes thereto should be read in conjunction with the consolidated financial statements and notes thereto filed by Coherent, Inc. on Form 10-K for the fiscal year ended September 28, 2019. In the opinion of management, all adjustments necessary for a fair presentation of financial condition and results of operation as of and for the periods presented have been made and include only normal recurring adjustments. Interim results of operations are not necessarily indicative of results to be expected for the year or any other interim periods. Our fiscal year ends on the Saturday closest to September 30 and our third fiscal quarter includes 13 weeks of operations in each fiscal year presented. Fiscal 2020 includes 53 weeks and fiscal 2019 includes 52 weeks. The consolidated financial statements include the accounts of Coherent, Inc. and its direct and indirect subsidiaries (collectively, the "Company", "we", "our", "us" or "Coherent"). Intercompany balances and transactions have been eliminated. The preparation of consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. The COVID-19 pandemic has significantly increased economic uncertainty and decreased demand for our products in many markets we serve, which could continue for an unknown period of time. In these circumstances, there may be developments outside of our control, including the length and extent of the COVID-19 outbreak, government-imposed measures and our ability to ship products and/or service installed products that may require us to adjust our operating plans. As such, given the dynamic nature of this situation, we cannot predict the future impacts of COVID-19 on our financial condition, results of operations or cash flows. However, we do expect that it will have an adverse impact on our revenue as well as our overall profitability and may lead to an increase in inventory provisions, allowances for credit losses, and a volatile effective tax rate driven by changes in the mix of earnings across our markets. Based on our internal projections and the preparation of our financial statements for the quarter ended April 4, 2020, and considering the forecasted decrease in demand due to the COVID-19 pandemic and other factors, we believed that the fair value of our Industrial Lasers & Systems ("ILS") reporting unit might no longer have exceeded its carrying value and performed an interim goodwill impairment test on the ILS and OEM Laser Sources ("OLS") reporting units. Based on the estimated fair value of the ILS reporting unit, we recorded non-cash pre-tax goodwill impairment charges of $327.2 million in the quarter ended April 4, 2020. In addition, we performed impairment tests on the long-lived assets allocated to the asset group of the ILS reporting unit, including intangible assets, property, plant and equipment and ROU assets as of April 4, 2020 and recorded non-cash pre-tax charges in the quarter ended April 4, 2020 related to the impairment of intangible assets, property, plant and equipment and ROU assets of the ILS reporting unit of $33.9 million, $85.6 million and $1.8 million, respectively. See Note 8, "Goodwill and Intangible Assets" and Note 11, "Leases" in the Notes to Condensed Consolidated Financial Statements. Change in Accounting Policies - Leasing Except for the adoption of Accounting Standards Update ("ASU") 2016-02, Leases ("ASC 842") on September 29, 2019 and the resulting changes in our accounting policies and disclosures for lease accounting, there have been no significant changes to our significant accounting policies as of and for the nine months ended July 4, 2020, as compared to the significant accounting policies described in our Annual Report on Form 10-K for our fiscal year ended September 28, 2019. Effective September 29, 2019, we adopted ASC 842, using the optional transition method, by which companies may elect not to recast the comparative periods presented in financial statements in the period of adoption and recognize a cumulative effect adjustment in the period of adoption. See Note 2, "Recent Accounting Standards" to the Notes to Condensed Consolidated Financial Statements 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 other assets and finance lease liabilities within other current and other long-term liabilities on our condensed consolidated balance sheets. 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 other assets and operating lease liabilities within other current and other long-term liabilities 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. Most of our leases do not provide an implicit rate. We use our incremental borrowing rate for the same jurisdiction and term as the associated lease based on the information available at the lease commencement date to determine the present value of the lease payments. We used the incremental borrowing rate as of September 28, 2019 for operating leases that commenced prior to that date. 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.

Recent Accounting Standards

Recent Accounting Standards	9 Months Ended
	Jul. 04, 2020
Accounting Policies [Abstract]
Recent Accounting Standards	RECENT ACCOUNTING STANDARDS Adoption of New Accounting Pronouncement In December 2019, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2019-12, Simplifying the Accounting for Income Taxes. The ASU updates specific areas of ASC 740, Income Taxes, to reduce complexity while maintaining or improving the usefulness of the information provided to users of financial statements. We elected to early adopt ASU 2019-12 in the second quarter of fiscal 2020 with no material impact to our condensed consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income. The guidance 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 material impact to our condensed consolidated financial statements. In February 2016, the FASB issued accounting guidance (ASC 842) that modifies lease accounting for lessees to increase transparency and comparability by recording lease assets and liabilities for operating leases and disclosing key information about leasing arrangements. We adopted ASC 842 in the first quarter of fiscal 2020 utilizing the optional transition method by applying the new standard to leases existing at the date of initial application and not restating comparative periods. We determine if an arrangement contains a lease at inception for arrangements with an initial term of more than 12 months, and classify it as either finance or operating. We have elected the package of practical expedients which allows us to not reassess 1) whether any expired or existing contracts are or contain leases; 2) the lease classification for any expired or existing leases; and 3) initial direct costs for any existing leases. In addition, we also elected to use the practical expedient allowed in the standard to not separate lease and non-lease components and apply the short-term lease measurement and recognition exemption to all leases shorter than 12 months when calculating the lease liability under ASC 842. The adoption of the standard resulted in the recognition of operating lease assets of $90.4 million, with corresponding operating lease liabilities of $93.5 million on our condensed consolidated balance sheet, primarily related to real estate leases. The difference between the operating lease right-of-use assets and operating lease liabilities primarily represents our deferred rent as of adoption. As of the date of adoption, we recognized finance lease assets of $1.0 million, with corresponding finance lease liabilities of $0.9 million on our condensed consolidated balance sheet, primarily related to equipment leases. See Note 11, "Leases" for more information. Recently Issued Accounting Pronouncements In June 2016, the 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. The new standard will become effective for our fiscal year 2021, which begins on October 4, 2020. We are currently evaluating the impact of our pending adoption of Topic 326 on our consolidated financial statements. We currently expect that the standard will not have a material impact on our consolidated statements of operations.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Jul. 04, 2020
Revenue from Contract with Customer [Abstract]
Revenue Recognition	REVENUE RECOGNITION Disaggregation of Revenue Based on the information that our chief operating decision maker ("CODM") uses to manage the business, we disaggregate revenue by type and market application within each segment. No other level of disaggregation is required considering the type of products, customers, markets, contracts, duration of contracts, timing of transfer of control and sales channels. The following tables summarize revenue from contracts with customers (in thousands): Sales by revenue type and segment Three Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 109,995 $ 91,114 $ 115,992 $ 104,784 Other product and service revenues (2) 74,699 22,522 90,293 28,101 Total net sales $ 184,694 $ 113,636 $ 206,285 $ 132,885 (1) Net sales primarily recognized at a point in time. (2) Includes sales of spare parts, related accessories and other consumable parts as well as revenues from service agreements, of which $15.4 million and $14.1 million for the three months ended July 4, 2020 and June 29, 2019, respectively, were recognized over time. Nine Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 321,691 $ 277,710 $ 412,629 $ 329,537 Other product and service revenues (2) 237,673 75,174 267,601 85,409 Total net sales $ 559,364 $ 352,884 $ 680,230 $ 414,946 (1) Net sales primarily recognized at a point in time. (2) Includes sales of spare parts, related accessories and other consumable parts as well as revenues from service agreements, of which $46.3 million and $40.1 million for the nine months ended July 4, 2020 and June 29, 2019, respectively, were recognized over time. Sales by market application and segment Three Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 123,635 $ 18,207 $ 126,754 $ 16,467 Materials processing 7,581 74,156 11,207 90,198 OEM components and instrumentation 33,588 19,903 39,997 24,300 Scientific and government programs 19,890 1,370 28,327 1,920 Total net sales $ 184,694 $ 113,636 $ 206,285 $ 132,885 Nine Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 343,429 $ 50,726 $ 441,597 $ 49,298 Materials processing 26,373 230,043 29,493 281,477 OEM components and instrumentation 120,502 65,903 119,027 78,825 Scientific and government programs 69,060 6,212 90,113 5,346 Total net sales $ 559,364 $ 352,884 $ 680,230 $ 414,946 See Note 19, "Segment and Geographic Information" for revenue disaggregation by reportable segment and geographic region. Contract Balances We record accounts receivable when we have an unconditional right to the consideration. Contract liabilities are recorded when cash payments are received or due in advance of performance. Contract liabilities consist of customer deposits and deferred revenue, where we have unsatisfied or partly satisfied performance obligations. Contract liabilities classified as customer deposits are included in other current liabilities and contract liabilities classified as deferred revenue are included in other current liabilities or other long-term liabilities on our condensed consolidated balance sheets. Payment terms vary by customer. A rollforward of our customer deposits and deferred revenue is as follows (in thousands): Beginning balance, September 28, 2019 (1) $ 42,550 Additions to customer deposits and deferred revenue 137,747 Amount of customer deposits and deferred revenue recognized in income (2) (126,501) Translation adjustments 260 Ending balance, July 4, 2020 (3) $ 54,056 (1) Beginning customer deposits and deferred revenue as of September 28, 2019 include $34,538 of current portion and $8,012 of long-term portion. (2) Amount of customer deposits and deferred revenue recognized in the three months ended July 4, 2020 was $48,674. (3) Ending customer deposits and deferred revenue as of July 4, 2020 include $41,329 of current portion and $12,727 of long-term portion. Remaining performance obligations represent the transaction price allocated to performance obligations that are unsatisfied or partially unsatisfied as of the end of the reporting period. The following table includes estimated revenue expected to be recognized in the future related to performance obligations for sales of maintenance agreements, extended warranties, installation, and contracts with customer acceptance provisions included in customer deposits and deferred revenue as of July 4, 2020 (in thousands): Remainder of fiscal 2020 Thereafter Total Performance obligations as of July 4, 2020 $ 27,120 $ 26,936 $ 54,056

Business Combinations

Business Combinations	9 Months Ended
	Jul. 04, 2020
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS Fiscal 2019 Acquisitions Ondax On October 5, 2018, we acquired privately held Ondax for approximately $12.0 million, excluding transaction costs. Ondax developed and produced photonic components which are used on an OEM basis by the laser industry as well as incorporated into its own stabilized lasers and Raman Spectroscopy systems. Ondax’s operating results have been included in our Industrial Lasers & Systems segment. See Note 19, "Segment and Geographic Information." Our allocation of the purchase price is as follows (in thousands): Tangible assets: Cash $ 103 Accounts receivable 534 Inventories 1,793 Prepaid expenses and other assets 17 Deferred tax assets 681 Property and equipment 122 Liabilities assumed (499) Intangible assets: Existing technology 5,600 Customer relationships 300 Goodwill 3,333 Total $ 11,984 Results of operations for the business have been included in our condensed consolidated financial statements subsequent to the date of acquisition and pro forma results of operations in accordance with authoritative guidance for prior periods have not been presented because the effect of the acquisition was not material to our prior period consolidated financial results. The identifiable intangible assets are being amortized over their respective useful lives of 1 to 8 years. The fair values of the acquired intangibles were determined using the income approach. In performing these valuations, the key underlying probability-adjusted assumptions of the discounted cash flows were projected revenues, gross margin expectations and operating cost estimates. The valuations were based on the information that was available as of the acquisition date and the expectations and assumptions that have been deemed reasonable by our management. There are inherent uncertainties and management judgment required in these determinations. This acquisition resulted in a purchase price that exceeded the estimated fair value of tangible and intangible assets, which was allocated to goodwill. In the quarter ended April 4, 2020, we performed an interim impairment test and the entire goodwill balance and a portion of the existing technology intangible assets were impaired. See Note 8, "Goodwill and Intangible Assets". We believe the amount of goodwill relative to identifiable intangible assets relates to several factors including: (1) potential buyer-specific synergies related to the development of new technologies; and (2) the potential to leverage our sales force to attract new customers. None of the goodwill from this purchase is deductible for tax purposes. Quantum On October 5, 2018, we acquired certain assets of Quantum Coating, Inc. ("Quantum") for approximately $7.0 million, excluding transaction costs, and accounted for the transaction as an asset purchase. Our allocation of the purchase price is as follows (in thousands): Tangible assets: Property and equipment $ 2,770 Intangible assets: Existing technology 1,600 Customer relationships 230 Production know-how 2,300 Backlog 100 Total $ 7,000

Fair Values

Fair Values	9 Months Ended
	Jul. 04, 2020
Fair Value Disclosures [Abstract]
Fair Values	FAIR VALUES We have not changed our valuation techniques in measuring the fair value of any financial assets and liabilities during the period. We recognize transfers between levels within the fair value hierarchy, if any, at the end of each quarter. There were no transfers between levels during the periods presented. As of July 4, 2020 and September 28, 2019, we had one investment carried on a cost basis. See Note 9, "Balance Sheet Details." If we were to fair value this investment, it would be based upon Level 3 inputs. This investment is not considered material to our condensed consolidated financial statements. We measure the fair value of outstanding debt obligations for disclosure purposes on a recurring basis. As of July 4, 2020, the current and long-term portion of long-term obligations of $6.6 million and $397.3 million, respectively, are reported at amortized cost. As of September 28, 2019, the current and long-term portion of long-term obligations of $4.9 million and $392.2 million, respectively, are reported at amortized cost. These outstanding obligations are classified as Level 2 as they are not actively traded and are valued using a discounted cash flow model that uses observable market inputs. Based on the discounted cash flow model, the fair value of the outstanding debt approximates amortized cost. Financial assets and liabilities measured at fair value as of July 4, 2020 and September 28, 2019 are summarized below (in thousands): Aggregate Fair Value Quoted Prices Significant Aggregate Fair Value Quoted Prices Significant July 4, 2020 September 28, 2019 (Level 1) (Level 2) (Level 1) (Level 2) Assets: Cash equivalents: Money market fund deposits $ 59,052 $ 59,052 $ — $ 21,422 $ 21,422 $ — Certificates of deposit 13,200 13,200 — — — — Short-term investments: U.S. Treasury and agency obligations (1) 115 — 115 120 — 120 Certificates of deposit 41,783 41,783 — — — — Prepaid and other assets: Foreign currency contracts (2) 589 — 589 370 — 370 Money market fund deposits — Deferred comp and supplemental plan (3) 193 193 — 433 433 — Mutual funds — Deferred comp and supplemental plan (3) 19,941 19,941 — 22,419 22,419 — Total $ 134,873 $ 134,169 $ 704 $ 44,764 $ 44,274 $ 490 Liabilities: Other current liabilities: Foreign currency contracts (2) (845) — (845) (960) — (960) Total $ 134,028 $ 134,169 $ (141) $ 43,804 $ 44,274 $ (470) ___________________________________________________ (1) Valuations are based upon quoted market prices in active markets involving similar assets. The market inputs used to value these instruments generally consist of market yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. Pricing sources include industry standard data providers, security master files from large financial institutions, and other third party sources which are input into a distribution-curve-based algorithm to determine a daily market value. This creates a "consensus price" or a weighted average price for each security. (2) The principal market in which we execute our foreign currency contracts is the institutional market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large commercial banks. Our foreign currency contracts’ valuation inputs are based on quoted prices and quoted pricing intervals from public data sources and do not involve management judgment. See Note 7, "Derivative Instruments and Hedging Activities."

Short-Term Investments

Short-Term Investments	9 Months Ended
	Jul. 04, 2020
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Short-Term Investments	SHORT-TERM INVESTMENTS We consider all highly liquid investments with maturities of three months or less at the time of purchase to be cash equivalents. Investments classified as available-for-sale are reported at fair value with unrealized gains and losses, net of related income taxes, recorded as a separate component of other comprehensive income ("OCI") in stockholders’ equity until realized. Interest and amortization of premiums and discounts for debt securities are included in interest income. Gains and losses on securities sold are determined based on the specific identification method and are included in other income (expense). Cash, cash equivalents and short-term investments consist of the following (in thousands): July 4, 2020 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 378,992 $ — $ — $ 378,992 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 115 $ — $ — $ 115 Certificates of deposit 41,783 — — 41,783 Total short-term investments $ 41,898 $ — $ — $ 41,898 September 28, 2019 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 305,833 $ — $ — $ 305,833 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 120 $ — $ — $ 120 Total short-term investments $ 120 $ — $ — $ 120 There were no unrealized gains or losses at July 4, 2020 or September 28, 2019.

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Jul. 04, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES We maintain operations in various countries outside of the United States and have foreign subsidiaries that manufacture and sell our products in various global markets. The majority of our sales are transacted in U.S. dollars. However, we do generate revenues in other currencies, primarily the Euro, Japanese Yen, South Korean Won, Singapore Dollar and Chinese Renminbi (RMB). As a result, our earnings, cash flows and cash balances are exposed to fluctuations in foreign currency exchange rates. We attempt to limit these exposures through financial market instruments. We utilize derivative instruments, primarily forward contracts with maturities of two months or less, to manage our exposure associated with anticipated cash flows and net asset and liability positions denominated in foreign currencies. Gains and losses on the forward contracts are mitigated by gains and losses on the underlying instruments. We do not use derivative financial instruments for speculative or trading purposes. The credit risk amounts represent our gross exposure to potential accounting loss on derivative instruments that are outstanding or unsettled if all counterparties failed to perform according to the terms of the contract, based on then-current currency rates at each respective date. Non-Designated Derivatives The total outstanding notional contract and fair value asset (liability) amounts of non-designated hedge contracts, with maximum maturity of two months, are as follows (in thousands): U.S. Notional Contract Value U.S. Fair Value July 4, 2020 September 28, 2019 July 4, 2020 September 28, 2019 Foreign currency hedge contracts Purchase $ 70,682 $ 53,920 $ 464 $ (117) Sell $ (86,375) $ (86,984) $ (720) $ (473) The fair value of our derivative instruments is included in prepaid expenses and other assets and in other current liabilities in our Condensed Consolidated Balance Sheets. See Note 5, "Fair Values." During the three and nine months ended July 4, 2020, we recognized gains of $1.1 million and $1.2 million, respectively, in other income (expense) for derivative instruments not designated as hedging instruments. During the three and nine months ended June 29, 2019, we recognized gains of $0.9 million and losses of $5.8 million, respectively, in other income (expense) for derivative instruments not designated as hedging instruments. Master Netting Arrangements To mitigate credit risk in derivative transactions, we enter into master netting arrangements that allow each counterparty in the arrangements to net settle amounts of multiple and separate derivative transactions under certain conditions. We present the fair value of derivative assets and liabilities within our condensed consolidated balance sheet on a gross basis even when derivative transactions are subject to master netting arrangements and may otherwise qualify for net presentation. The impact of netting derivative assets and liabilities is not material to our financial position for any of the periods presented. Our derivative contracts do not contain any credit risk related contingent features and do not require collateral or other security to be furnished by us or the counterparties.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	9 Months Ended
	Jul. 04, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS During the quarter ended July 4, 2020, we noted no indications of impairment or triggering events, not already considered in the quarter ended April 4, 2020, to cause us to review goodwill for potential impairment. We will conduct our annual goodwill testing during the fourth fiscal quarter. In the quarter ended April 4, 2020, the worldwide spread of coronavirus ("COVID-19") created significant volatility, uncertainty and disruption to the global economy, representing an indicator to test our goodwill for impairment. Based on our internal projections and the preparation of our financial statements for the quarter ended April 4, 2020, and considering the forecasted decrease in demand due to the COVID-19 pandemic and other factors, we believed that the fair value of our ILS reporting unit might no longer have exceeded its carrying value and performed an interim goodwill impairment test on the ILS reporting unit. We also performed an interim goodwill impairment test on the OLS reporting unit. Our goodwill impairment tests for the ILS and OLS reporting units were performed by comparing the fair value of the reporting units with their carrying values and recognizing an impairment charge for the amount by which the carrying value exceeded the fair value. Based on the estimated fair value of the ILS reporting unit, in the quarter ended April 4, 2020, we recorded a non-cash pre-tax charge related to the ILS reporting unit of $327.2 million, reducing the goodwill balance of the reporting unit to zero. The impairment charge was primarily the result of a decline in projected cash flows of the ILS reporting unit driven by lower forecasted sales volumes and profitability in several business units. The impairment charge was also the result of changes in certain market-related inputs to the analysis to reflect macro-economic changes caused by the impact of COVID-19, including lower pricing multiples for comparable public companies. No impairment charge was recognized for the OLS reporting unit as the fair value significantly exceeded the carrying value of the reporting unit. In assessing goodwill for impairment, we were required to make significant judgments related to the fair value of our reporting units. We used a combination of the Income (discounted cash flow) approach and the Market (market comparable) approach to estimate the fair value of our reporting units. The Income approach utilizes the discounted cash flow model to provide an estimation of fair value based on the cash flows that a business expects to generate. These cash flows are based on forecasts developed internally by management which are then discounted at an after tax rate of return required by equity and debt market participants of a business enterprise. Our assumptions used in the forecasts are based on historical data, supplemented by current and anticipated market conditions, estimated growth rates and management’s plans. The rate of return on cost of capital is weighted based on the capitalization of comparable companies. We utilized a discount rate for each of our reporting units that represents the risks that our businesses face, considering their sizes, their current economic environment and other industry data as we believe is appropriate. The Market approach determines fair value by comparing the reporting units to comparable companies in similar lines of business that are publicly traded. The selection of comparable companies is based on the markets in which the reporting units operate giving consideration to risk profiles, size, geography and diversity of products and services. Total Enterprise Value (TEV) multiples such as TEV to revenues and TEV to earnings (if applicable) before interest and taxes of the publicly traded companies are calculated. We utilized multiples for each of our reporting units that represent the risks that our businesses face, considering their sizes, their current economic environment and other industry data as we believe is appropriate. The interim goodwill impairment testing results were also reconciled with our market capitalization as of April 4, 2020, as the final step in the impairment testing. Before performing the goodwill impairment test for the ILS reporting unit, we performed impairment tests on the long-lived assets allocated to the asset group of the ILS reporting unit, including intangible assets, property, plant and equipment and ROU assets as of April 4, 2020, due primarily to the same indicators that led to the interim goodwill impairment testing. Based on the impairment tests performed, we concluded that some of the long-lived assets allocated to the asset group of the ILS reporting unit were impaired as of April 4, 2020. Accordingly, we recorded non-cash pre-tax charges in the quarter ended April 4, 2020 related to the intangible assets, property, plant and equipment and right-of-use ("ROU") assets of the ILS reporting unit of $33.9 million, $85.6 million and $1.8 million, respectively. We did not identify any indicators that would lead us to believe that the carrying value of the long-lived assets allocated to the asset group of the OLS reporting unit may not be recoverable as of April 4, 2020. In assessing our long-lived assets for impairment, we were required to make significant judgments related to the fair value of our long-lived assets, which are comprised of personal property, real property, and intangible assets. We used a combination of the Income, the Market approach, and the Cost (cost to create) approach to estimate the fair value of our long-lived assets. Our personal property assets consist of laser manufacturing and assembly equipment, semiconductor tools, laboratory and test equipment, furniture and fixtures and computer hardware and software. We used the Cost Approach (with support from the Market Approach) to estimate the fair value of our personal property, taking into consideration the physical deterioration, functional obsolescence and economic obsolescence of our personal property assets. Our real property assets consist of land and buildings, land rights (ground leased) and ROU assets. In determining the fair value of our real property assets, we used a combination of the Income, Market (sales comparison) and Cost approaches. We considered historical transaction information, current market conditions, operating performance, forecast growth and market-derived rates of return in our real property determination of fair value. The fair value of our ROU assets was determined using the Income approach by considering off-market components of the associated ROU leases. Our intangible assets consist of technology and customer relationship assets, and we used the Income approach to estimate the fair value of our intangible assets. We identified cash flows associated with each intangible asset, which were discounted at an after-tax rate of return appropriate for the risk profile of each intangible asset. The changes in the carrying amount of goodwill by segment for the period from September 28, 2019 to July 4, 2020 are as follows (in thousands): OEM Laser Sources Industrial Lasers & Systems Total Balance as of September 28, 2019 $ 96,820 $ 330,281 $ 427,101 Impairment charges — (327,203) (327,203) Translation adjustments 1,827 (3,078) (1,251) Balance as of July 4, 2020 $ 98,647 $ — $ 98,647 Components of our amortizable intangible assets are as follows (in thousands): July 4, 2020 September 28, 2019 Gross Accumulated Net Gross Accumulated Net Existing technology $ 43,114 $ (32,181) $ 10,933 $ 193,704 $ (131,429) $ 62,275 Customer relationships 24,076 (12,503) 11,573 42,083 (21,512) 20,571 Trade name — — — 5,261 (5,138) 123 Production know-how 2,300 (801) 1,499 2,300 (456) 1,844 Total $ 69,490 $ (45,485) $ 24,005 $ 243,348 $ (158,535) $ 84,813 For accounting purposes, when an intangible asset is fully amortized, it is removed from the disclosure schedule. The gross carrying amounts as of July 4, 2020, have been reduced by impairment charges of $27.7 million and $6.2 million for existing technology and customer relationships, respectively. Amortization expense for intangible assets for the nine months ended July 4, 2020 and June 29, 2019 was $27.2 million and $47.7 million, respectively. The change in the accumulated amortization also includes $1.8 million (decrease) and $2.1 million (decrease) of foreign exchange impact for the nine months ended July 4, 2020 and June 29, 2019, respectively. At July 4, 2020, estimated amortization expense for the remainder of fiscal 2020, the next five succeeding fiscal years and all fiscal years thereafter are as follows (in thousands): Estimated Amortization 2020 (remainder) $ 2,918 2021 9,404 2022 3,186 2023 2,639 2024 1,854 2025 1,852 Thereafter 2,152 Total $ 24,005

Balance Sheet Details

Balance Sheet Details	9 Months Ended
	Jul. 04, 2020
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	BALANCE SHEET DETAILS Inventories consist of the following (in thousands): July 4, September 28, Purchased parts and assemblies $ 127,885 $ 134,298 Work-in-process 178,801 174,550 Finished goods 142,286 133,682 Total inventories $ 448,972 $ 442,530 Prepaid expenses and other assets consist of the following (in thousands): July 4, September 28, Prepaid and refundable income taxes $ 56,467 $ 44,096 Other taxes receivable 9,410 11,208 Prepaid expenses and other assets 24,360 22,689 Total prepaid expenses and other assets $ 90,237 $ 77,993 Other assets consist of the following (in thousands): July 4, September 28, Assets related to deferred compensation arrangements $ 35,042 $ 35,842 Deferred tax assets 103,507 87,011 Right of use assets, net - operating leases (See Note 11) 79,640 — Right of use assets, net - finance leases (See Note 11) 723 — Other assets (1) 14,030 18,111 Total other assets $ 232,942 $ 140,964 (1) In the first quarter of fiscal 2019, we invested 3.0 million Euro ($3.4 million) in 3D-Micromac AG, a private company in Germany. The investment is included in other assets and is being carried on a cost basis and will be adjusted for impairment if we determine that indicators of impairment exist at any point in time. During the second quarter of fiscal 2020, we determined that our investment became impaired and wrote it down to its fair value. As a result, we recorded a non-cash impairment charge of $2.5 million to operating expense in our results of operations in the second quarter of fiscal 2020. Other current liabilities consist of the following (in thousands): July 4, September 28, Accrued payroll and benefits $ 53,355 $ 55,698 Operating lease liability, current (See Note 11) 13,990 — Finance lease liability, current (See Note 11) 384 — Deferred revenue 30,071 23,695 Warranty reserve 34,971 36,460 Accrued expenses and other 30,528 41,039 Customer deposits 11,258 10,843 Total other current liabilities $ 174,557 $ 167,735 Components of the reserve for warranty costs during the first nine months of fiscal 2020 and 2019 were as follows (in thousands): Nine Months Ended July 4, June 29, Beginning balance $ 36,460 $ 40,220 Additions related to current period sales 28,669 38,968 Warranty costs incurred in the current period (30,773) (41,204) Accruals resulting from acquisitions — 21 Adjustments to accruals related to foreign exchange and other 615 (453) Ending balance $ 34,971 $ 37,552 Other long-term liabilities consist of the following (in thousands): July 4, September 28, Long-term taxes payable $ 15,554 $ 37,385 Operating lease liability, long-term (See Note 11) 70,091 — Finance lease liability, long-term (See Note 11) 240 — Deferred compensation 38,704 39,715 Defined benefit plan liabilities 46,441 45,862 Deferred tax liabilities 22,312 27,785 Deferred revenue 12,727 8,012 Asset retirement obligations liability 5,418 4,934 Other long-term liabilities 4,351 2,188 Total other long-term liabilities $ 215,838 $ 165,881

Borrowings

Borrowings	9 Months Ended
	Jul. 04, 2020
Debt Disclosure [Abstract]
Borrowings	BORROWINGS On November 7, 2016 (the "Closing Date"), we entered into a Credit Agreement by and among us, Coherent Holding BV & Co. K.G. (formerly Coherent Holding GmbH), as borrower (the "Borrower"), and certain of our direct and indirect subsidiaries from time to time party thereto, as guarantors, the lenders from time to time party thereto, Barclays Bank PLC, as administrative agent and an L/C Issuer, Bank of America, N.A., as an L/C Issuer, and MUFG Union Bank, N.A., as an L/C Issuer (the "Initial Credit Agreement" and, as amended by the Amendments (defined below), the "Credit Agreement"). The Initial Credit Agreement provided for a 670.0 million Euro senior secured term loan facility (the "Euro Term Loan") and a $100.0 million senior secured revolving credit facility (the "Revolving Credit Facility") with a $30.0 million letter of credit sublimit and a $10.0 million swing line sublimit, in each case, which may be increased from time to time pursuant to an incremental feature set forth in the Credit Agreement. The Initial Credit Agreement was amended on May 8, 2017 (the "First Amendment") to reduce the interest rate margins applicable to the Euro Term Loan and was amended again on July 5, 2017 (the "Second Amendment" and, together with the First Amendment, the "Amendments") to make certain technical changes in connection with the conversion of the Borrower from a German company with limited liability to a German limited partnership. The Credit Agreement contains customary mandatory prepayment provisions. The Borrower has the right to prepay loans under the Credit Agreement in whole or in part at any time without premium or penalty, subject to customary breakage costs. Revolving loans may be borrowed, repaid and reborrowed until the fifth anniversary of the Closing Date, at which time all outstanding revolving loans must be repaid. The Euro Term Loan matures on the seventh anniversary of the Closing Date, at which time all outstanding principal and accrued and unpaid interest on the Euro Term Loan must be repaid. As of July 4, 2020, the outstanding principal amount of the Euro Term Loan was 359.9 million Euros. As of July 4, 2020, the outstanding amount of the Revolving Credit Facility was $10.0 million plus a 10.0 million Euro letter of credit. Loans under the Credit Agreement bear interest, at the Borrower’s option, at a rate equal to either (i)(x) in the case of calculations with respect to U.S. Dollars or certain other alternative currencies, the London interbank offered rate (the "LIBOR") or (y) in the case of calculations with respect to the Euro, the euro interbank offered rate ("EURIBOR" and, together with LIBOR), the "Eurocurrency Rate") or (ii) a base rate (the "Base Rate") equal to the highest of (x) the federal funds rate, plus 0.50%, (y) the prime rate then in effect and (z) the Eurocurrency Rate for loans denominated in U.S. dollars applicable to a one-month interest period, plus 1.0%, in each case, plus an applicable margin that is subject to adjustment pursuant to a pricing grid based on consolidated total gross leverage ratio. At July 4, 2020, the applicable margin for Euro Term Loans borrowed as Eurocurrency Rate loans was 2.25% per annum and as Base Rate loans was 1.25%. The applicable margin for revolving loans borrowed as Eurocurrency Rate loans was 4.00% per annum and as Base Rate loans was 3.00% per annum. Interest on Base Rate Loans is payable quarterly in arrears. Interest on Eurocurrency Rate loans is payable at the end of the applicable interest period (or at three month intervals if the interest period exceeds three months). The Credit Agreement requires the Borrower to make scheduled quarterly payments on the Euro Term Loan of 0.25% of the original principal amount of the Euro Term Loan, with any remaining principal payable at maturity. A commitment fee accrues on any unused portion of the revolving loan commitments under the Credit Agreement at a rate of 0.375% or 0.5% depending on the consolidated total gross leverage ratio at any time of determination. The Borrower is also obligated to pay other customary fees for a credit facility of this size and type. On the Closing Date, we and certain of our direct and indirect subsidiaries, as guarantors, provided an unconditional guaranty of all obligations of the Borrower and the other loan parties arising under the Credit Agreement, the other loan documents and under swap contracts and treasury management agreements with the lenders or their affiliates (with certain limited exceptions). The Borrower and the guarantors have also granted security interests in substantially all of their assets to secure such obligations. The Credit Agreement contains customary affirmative and negative covenants, including covenants limiting the ability of us and our subsidiaries to, among other things, incur debt, grant liens, make investments, make certain restricted payments, transact with affiliates, and sell assets. The Credit Agreement also requires us and our subsidiaries to maintain a senior secured net leverage ratio as of the last day of each fiscal quarter of less of than or equal to 3.50 to 1.00. We were in compliance with all covenants at July 4, 2020. We incurred $28.5 million of debt issuance costs related to the Euro Term Loan and $0.5 million of debt issuance costs to the original lenders related to the First Amendment, which are included in short-term borrowings and current portion of long-term obligations and long-term obligations in the condensed consolidated balance sheets and will be amortized to interest expense over the seven year life of the Euro Term Loan using the effective interest method, adjusted to accelerate amortization related to voluntary repayments. We incurred $2.3 million of debt issuance costs in connection with the Revolving Credit Facility which were capitalized and included in prepaid expenses and other assets in the condensed consolidated balance sheets and will be amortized to interest expense using the straight-line method over the contractual term of five years of the Revolving Credit Facility. Additional sources of cash available to us were international currency lines of credit and bank credit facilities totaling $16.4 million as of July 4, 2020, of which $13.5 million was unused and available. These unsecured international credit facilities were used in Europe and Japan during the first nine months of fiscal 2020. As of July 4, 2020, we had utilized $2.9 million of the international credit facilities as guarantees in Europe. Short-term borrowings and current portion of long-term obligations consist of the following (in thousands): July 4, September 28, Current portion of Euro Term Loan (1) $ 4,764 $ 2,748 1.3% Term loan due 2024 1,410 1,367 1.0% State of Connecticut term loan due 2023 380 378 Capital lease obligations — 370 Line of credit borrowings 10,000 10,000 Total short-term borrowings and current portion of long-term obligations $ 16,554 $ 14,863 (1) Net of debt issuance costs of $2.8 million and $4.6 million at July 4, 2020 and September 28, 2019, respectively. Long-term obligations consist of the following (in thousands): July 4, September 28, Euro Term Loan due 2024 (1) $ 391,940 $ 385,208 1.3% Term loan due 2024 4,582 5,466 1.0% State of Connecticut term loan due 2023 742 1,028 Capital lease obligations — 536 Total long-term obligations $ 397,264 $ 392,238 (1) Net of debt issuance costs of $6.4 million and $6.4 million at July 4, 2020 and September 28, 2019, respectively. Contractual maturities of our debt obligations, excluding line of credit borrowings, as of July 4, 2020 are as follows (in thousands): Amount 2020 (remainder) $ 2,428 2021 9,338 2022 9,338 2023 9,159 2024 382,719 Total $ 412,982

Leases

Leases	9 Months Ended
	Jul. 04, 2020
Leases [Abstract]
LEASES	LEASES We determine if an arrangement contains a lease at inception for arrangements with an initial term of more than 12 months, and classify it as either a finance or operating lease. We lease certain real and personal property from unrelated third parties under non-cancellable operating leases that expire at various dates through fiscal 2032. 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 assume renewals in our determination of the lease term when 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 three to six years. Our assets, liabilities and lease costs related to finance leases are immaterial. As the rates implicit in our leases are not readily determinable, we use incremental borrowing rates based on the information available at the commencement date in determining the present value of future lease payments. We consider both the credit rating and the length of the lease when calculating the incremental borrowing rate. We combine lease and non-lease components into a single lease component for both our operating and finance leases. 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. We generally recognize sublease income on a straight-line basis over the sublease term. As a result of interim impairment testing performed on long-lived assets in the quarter ended April 4, 2020, we recorded non-cash pre-tax charges related to the ROU assets of the ILS reporting unit of $1.8 million in the quarter ended April 4, 2020. See Note 8, "Goodwill and Intangible Assets" for discussion of the interim impairment testing. The components of operating lease costs (in thousands), lease term (in years) and discount rate are as follows: Three Months Ended Nine Months Ended July 4, 2020 July 4, 2020 Operating lease cost $ 4,907 $ 14,875 Variable lease cost 348 1,036 Short-term lease cost 123 383 Sublease income (32) (96) Total lease cost $ 5,346 $ 16,198 July 4, 2020 Weighted average remaining lease term 8.1 Weighted average discount rate 4.9 % Supplemental cash flow information related to leases are as follows (in thousands): Nine Months Ended July 4, 2020 Operating cash outflows from operating leases $ 14,672 ROU assets obtained in exchange for new operating lease liabilities 2,746 See Note 9, "Balance Sheet Details" for supplemental balance sheet information related to leases. As of July 4, 2020, maturities of our operating lease liabilities, which do not include short-term leases and variable lease payments, are as follows (in thousands): Operating Leases 2020 (remainder) $ 3,788 2021 17,582 2022 15,871 2023 12,632 2024 10,128 2025 and thereafter 45,631 Total minimum lease payments 105,632 Amounts representing interest (21,575) Present value of total lease liabilities $ 84,057 As of September 28, 2019, future minimum lease payments as defined under the previous lease accounting guidance of ASC 840 under non-cancellable operating leases were as follows (in thousands): Operating Leases 2020 $ 19,578 2021 14,579 2022 10,405 2023 6,817 2024 4,156 2025 and thereafter 10,755 Total minimum lease payments $ 66,290
LEASES	LEASES We determine if an arrangement contains a lease at inception for arrangements with an initial term of more than 12 months, and classify it as either a finance or operating lease. We lease certain real and personal property from unrelated third parties under non-cancellable operating leases that expire at various dates through fiscal 2032. 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 assume renewals in our determination of the lease term when 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 three to six years. Our assets, liabilities and lease costs related to finance leases are immaterial. As the rates implicit in our leases are not readily determinable, we use incremental borrowing rates based on the information available at the commencement date in determining the present value of future lease payments. We consider both the credit rating and the length of the lease when calculating the incremental borrowing rate. We combine lease and non-lease components into a single lease component for both our operating and finance leases. 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. We generally recognize sublease income on a straight-line basis over the sublease term. As a result of interim impairment testing performed on long-lived assets in the quarter ended April 4, 2020, we recorded non-cash pre-tax charges related to the ROU assets of the ILS reporting unit of $1.8 million in the quarter ended April 4, 2020. See Note 8, "Goodwill and Intangible Assets" for discussion of the interim impairment testing. The components of operating lease costs (in thousands), lease term (in years) and discount rate are as follows: Three Months Ended Nine Months Ended July 4, 2020 July 4, 2020 Operating lease cost $ 4,907 $ 14,875 Variable lease cost 348 1,036 Short-term lease cost 123 383 Sublease income (32) (96) Total lease cost $ 5,346 $ 16,198 July 4, 2020 Weighted average remaining lease term 8.1 Weighted average discount rate 4.9 % Supplemental cash flow information related to leases are as follows (in thousands): Nine Months Ended July 4, 2020 Operating cash outflows from operating leases $ 14,672 ROU assets obtained in exchange for new operating lease liabilities 2,746 See Note 9, "Balance Sheet Details" for supplemental balance sheet information related to leases. As of July 4, 2020, maturities of our operating lease liabilities, which do not include short-term leases and variable lease payments, are as follows (in thousands): Operating Leases 2020 (remainder) $ 3,788 2021 17,582 2022 15,871 2023 12,632 2024 10,128 2025 and thereafter 45,631 Total minimum lease payments 105,632 Amounts representing interest (21,575) Present value of total lease liabilities $ 84,057 As of September 28, 2019, future minimum lease payments as defined under the previous lease accounting guidance of ASC 840 under non-cancellable operating leases were as follows (in thousands): Operating Leases 2020 $ 19,578 2021 14,579 2022 10,405 2023 6,817 2024 4,156 2025 and thereafter 10,755 Total minimum lease payments $ 66,290

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Jul. 04, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION Fair Value of Stock Compensation We recognize compensation expense for all share-based payment awards based on the fair value of such awards. The expense is recognized on a straight-line basis per tranche over the respective requisite service period of the awards. Determining Fair Value The fair values of shares purchased under the Employee Stock Purchase Plan ("ESPP") for the three and nine months ended July 4, 2020 and June 29, 2019, respectively, were estimated using the following weighted-average assumptions: Employee Stock Purchase Plan Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Expected life in years 0.5 0.5 0.5 0.5 Volatility 63.7 % 47.9 % 53.0 % 47.9 % Risk-free interest rate 0.54 % 2.46 % 1.27 % 2.43 % Expected dividend yield — % — % — % — % Weighted average fair value per share $ 43.35 $ 40.42 $ 43.81 $ 40.57 We grant performance restricted stock units to officers and certain employees. The performance restricted stock unit agreements provide for the award of performance units with each unit representing the right to receive one share of our common stock to be issued after the applicable award vesting period. The final number of units awarded, if any, for these performance grants will be determined as of the vesting dates, based upon our total shareholder return over the performance period compared to the applicable Russell Index and could range from no units to a maximum of twice the initial award units. The weighted average fair value for the performance units granted for the nine months ended July 4, 2020 and June 29, 2019 was determined using a Monte Carlo simulation model incorporating the following weighted average assumptions: Nine Months Ended Nine Months Ended July 4, June 29, Risk-free interest rate 0.9 % 2.9 % Volatility 50.4 % 43.7 % Weighted average fair value per share $ 162.14 $ 117.43 We recognize the estimated cost of these awards, as determined under the simulation model, over the related service period of approximately 3 years, with no adjustment in future periods based upon the actual shareholder return over the performance period. In addition, in the three months ended July 4, 2020, we issued performance units to certain employees with vesting based on goals related to free cash flow target amounts, with the initial fair value determined based on our closing stock price on the date of grant. Such awards were granted to serve as a performance incentive with a pay-for-performance forward-looking free cash flow target for the fiscal year in recognition of the impact of the COVID-19 pandemic. The number of shares issuable under these performance units upon satisfaction of the free cash flow performance criteria is capped at 100% of target. The total stock-based compensation of these awards will be adjusted based on the level of achievement of free cash flow. Stock Compensation Expense The following table shows total stock-based compensation expense and related tax benefits included in the condensed consolidated statements of operations for the three and nine months ended July 4, 2020 and June 29, 2019 (in thousands): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Cost of sales $ 1,237 $ 1,231 $ 3,430 $ 3,640 Research and development 1,469 794 2,924 2,227 Selling, general and administrative 11,680 7,630 24,722 20,668 Income tax benefit (1,552) (1,412) (3,414) (4,106) $ 12,834 $ 8,243 $ 27,662 $ 22,429 During the three and nine months ended July 4, 2020, stock-based compensation expense includes $3.5 million related to acceleration of stock-based compensation as a result of our former CEO's transition from CEO to Special Advisor to the company as of April 6, 2020. During the three and nine months ended July 4, 2020, $2.1 million and $4.3 million of stock-based compensation cost, respectively, were capitalized as part of inventory for all stock plans, $1.2 million and $3.4 million, respectively, were amortized into cost of sales and $2.4 million remained in inventory at July 4, 2020. During the three and nine months ended June 29, 2019, $1.2 million and $3.6 million of stock-based compensation cost, respectively, was capitalized as part of inventory for all stock plans, $1.2 million and $3.6 million, respectively, were amortized into cost of sales and $1.5 million remained in inventory at June 29, 2019. At July 4, 2020, the total compensation cost related to unvested stock-based awards granted to employees under our stock plans but not yet recognized was approximately $49.5 million. We do not estimate forfeitures. This cost will be amortized on a straight-line basis over a weighted-average period of approximately 1.4 years. Stock Awards Activity The following table summarizes the activity of our time-based and performance-based restricted stock units for the first nine months of fiscal 2020 (in thousands, except per share amounts): Time-based Restricted Stock Units Performance-based Restricted Stock Units Number of Weighted Number of Weighted Nonvested stock at September 28, 2019 295 $ 152.47 133 $ 184.26 Granted 277 141.57 82 153.22 Vested (1) (149) 150.71 (81) 163.17 Forfeited (9) 174.40 — — Nonvested stock at July 4, 2020 414 $ 145.35 134 $ 178.08

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jul. 04, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	COMMITMENTS AND CONTINGENCIES 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 July 4, 2020, we did not have any material indemnification claims that were probable or reasonably possible. Legal Proceedings We are subject to claims and litigation arising in the ordinary course of business, such as contract-related, product sales and servicing, real estate, product liability, regulatory matters, employment or intellectual property claims. Although we do not expect that such claims and litigation will ultimately have a material adverse effect on our consolidated financial position, results of operations or cash flows, an adverse result in one or more matters could negatively affect our results in the period in which they occur, or in future periods. The United States and many foreign governments impose tariffs and duties on the import and export of certain products we sell. From time to time our customs compliance, product classifications, duty calculations and payments are reviewed or audited by government agencies. Any adverse result in such a review or audit could negatively affect our results in the period in which they occur, or in future periods. German authorities are currently investigating an export compliance matter involving one of our German subsidiaries involving four former employees (whose employment was terminated following our discovery of this matter). While under German law the subsidiary can be held liable for certain infringements by its employees of German export control laws, we believe that this matter involves less than approximately 1.5 million Euros in transactions in the period currently under investigation and do not believe that the final resolution of this matter will be material to our consolidated financial position, results of operations or cash flows. However, the German government investigation is ongoing and it is possible that substantial payments, fines, penalties or damages could result. Even though we do not currently expect this matter to be material to our consolidated financial position, results of operations or cash flows, circumstances could change as the investigation progresses.

Stock Repurchases

Stock Repurchases	9 Months Ended
	Jul. 04, 2020
Stock Repurchase [Abstract]
Stock Repurchases	STOCK REPURCHASES On October 28, 2018, our board of directors authorized a stock repurchase program authorizing the Company to repurchase up to $250.0 million of our common stock through December 31, 2019, with a limit of no more than $75.0 million per quarter. During fiscal 2019, we repurchased and retired 603,828 shares of outstanding common stock under this program at an average price of $128.20 per share for a total of $77.4 million. We made no repurchases under the program during fiscal 2020 and the program expired on December 31, 2019. On February 5, 2020, our board of directors authorized a stock repurchase program authorizing the Company to repurchase up to $100.0 million of our common stock through January 31, 2021.We made no repurchases under the program through July 4, 2020.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Jul. 04, 2020
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE Basic earnings per share is computed based on the weighted average number of shares outstanding during the period, excluding unvested restricted stock. Diluted earnings per share is computed based on the weighted average number of shares outstanding during the period increased by the effect of dilutive employee stock awards, including stock options, restricted stock awards and stock purchase plan contracts, using the treasury stock method. The following table presents information necessary to calculate basic and diluted earnings per share (in thousands, except per share data): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Weighted average shares outstanding—basic 24,159 24,054 24,075 24,185 Dilutive effect of employee stock awards — — — 148 Weighted average shares outstanding—diluted 24,159 24,054 24,075 24,333 Net income (loss) $ (8,708) $ (3,099) $ (421,828) $ 53,201 For the three and nine months ended July 4, 2020, all potentially dilutive securities have been excluded from the from the diluted share calculation as we reported a net loss.

Other Income (Expense)

Other Income (Expense)	9 Months Ended
	Jul. 04, 2020
Other Income and Expenses [Abstract]
Other Income (Expense)	OTHER INCOME (EXPENSE) Other income (expense) is as follows (in thousands): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Foreign exchange loss $ (1,623) $ (518) $ (3,316) $ (5,066) Gain (loss) on deferred compensation investments, net 619 (6) 1,426 (947) Other 499 855 568 2,115 Other—net $ (505) $ 331 $ (1,322) $ (3,898)

Income Taxes

Income Taxes	9 Months Ended
	Jul. 04, 2020
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income tax expense includes a provision for federal, state and foreign taxes based on the annual estimated effective tax rate applicable to us and our subsidiaries, adjusted for items which are considered discrete to the period. On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security Act (the "CARES Act") was enacted and signed into law. U.S. GAAP rules require recognition of the tax effects of new legislation during the reporting period that includes the enactment date. The CARES Act, among other things, includes tax provision changes that benefit business entities and it makes certain technical corrections to the Tax Act. The tax relief measures for business include a five-year net operating loss (“NOL”) carryback, suspension of the annual deduction limitation for net operating losses generated in a tax year beginning after December 31, 2017, changes in the deductibility of interest, acceleration of alternative minimum tax credit refunds, payroll tax relief, and technical corrections allowing accelerated deductions for qualified improvement property. The CARES Act also provides other non-tax benefits, including employee retention credits, to assist businesses impacted by the pandemic. We are currently evaluating the income tax benefits of the CARES Act. Our effective tax rate on loss before income taxes for the three and nine months ended July 4, 2020 reflected a provision at a 59.6% rate and a benefit at a 6.9% rate, respectively. Our effective tax rate for the three months ended July 4, 2020 was unfavorably impacted primarily due to the establishment of valuation allowances for certain deferred tax assets. Our effective tax rate for the nine months ended July 4, 2020 was unfavorably impacted primarily due to the impairment of goodwill that is not deductible for tax purposes and the establishment of valuation allowances for certain deferred tax assets. These unfavorable impacts were partially offset by the release of unrecognized tax benefits net of settlements and competent authority offsets, the geographic distribution of the impairments of certain long-lived assets that are deductible for tax purposes and the reduction in foreign earnings subject to foreign tax rates that are higher than the U.S. tax rates. Our effective tax rate is based on forecasted annual results and these amounts may fluctuate significantly through the rest of the year as a result of the unpredictable impact of COVID-19 on our operating activities. Our effective tax rate on income (loss) before income taxes for the three and nine months ended June 29, 2019 was a benefit at a 73.2% rate and a provision at a 6.2% rate, respectively. Our effective tax rate for the three months ended June 29, 2019 reflected the recognition of a tax benefit on a pre-tax loss. This loss was in part a result of the restructuring costs in the third quarter of fiscal 2019 in our German operations resulting from our decision to relocate the manufacturing and engineering of our High Power Fiber Lasers ("HPFL") products at our Hamburg, Germany facility to our Tampere, Finland location and exit a portion of our HPFL business. A benefit in a high tax jurisdiction increases the effective tax rate on a loss. Furthermore, revision of the estimated annual effective tax rate in the three months ended June 29, 2019 resulted in additional benefit to the period and cumulatively offset tax expense recorded through the previous quarter. Our effective tax rate for the nine months ended June 29, 2019 was lower than the U.S. federal tax rate of 21.0% primarily due to the tax benefit from German losses subject to higher tax rates than U.S. tax rates, the excess tax benefits from restricted stock unit vesting, the benefit of federal research and development tax credits and our Singapore and South Korea tax exemptions. These amounts were partially offset by an accrual for foreign withholding taxes on certain current year foreign earnings not considered permanently reinvested, stock-based compensation not deductible for tax purposes and limitations on the deductibility of compensation under IRC Section 162(m). The following table summarizes the activity related to our gross unrecognized tax benefits for the nine months ended July 4, 2020 (amounts in thousands): Nine Months Ended July 4, Balance as of the beginning of the year $ 58,111 Increases related to acquisitions — Tax positions related to current year: Additions 1,238 Reductions — Tax positions related to prior year: Additions — Reductions — Settlements — Lapses in statutes of limitations (681) Decrease in unrecognized tax benefits based on tax audit results (19,463) Foreign currency revaluation adjustment 247 Balance as of end of period $ 39,452

Defined Benefit Plans

Defined Benefit Plans	9 Months Ended
	Jul. 04, 2020
Postemployment Benefits [Abstract]
Defined Benefits Plans	DEFINED BENEFIT PLANS For the three and nine months ended July 4, 2020, net periodic cost under our defined benefit plans was $0.6 million and $1.4 million, respectively. For the three and nine months ended June 29, 2019, net periodic cost (benefit) under our defined benefit plans was a benefit of $0.4 million and $0.2 million, respectively. The service cost component of net periodic costs is included in selling, general and administrative ("SG&A") expenses, and the interest costs, net actuarial (gain) loss and other components are included in Other—net in the condensed consolidated statements of operations.

Segment and Geographic Informat

Segment and Geographic Information	9 Months Ended
	Jul. 04, 2020
Segment Reporting [Abstract]
Segment and Geographic Information	SEGMENT AND GEOGRAPHIC INFORMATIONAt July 4, 2020, we were organized into two reporting segments, OEM Laser Sources ("OLS") and Industrial Lasers & Systems ("ILS"), based upon our organizational structure and how the CODM receives and utilizes information provided to allocate resources and make decisions. This segmentation reflects the go-to-market strategies and synergies for our broad portfolio of laser technologies and products. While both segments deliver cost-effective, highly reliable photonics solutions, the OLS business segment is focused on high performance laser sources and complex optical sub-systems, typically used in microelectronics manufacturing, medical diagnostics and therapeutic applications, as well as in scientific research. Our ILS business segment delivers high performance laser sources, sub-systems and tools primarily used for industrial laser materials processing, serving important end markets like automotive, machine tool, consumer goods and medical device manufacturing. We have identified OLS and ILS as operating segments for which discrete financial information is available. Both units have dedicated engineering, manufacturing, product business management and product line management functions. A small portion of our outside revenue is attributable to projects and recently developed products for which a segment has not yet been determined. The associated direct and indirect costs are presented in the category of Corporate and other, along with other corporate costs as described below. Our Chief Executive Officer has been identified as the CODM, as he assesses the performance of the segments and decides how to allocate resources to the segments. Income from operations is the measure of profit and loss that our CODM uses to assess performance and make decisions. Assets by segment are not a measure used to assess the performance of the company by the CODM and thus are not reported in our disclosures. Income from operations represents the net sales less the cost of sales and direct operating expenses incurred within the operating segments as well as allocated expenses such as shared sales and manufacturing costs. We do not allocate certain operating expenses to our operating segments and we manage them at the corporate level. These unallocated costs include stock-based compensation and corporate functions (certain research and development, management, finance, legal and human resources) and are included in the results below under Corporate and other in the reconciliation of operating results. Management does not consider unallocated Corporate and other costs in its measurement of segment performance. The following table provides net sales and income (loss) from operations for our operating segments and a reconciliation of our total income (loss) from operations to income (loss) before income taxes (in thousands): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Net sales: OEM Laser Sources $ 184,694 $ 206,285 $ 559,364 $ 680,230 Industrial Lasers & Systems 113,636 132,885 352,884 414,946 Total net sales $ 298,330 $ 339,170 $ 912,248 $ 1,095,176 Income (loss) from operations: OEM Laser Sources $ 42,853 $ 48,310 $ 126,030 $ 190,003 Industrial Lasers & Systems (20,571) (39,569) (512,716) (70,925) Corporate and other (23,456) (15,898) (53,209) (44,557) Total income (loss) from operations (1,174) (7,157) (439,895) 74,521 Total other expense, net (4,282) (4,386) (12,979) (17,789) Income (loss) before income taxes $ (5,456) $ (11,543) $ (452,874) $ 56,732 Geographic Information Our foreign operations consist primarily of manufacturing facilities and sales offices in Europe and Asia-Pacific. Sales, marketing and customer service activities are conducted through sales subsidiaries throughout the world. Geographic sales information for the three and nine months ended July 4, 2020 and June 29, 2019 is based on the location of the end customer. Sales to unaffiliated customers are as follows (in thousands): Three Months Ended Nine Months Ended SALES July 4, June 29, July 4, June 29, United States $ 65,094 $ 82,913 $ 215,236 $ 251,122 Foreign countries: South Korea 63,428 65,717 180,412 235,443 China 52,837 57,519 148,407 152,134 Japan 22,272 24,119 70,990 114,702 Asia-Pacific, other 24,090 23,954 67,889 72,100 Germany 28,650 32,809 90,485 111,646 Europe, other 27,917 38,296 95,130 114,973 Rest of World 14,042 13,843 43,699 43,056 Total foreign countries sales 233,236 256,257 697,012 844,054 Total sales $ 298,330 $ 339,170 $ 912,248 $ 1,095,176 Major Customers We had one customer during the three and nine months ended July 4, 2020 that accounted for 17.1% and 16.7% of net sales, respectively. This same customer accounted for 15.6% and 15.9% of net sales during the three and nine months ended June 29, 2019, respectively. This customer purchased primarily from our OLS segment.

Restructuring Charges

Restructuring Charges	9 Months Ended
	Jul. 04, 2020
Restructuring and Related Activities [Abstract]
Restructuring charges	RESTRUCTURING CHARGES In the first quarter of fiscal 2017, we began the implementation of planned restructuring activities in connection with the acquisition of Rofin. The activities under this plan primarily related to the exiting of our legacy HPFL product line, change of control payments to Rofin officers, the exiting of two product lines acquired in the acquisition of Rofin, realignment of our supply chain due to segment reorganization and consolidation of sales and distribution offices as well as certain manufacturing sites. These activities resulted in charges primarily for employee termination, other exit related costs associated with the write-off of property and equipment and inventory and early lease termination costs. In June 2019, we announced our plans to co-locate the manufacturing and engineering of our HPFL products at our Hamburg, Germany facility to our Tampere, Finland location and exit a portion of our HPFL business. In conjunction with this announcement, we recorded charges in the third quarter of fiscal 2019 of $20.9 million primarily related to write-offs of excess inventory, which is recorded in cost of sales, and estimated severance. We recorded charges in the first, second and third quarters of fiscal 2020 of $0.6 million, $0.5 million and $0.1 million, respectively, primarily related to accelerated depreciation and project management consulting. We have also announced our intent to vacate our leased facility in Santa Clara at the end of the current lease term in calendar 2020 and combine operations at our Santa Clara headquarters. We exited this facility on July 31, 2020. We did not incur material expenses in fiscal 2019 related to this project. We incurred costs in the first, second and third quarters of fiscal 2020 of $0.2 million, $0.6 million and $0.4 million, respectively, related to this project. We also incurred costs in the first quarter of fiscal 2020 of $0.1 million for other projects. The following table presents our current liability as accrued on our balance sheets for restructuring charges. The table sets forth an analysis of the components of the restructuring charges and payments and other deductions made against the accrual for the quarters of fiscal 2020 and 2019 (in thousands): Severance Related Asset Write-Offs Other Total Balances, September 28, 2019 $ 8,279 $ — $ 215 $ 8,494 Provision 54 599 280 933 Payments and other (658) (599) (275) (1,532) Balances, December 28, 2019 7,675 — 220 7,895 Provision 85 915 79 1,079 Payments and other (3,715) (915) (87) (4,717) Balances, April 4, 2020 4,045 — 212 4,257 Provision (77) 554 41 518 Payments and other (3,136) (554) (31) (3,721) Balances, July 4, 2020 $ 832 $ — $ 222 $ 1,054 Severance Related Asset Write-Offs Other Total Balances, September 29, 2018 $ 836 $ — $ 286 $ 1,122 Provision 212 76 188 476 Payments and other (447) (76) (244) (767) Balances, December 29, 2018 601 — 230 831 Provision 282 247 351 880 Payments and other (201) (247) (516) (964) Balances, March 30, 2019 682 — 65 747 Provision 9,338 11,798 137 21,273 Payments and other 19 (11,798) (34) (11,813) Balances, June 29, 2019 $ 10,039 $ — $ 168 $ 10,207 At July 4, 2020, $1.1 million of accrued severance related and other costs were included in other current liabilities. The asset write-offs for accelerated depreciation and other costs in the first, second and third quarters of fiscal 2020 primarily related to the exit of a portion of our HPFL business in Hamburg, Germany, and costs to vacate our leased facility in Santa Clara and combine operations at our Santa Clara headquarters. The severance related, asset write-offs of inventory and other costs in the first nine months of fiscal 2019 primarily related to the exit of a portion of our HPFL business in Hamburg, Germany. By segment, $0.1 million and $1.3 million of restructuring costs were incurred in the ILS segment and $0.4 million and $1.2 million were incurred in the OLS segment in the three and nine months ended July 4, 2020, respectively. In the three and nine months ended June 29, 2019, all of the restructuring costs were incurred in the ILS segment and none were incurred in the OLS segment. Restructuring charges are recorded in cost of sales, research and development and selling, general and administrative expenses in our condensed consolidated statements of operations.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Jul. 04, 2020
Revenue from Contract with Customer [Abstract]
Summary of Revenue from Contracts with Customers	The following tables summarize revenue from contracts with customers (in thousands): Sales by revenue type and segment Three Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 109,995 $ 91,114 $ 115,992 $ 104,784 Other product and service revenues (2) 74,699 22,522 90,293 28,101 Total net sales $ 184,694 $ 113,636 $ 206,285 $ 132,885 (1) Net sales primarily recognized at a point in time. (2) Includes sales of spare parts, related accessories and other consumable parts as well as revenues from service agreements, of which $15.4 million and $14.1 million for the three months ended July 4, 2020 and June 29, 2019, respectively, were recognized over time. Nine Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 321,691 $ 277,710 $ 412,629 $ 329,537 Other product and service revenues (2) 237,673 75,174 267,601 85,409 Total net sales $ 559,364 $ 352,884 $ 680,230 $ 414,946 (1) Net sales primarily recognized at a point in time. (2) Includes sales of spare parts, related accessories and other consumable parts as well as revenues from service agreements, of which $46.3 million and $40.1 million for the nine months ended July 4, 2020 and June 29, 2019, respectively, were recognized over time. Sales by market application and segment Three Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 123,635 $ 18,207 $ 126,754 $ 16,467 Materials processing 7,581 74,156 11,207 90,198 OEM components and instrumentation 33,588 19,903 39,997 24,300 Scientific and government programs 19,890 1,370 28,327 1,920 Total net sales $ 184,694 $ 113,636 $ 206,285 $ 132,885 Nine Months Ended July 4, 2020 June 29, 2019 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 343,429 $ 50,726 $ 441,597 $ 49,298 Materials processing 26,373 230,043 29,493 281,477 OEM components and instrumentation 120,502 65,903 119,027 78,825 Scientific and government programs 69,060 6,212 90,113 5,346 Total net sales $ 559,364 $ 352,884 $ 680,230 $ 414,946
Summary of Customer Deposits and Deferred Revenue	A rollforward of our customer deposits and deferred revenue is as follows (in thousands): Beginning balance, September 28, 2019 (1) $ 42,550 Additions to customer deposits and deferred revenue 137,747 Amount of customer deposits and deferred revenue recognized in income (2) (126,501) Translation adjustments 260 Ending balance, July 4, 2020 (3) $ 54,056 (1) Beginning customer deposits and deferred revenue as of September 28, 2019 include $34,538 of current portion and $8,012 of long-term portion. (2) Amount of customer deposits and deferred revenue recognized in the three months ended July 4, 2020 was $48,674.
Summary of Estimated Revenue Expected to be Recognized in the Future	The following table includes estimated revenue expected to be recognized in the future related to performance obligations for sales of maintenance agreements, extended warranties, installation, and contracts with customer acceptance provisions included in customer deposits and deferred revenue as of July 4, 2020 (in thousands): Remainder of fiscal 2020 Thereafter Total Performance obligations as of July 4, 2020 $ 27,120 $ 26,936 $ 54,056

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Jul. 04, 2020
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	Our allocation of the purchase price is as follows (in thousands): Tangible assets: Cash $ 103 Accounts receivable 534 Inventories 1,793 Prepaid expenses and other assets 17 Deferred tax assets 681 Property and equipment 122 Liabilities assumed (499) Intangible assets: Existing technology 5,600 Customer relationships 300 Goodwill 3,333 Total $ 11,984 Our allocation of the purchase price is as follows (in thousands): Tangible assets: Property and equipment $ 2,770 Intangible assets: Existing technology 1,600 Customer relationships 230 Production know-how 2,300 Backlog 100 Total $ 7,000

Fair Values (Tables)

Fair Values (Tables)	9 Months Ended
	Jul. 04, 2020
Fair Value Disclosures [Abstract]
Schedule of financial assets and liabilities measured at fair value	Financial assets and liabilities measured at fair value as of July 4, 2020 and September 28, 2019 are summarized below (in thousands): Aggregate Fair Value Quoted Prices Significant Aggregate Fair Value Quoted Prices Significant July 4, 2020 September 28, 2019 (Level 1) (Level 2) (Level 1) (Level 2) Assets: Cash equivalents: Money market fund deposits $ 59,052 $ 59,052 $ — $ 21,422 $ 21,422 $ — Certificates of deposit 13,200 13,200 — — — — Short-term investments: U.S. Treasury and agency obligations (1) 115 — 115 120 — 120 Certificates of deposit 41,783 41,783 — — — — Prepaid and other assets: Foreign currency contracts (2) 589 — 589 370 — 370 Money market fund deposits — Deferred comp and supplemental plan (3) 193 193 — 433 433 — Mutual funds — Deferred comp and supplemental plan (3) 19,941 19,941 — 22,419 22,419 — Total $ 134,873 $ 134,169 $ 704 $ 44,764 $ 44,274 $ 490 Liabilities: Other current liabilities: Foreign currency contracts (2) (845) — (845) (960) — (960) Total $ 134,028 $ 134,169 $ (141) $ 43,804 $ 44,274 $ (470) ___________________________________________________ (1) Valuations are based upon quoted market prices in active markets involving similar assets. The market inputs used to value these instruments generally consist of market yields, reported trades, broker/dealer quotes or alternative pricing sources with reasonable levels of price transparency. Pricing sources include industry standard data providers, security master files from large financial institutions, and other third party sources which are input into a distribution-curve-based algorithm to determine a daily market value. This creates a "consensus price" or a weighted average price for each security. (2) The principal market in which we execute our foreign currency contracts is the institutional market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large commercial banks. Our foreign currency contracts’ valuation inputs are based on quoted prices and quoted pricing intervals from public data sources and do not involve management judgment. See Note 7, "Derivative Instruments and Hedging Activities."

Short-Term Investments (Tables)

Short-Term Investments (Tables)	9 Months Ended
	Jul. 04, 2020
Cash, Cash Equivalents, and Short-term Investments [Abstract]
Schedule of Cash, Cash Equivalents and Short-Term Investments	Cash, cash equivalents and short-term investments consist of the following (in thousands): July 4, 2020 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 378,992 $ — $ — $ 378,992 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 115 $ — $ — $ 115 Certificates of deposit 41,783 — — 41,783 Total short-term investments $ 41,898 $ — $ — $ 41,898 September 28, 2019 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 305,833 $ — $ — $ 305,833 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 120 $ — $ — $ 120 Total short-term investments $ 120 $ — $ — $ 120

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Jul. 04, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Notional Amounts of Outstanding Derivative Positions	The total outstanding notional contract and fair value asset (liability) amounts of non-designated hedge contracts, with maximum maturity of two months, are as follows (in thousands): U.S. Notional Contract Value U.S. Fair Value July 4, 2020 September 28, 2019 July 4, 2020 September 28, 2019 Foreign currency hedge contracts Purchase $ 70,682 $ 53,920 $ 464 $ (117) Sell $ (86,375) $ (86,984) $ (720) $ (473)

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Jul. 04, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill by segment for the period from September 28, 2019 to July 4, 2020 are as follows (in thousands): OEM Laser Sources Industrial Lasers & Systems Total Balance as of September 28, 2019 $ 96,820 $ 330,281 $ 427,101 Impairment charges — (327,203) (327,203) Translation adjustments 1,827 (3,078) (1,251) Balance as of July 4, 2020 $ 98,647 $ — $ 98,647
Schedule of Components of Amortizable Intangible Assets	Components of our amortizable intangible assets are as follows (in thousands): July 4, 2020 September 28, 2019 Gross Accumulated Net Gross Accumulated Net Existing technology $ 43,114 $ (32,181) $ 10,933 $ 193,704 $ (131,429) $ 62,275 Customer relationships 24,076 (12,503) 11,573 42,083 (21,512) 20,571 Trade name — — — 5,261 (5,138) 123 Production know-how 2,300 (801) 1,499 2,300 (456) 1,844 Total $ 69,490 $ (45,485) $ 24,005 $ 243,348 $ (158,535) $ 84,813
Schedule of Estimated Amortization Expense	At July 4, 2020, estimated amortization expense for the remainder of fiscal 2020, the next five succeeding fiscal years and all fiscal years thereafter are as follows (in thousands): Estimated Amortization 2020 (remainder) $ 2,918 2021 9,404 2022 3,186 2023 2,639 2024 1,854 2025 1,852 Thereafter 2,152 Total $ 24,005

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	9 Months Ended
	Jul. 04, 2020
Balance Sheet Related Disclosures [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands): July 4, September 28, Purchased parts and assemblies $ 127,885 $ 134,298 Work-in-process 178,801 174,550 Finished goods 142,286 133,682 Total inventories $ 448,972 $ 442,530
Schedule of Prepaid Expenses and Other Assets	Prepaid expenses and other assets consist of the following (in thousands): July 4, September 28, Prepaid and refundable income taxes $ 56,467 $ 44,096 Other taxes receivable 9,410 11,208 Prepaid expenses and other assets 24,360 22,689 Total prepaid expenses and other assets $ 90,237 $ 77,993
Schedule of Other Assets	Other assets consist of the following (in thousands): July 4, September 28, Assets related to deferred compensation arrangements $ 35,042 $ 35,842 Deferred tax assets 103,507 87,011 Right of use assets, net - operating leases (See Note 11) 79,640 — Right of use assets, net - finance leases (See Note 11) 723 — Other assets (1) 14,030 18,111 Total other assets $ 232,942 $ 140,964
Schedule of Other Current Liabilities	Other current liabilities consist of the following (in thousands): July 4, September 28, Accrued payroll and benefits $ 53,355 $ 55,698 Operating lease liability, current (See Note 11) 13,990 — Finance lease liability, current (See Note 11) 384 — Deferred revenue 30,071 23,695 Warranty reserve 34,971 36,460 Accrued expenses and other 30,528 41,039 Customer deposits 11,258 10,843 Total other current liabilities $ 174,557 $ 167,735
Schedule of Components of Reserve for Warranty Costs	Components of the reserve for warranty costs during the first nine months of fiscal 2020 and 2019 were as follows (in thousands): Nine Months Ended July 4, June 29, Beginning balance $ 36,460 $ 40,220 Additions related to current period sales 28,669 38,968 Warranty costs incurred in the current period (30,773) (41,204) Accruals resulting from acquisitions — 21 Adjustments to accruals related to foreign exchange and other 615 (453) Ending balance $ 34,971 $ 37,552
Schedule of Other Long-Term Liabilities	Other long-term liabilities consist of the following (in thousands): July 4, September 28, Long-term taxes payable $ 15,554 $ 37,385 Operating lease liability, long-term (See Note 11) 70,091 — Finance lease liability, long-term (See Note 11) 240 — Deferred compensation 38,704 39,715 Defined benefit plan liabilities 46,441 45,862 Deferred tax liabilities 22,312 27,785 Deferred revenue 12,727 8,012 Asset retirement obligations liability 5,418 4,934 Other long-term liabilities 4,351 2,188 Total other long-term liabilities $ 215,838 $ 165,881

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Jul. 04, 2020
Debt Disclosure [Abstract]
Schedule of Short-term Debt	Short-term borrowings and current portion of long-term obligations consist of the following (in thousands): July 4, September 28, Current portion of Euro Term Loan (1) $ 4,764 $ 2,748 1.3% Term loan due 2024 1,410 1,367 1.0% State of Connecticut term loan due 2023 380 378 Capital lease obligations — 370 Line of credit borrowings 10,000 10,000 Total short-term borrowings and current portion of long-term obligations $ 16,554 $ 14,863 (1) Net of debt issuance costs of $2.8 million and $4.6 million at July 4, 2020 and September 28, 2019, respectively.
Schedule of Long-term Debt	Long-term obligations consist of the following (in thousands): July 4, September 28, Euro Term Loan due 2024 (1) $ 391,940 $ 385,208 1.3% Term loan due 2024 4,582 5,466 1.0% State of Connecticut term loan due 2023 742 1,028 Capital lease obligations — 536 Total long-term obligations $ 397,264 $ 392,238 (1) Net of debt issuance costs of $6.4 million and $6.4 million at July 4, 2020 and September 28, 2019, respectively.
Schedule of Maturities of Long-term Debt	Contractual maturities of our debt obligations, excluding line of credit borrowings, as of July 4, 2020 are as follows (in thousands): Amount 2020 (remainder) $ 2,428 2021 9,338 2022 9,338 2023 9,159 2024 382,719 Total $ 412,982

Leases (Tables)

Leases (Tables)	9 Months Ended
	Jul. 04, 2020
Leases [Abstract]
Components of Lease Cost and Supplemental Cash Flow Information	The components of operating lease costs (in thousands), lease term (in years) and discount rate are as follows: Three Months Ended Nine Months Ended July 4, 2020 July 4, 2020 Operating lease cost $ 4,907 $ 14,875 Variable lease cost 348 1,036 Short-term lease cost 123 383 Sublease income (32) (96) Total lease cost $ 5,346 $ 16,198 July 4, 2020 Weighted average remaining lease term 8.1 Weighted average discount rate 4.9 % Supplemental cash flow information related to leases are as follows (in thousands): Nine Months Ended July 4, 2020 Operating cash outflows from operating leases $ 14,672 ROU assets obtained in exchange for new operating lease liabilities 2,746
Operating Lease maturity	As of July 4, 2020, maturities of our operating lease liabilities, which do not include short-term leases and variable lease payments, are as follows (in thousands): Operating Leases 2020 (remainder) $ 3,788 2021 17,582 2022 15,871 2023 12,632 2024 10,128 2025 and thereafter 45,631 Total minimum lease payments 105,632 Amounts representing interest (21,575) Present value of total lease liabilities $ 84,057
Schedule of Maturities Prior to Adoption of ASC 842	As of September 28, 2019, future minimum lease payments as defined under the previous lease accounting guidance of ASC 840 under non-cancellable operating leases were as follows (in thousands): Operating Leases 2020 $ 19,578 2021 14,579 2022 10,405 2023 6,817 2024 4,156 2025 and thereafter 10,755 Total minimum lease payments $ 66,290

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Jul. 04, 2020
Share-based Payment Arrangement [Abstract]
Schedule of Weighted-Average Assumptions Used to Estimate Fair Value of Stock Options Granted and Shares Purchased	The fair values of shares purchased under the Employee Stock Purchase Plan ("ESPP") for the three and nine months ended July 4, 2020 and June 29, 2019, respectively, were estimated using the following weighted-average assumptions: Employee Stock Purchase Plan Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Expected life in years 0.5 0.5 0.5 0.5 Volatility 63.7 % 47.9 % 53.0 % 47.9 % Risk-free interest rate 0.54 % 2.46 % 1.27 % 2.43 % Expected dividend yield — % — % — % — % Weighted average fair value per share $ 43.35 $ 40.42 $ 43.81 $ 40.57
Schedule of Weighted Average Assumptions of Performance Units	The weighted average fair value for the performance units granted for the nine months ended July 4, 2020 and June 29, 2019 was determined using a Monte Carlo simulation model incorporating the following weighted average assumptions: Nine Months Ended Nine Months Ended July 4, June 29, Risk-free interest rate 0.9 % 2.9 % Volatility 50.4 % 43.7 % Weighted average fair value per share $ 162.14 $ 117.43
Schedule of Stock-Based Compensation Expense	The following table shows total stock-based compensation expense and related tax benefits included in the condensed consolidated statements of operations for the three and nine months ended July 4, 2020 and June 29, 2019 (in thousands): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Cost of sales $ 1,237 $ 1,231 $ 3,430 $ 3,640 Research and development 1,469 794 2,924 2,227 Selling, general and administrative 11,680 7,630 24,722 20,668 Income tax benefit (1,552) (1,412) (3,414) (4,106) $ 12,834 $ 8,243 $ 27,662 $ 22,429
Schedule of Restricted Stock Award and Restricted Stock Unit Activity	The following table summarizes the activity of our time-based and performance-based restricted stock units for the first nine months of fiscal 2020 (in thousands, except per share amounts): Time-based Restricted Stock Units Performance-based Restricted Stock Units Number of Weighted Number of Weighted Nonvested stock at September 28, 2019 295 $ 152.47 133 $ 184.26 Granted 277 141.57 82 153.22 Vested (1) (149) 150.71 (81) 163.17 Forfeited (9) 174.40 — — Nonvested stock at July 4, 2020 414 $ 145.35 134 $ 178.08

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Jul. 04, 2020
Earnings Per Share [Abstract]
Schedule of Information Necessary to Calculate Basic and Diluted Earnings (Loss) Per Share	The following table presents information necessary to calculate basic and diluted earnings per share (in thousands, except per share data): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Weighted average shares outstanding—basic 24,159 24,054 24,075 24,185 Dilutive effect of employee stock awards — — — 148 Weighted average shares outstanding—diluted 24,159 24,054 24,075 24,333 Net income (loss) $ (8,708) $ (3,099) $ (421,828) $ 53,201

Other Income (Expense) (Tables)

Other Income (Expense) (Tables)	9 Months Ended
	Jul. 04, 2020
Other Income and Expenses [Abstract]
Schedule of Other Nonoperating Income (Expense)	Other income (expense) is as follows (in thousands): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Foreign exchange loss $ (1,623) $ (518) $ (3,316) $ (5,066) Gain (loss) on deferred compensation investments, net 619 (6) 1,426 (947) Other 499 855 568 2,115 Other—net $ (505) $ 331 $ (1,322) $ (3,898)

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Dec. 28, 2019
Income Tax Disclosure [Abstract]
Schedule of Unrecognized Tax Benefits Roll Forward	The following table summarizes the activity related to our gross unrecognized tax benefits for the nine months ended July 4, 2020 (amounts in thousands): Nine Months Ended July 4, Balance as of the beginning of the year $ 58,111 Increases related to acquisitions — Tax positions related to current year: Additions 1,238 Reductions — Tax positions related to prior year: Additions — Reductions — Settlements — Lapses in statutes of limitations (681) Decrease in unrecognized tax benefits based on tax audit results (19,463) Foreign currency revaluation adjustment 247 Balance as of end of period $ 39,452

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	9 Months Ended
	Jul. 04, 2020
Segment Reporting [Abstract]
Schedule of sales and income (loss) from operations	The following table provides net sales and income (loss) from operations for our operating segments and a reconciliation of our total income (loss) from operations to income (loss) before income taxes (in thousands): Three Months Ended Nine Months Ended July 4, June 29, July 4, June 29, Net sales: OEM Laser Sources $ 184,694 $ 206,285 $ 559,364 $ 680,230 Industrial Lasers & Systems 113,636 132,885 352,884 414,946 Total net sales $ 298,330 $ 339,170 $ 912,248 $ 1,095,176 Income (loss) from operations: OEM Laser Sources $ 42,853 $ 48,310 $ 126,030 $ 190,003 Industrial Lasers & Systems (20,571) (39,569) (512,716) (70,925) Corporate and other (23,456) (15,898) (53,209) (44,557) Total income (loss) from operations (1,174) (7,157) (439,895) 74,521 Total other expense, net (4,282) (4,386) (12,979) (17,789) Income (loss) before income taxes $ (5,456) $ (11,543) $ (452,874) $ 56,732 Three Months Ended Nine Months Ended SALES July 4, June 29, July 4, June 29, United States $ 65,094 $ 82,913 $ 215,236 $ 251,122 Foreign countries: South Korea 63,428 65,717 180,412 235,443 China 52,837 57,519 148,407 152,134 Japan 22,272 24,119 70,990 114,702 Asia-Pacific, other 24,090 23,954 67,889 72,100 Germany 28,650 32,809 90,485 111,646 Europe, other 27,917 38,296 95,130 114,973 Rest of World 14,042 13,843 43,699 43,056 Total foreign countries sales 233,236 256,257 697,012 844,054 Total sales $ 298,330 $ 339,170 $ 912,248 $ 1,095,176

Restructuring Charges (Tables)

Restructuring Charges (Tables)	9 Months Ended
	Jul. 04, 2020
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The table sets forth an analysis of the components of the restructuring charges and payments and other deductions made against the accrual for the quarters of fiscal 2020 and 2019 (in thousands): Severance Related Asset Write-Offs Other Total Balances, September 28, 2019 $ 8,279 $ — $ 215 $ 8,494 Provision 54 599 280 933 Payments and other (658) (599) (275) (1,532) Balances, December 28, 2019 7,675 — 220 7,895 Provision 85 915 79 1,079 Payments and other (3,715) (915) (87) (4,717) Balances, April 4, 2020 4,045 — 212 4,257 Provision (77) 554 41 518 Payments and other (3,136) (554) (31) (3,721) Balances, July 4, 2020 $ 832 $ — $ 222 $ 1,054 Severance Related Asset Write-Offs Other Total Balances, September 29, 2018 $ 836 $ — $ 286 $ 1,122 Provision 212 76 188 476 Payments and other (447) (76) (244) (767) Balances, December 29, 2018 601 — 230 831 Provision 282 247 351 880 Payments and other (201) (247) (516) (964) Balances, March 30, 2019 682 — 65 747 Provision 9,338 11,798 137 21,273 Payments and other 19 (11,798) (34) (11,813) Balances, June 29, 2019 $ 10,039 $ — $ 168 $ 10,207

Basis of Presentation (Details)

Basis of Presentation (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019
Goodwill [Line Items]
Impairment of goodwill	$ 327,203	$ 0
Industrial Lasers & Systems
Goodwill [Line Items]
Impairment of goodwill	$ 327,203

Recent Accounting Standards (De

Recent Accounting Standards (Details) - USD ($) $ in Thousands	Jul. 04, 2020	Sep. 29, 2019	Sep. 28, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset	$ 79,640		$ 0
Present value of total lease liabilities	84,057
Finance lease, right-of-use asset	$ 723		$ 0
Accounting Standards Update 2016-02 | Minimum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use asset		$ 90,400
Finance lease, right-of-use asset		1,000
Present value of total lease liabilities		900
Accounting Standards Update 2016-02 | Maximum
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Present value of total lease liabilities		$ 93,500

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 298,330	$ 339,170	$ 912,248	$ 1,095,176
OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	184,694	206,285	559,364	680,230
Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	113,636	132,885	352,884	414,946
Products | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	109,995	115,992	321,691	412,629
Products | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	91,114	104,784	277,710	329,537
Other products and services revenues | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	74,699	90,293	237,673	267,601
Other products and services revenues | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	22,522	28,101	75,174	85,409
Sales of spare parts
Disaggregation of Revenue [Line Items]
Net sales	15,400	14,100	46,300	40,100
Microelectronics | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	123,635	126,754	343,429	441,597
Microelectronics | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	18,207	16,467	50,726	49,298
Materials processing | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	7,581	11,207	26,373	29,493
Materials processing | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	74,156	90,198	230,043	281,477
OEM components and instrumentation | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	33,588	39,997	120,502	119,027
OEM components and instrumentation | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	19,903	24,300	65,903	78,825
Scientific and government programs | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	19,890	28,327	69,060	90,113
Scientific and government programs | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	$ 1,370	$ 1,920	$ 6,212	$ 5,346

Revenue Recognition Contract ba

Revenue Recognition Contract balances (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Jul. 04, 2020	Jul. 04, 2020	Sep. 28, 2019
Change in Contract with Customer, Liability [Abstract]
Contract with customer, beginning balance		$ 42,550
Additions to customer deposits and deferred revenue		137,747
Amount of customer deposits and deferred revenue recognized in income	$ 48,674	(126,501)
Translation adjustments		260
Contract with customer, ending balance	54,056	54,056
Customer deposits	41,329	41,329	$ 34,538
Customer deposits and deferred revenue, noncurrent	$ 12,727	$ 12,727	$ 8,012

Revenue Recognition Performance

Revenue Recognition Performance Obligations (Details) $ in Thousands	Jul. 04, 2020USD ($)
Revenue from Contract with Customer [Abstract]
Performance Obligations	$ 54,056
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-07-05
Revenue from Contract with Customer [Abstract]
Performance Obligations	$ 27,120
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]: 2020-10-04
Revenue from Contract with Customer [Abstract]
Performance Obligations	$ 26,936
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period	1 year

Business Combinations - Narrati

Business Combinations - Narrative (Details) - USD ($) $ in Millions	Oct. 05, 2018	Jul. 04, 2020
Ondax Inc.
Business Acquisition [Line Items]
Cost investment	$ 12
Ondax Inc. | Minimum
Business Acquisition [Line Items]
Useful life	1 year
Quantum Coating, Inc.
Business Acquisition [Line Items]
Cost investment	$ 7
Quantum Coating, Inc. | Minimum
Business Acquisition [Line Items]
Useful life		1 year
Quantum Coating, Inc. | Maximum
Business Acquisition [Line Items]
Useful life		5 years

Business Combinations - Schedul

Business Combinations - Schedule of Assets Acquired and Liabilities Assumed (Details) - USD ($)	Jul. 04, 2020	Sep. 28, 2019	Oct. 05, 2018
Business Acquisition [Line Items]
Goodwill	$ 98,647,000	$ 427,101,000
Ondax Inc.
Business Acquisition [Line Items]
Cash			$ 103,000
Accounts receivable			534,000
Inventories			1,793,000
Prepaid expenses and other assets			17,000
Deferred tax assets			681,000
Property and equipment			122,000
Liabilities assumed			(499,000)
Goodwill			3,333,000
Total			11,984,000
Ondax Inc. | Developed Technology Rights
Business Acquisition [Line Items]
Intangible assets			5,600,000
Ondax Inc. | Customer relationships
Business Acquisition [Line Items]
Intangible assets			300,000
Quantum Coating, Inc.
Business Acquisition [Line Items]
Property and equipment			2,770,000
Total			7,000,000
Quantum Coating, Inc. | Developed Technology Rights
Business Acquisition [Line Items]
Intangible assets			1,600,000
Quantum Coating, Inc. | Customer relationships
Business Acquisition [Line Items]
Intangible assets			230,000
Quantum Coating, Inc. | Backlog
Business Acquisition [Line Items]
Intangible assets			100,000
Quantum Coating, Inc. | Other Intangible Assets
Business Acquisition [Line Items]
Intangible assets			$ 2,300,000

Fair Values (Details)

Fair Values (Details) - USD ($) $ in Thousands	Jul. 04, 2020	Sep. 28, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of long term obligation, amortized cost	$ 6,600	$ 4,900
Long-term obligations	397,264	392,238
Fair Value, Measurements, Recurring | Prepaid and other assets: | Fair Value, Inputs, Level 1 | Mutual funds — Deferred comp and supplemental plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds - Deferred comp and supplemental plan	19,941	22,419
Fair Value, Measurements, Recurring | Prepaid and other assets: | Fair Value, Inputs, Level 2 | Mutual funds — Deferred comp and supplemental plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds - Deferred comp and supplemental plan	0	0
Fair Value, Measurements, Recurring | Prepaid and other assets: | Estimate of Fair Value Measurement | Mutual funds — Deferred comp and supplemental plan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mutual funds - Deferred comp and supplemental plan	19,941	22,419
Fair Value, Measurements, Recurring | Assets | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets and liabilities, fair value disclosure	134,169	44,274
Fair Value, Measurements, Recurring | Assets | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets and liabilities, fair value disclosure	704	490
Fair Value, Measurements, Recurring | Assets | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets and liabilities, fair value disclosure	134,873	44,764
Fair Value, Measurements, Recurring | Other current liabilities: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets and liabilities, fair value disclosure	134,169	44,274
Fair Value, Measurements, Recurring | Other current liabilities: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets and liabilities, fair value disclosure	(141)	(470)
Fair Value, Measurements, Recurring | Other current liabilities: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets and liabilities, fair value disclosure	134,028	43,804
Fair Value, Measurements, Recurring | Money market fund deposits | Cash equivalents: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	59,052	21,422
Fair Value, Measurements, Recurring | Money market fund deposits | Cash equivalents: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Money market fund deposits | Cash equivalents: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	59,052	21,422
Fair Value, Measurements, Recurring | Money market fund deposits | Prepaid and other assets: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	193	433
Fair Value, Measurements, Recurring | Money market fund deposits | Prepaid and other assets: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	0	0
Fair Value, Measurements, Recurring | Money market fund deposits | Prepaid and other assets: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	193	433
Fair Value, Measurements, Recurring | Certificates of deposit | Cash equivalents: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	13,200	0
Fair Value, Measurements, Recurring | Certificates of deposit | Cash equivalents: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	0	0
Fair Value, Measurements, Recurring | Certificates of deposit | Cash equivalents: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents	13,200	0
Fair Value, Measurements, Recurring | U.S. Treasury and agency obligations | Short-term investments: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	0	0
Fair Value, Measurements, Recurring | U.S. Treasury and agency obligations | Short-term investments: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	115	120
Fair Value, Measurements, Recurring | U.S. Treasury and agency obligations | Short-term investments: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments, fair value disclosure	115	120
Fair Value, Measurements, Recurring | Foreign currency contracts | Prepaid and other assets: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts	0	0
Fair Value, Measurements, Recurring | Foreign currency contracts | Prepaid and other assets: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts	589	370
Fair Value, Measurements, Recurring | Foreign currency contracts | Prepaid and other assets: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts	589	370
Fair Value, Measurements, Recurring | Foreign currency contracts | Other current liabilities: | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts	0	0
Fair Value, Measurements, Recurring | Foreign currency contracts | Other current liabilities: | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts	(845)	(960)
Fair Value, Measurements, Recurring | Foreign currency contracts | Other current liabilities: | Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency contracts	$ (845)	$ (960)

Short-Term Investments (Details

Short-Term Investments (Details) - USD ($)	Jul. 04, 2020	Sep. 28, 2019	Jun. 29, 2019
Schedule of Investments [Line Items]
Cash and cash equivalents, Cost Basis	$ 378,992,000	$ 305,833,000
Cash and cash equivalent, Unrealized Gains	0	0
Cash and cash equivalent, Unrealized Losses	0	0
Cash and cash equivalents	378,992,000	305,833,000	$ 316,458,000
Short-term investments:
Schedule of Investments [Line Items]
Available-for-sale securities, Unrealized Gains	0	0
Available-for-sale securities, Unrealized Losses	0	0
Available-for-sale Securities, Total	41,898,000	120,000
Short-term investments: | U.S. Treasury and agency obligations
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	115,000	120,000
Available-for-sale securities, Unrealized Gains	0	0
Available-for-sale securities, Unrealized Losses	0	0
Available-for-sale securities: Fair Value	115,000	$ 120,000
Time Deposits	$ 41,783,000

Derivative Instruments and He_3

Derivative Instruments and Hedging Activities - Notional and Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019	Sep. 28, 2019
Derivatives, Fair Value [Line Items]
Loss on derivatives	$ 1,100	$ 900	$ 1,200	$ 5,800
Derivatives not designated as hedging instruments | Purchase | Euro
Derivatives, Fair Value [Line Items]
Derivative asset, notional amount	70,682		70,682		$ 53,920
Derivative asset, Fair Value	464		464		(117)
Derivatives not designated as hedging instruments | Sell | Euro
Derivatives, Fair Value [Line Items]
Derivative liability, notional amount	(86,375)		(86,375)		(86,984)
Derivative liability, Fair Value	$ (720)		$ (720)		$ (473)

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Apr. 04, 2020	Jul. 04, 2020	Jun. 29, 2019
Goodwill [Line Items]
Impairment charges		$ (327,203)	$ 0
Industrial Lasers & Systems
Goodwill [Line Items]
Impairment charges		$ (327,203)
Intangible Assets | Industrial Lasers & Systems
Goodwill [Line Items]
Non-cash pre-tax charges	$ 33,900
Property, Plant and Equipment | Industrial Lasers & Systems
Goodwill [Line Items]
Non-cash pre-tax charges	85,600
Right-Of-Use Assets | Industrial Lasers & Systems
Goodwill [Line Items]
Non-cash pre-tax charges	$ 1,800

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Carrying Amount of Goodwill (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019
Goodwill [Roll Forward]
Goodwill, beginning of period	$ 427,101
Impairment charges	(327,203)	$ 0
Translation adjustments	(1,251)
Goodwill, end of period	98,647
OEM Laser Sources
Goodwill [Roll Forward]
Goodwill, beginning of period	96,820
Impairment charges	0
Translation adjustments	1,827
Goodwill, end of period	98,647
Industrial Lasers & Systems
Goodwill [Roll Forward]
Goodwill, beginning of period	330,281
Impairment charges	(327,203)
Translation adjustments	(3,078)
Goodwill, end of period	$ 0

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Sep. 28, 2019
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 69,490		$ 243,348
Accumulated Amortization	(45,485)		(158,535)
Net including IPRD	24,005		84,813
Amortization expense for intangible assets	(27,166)	$ (47,725)
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2020 (remainder)	2,918
2021	9,404
2022	3,186
2023	2,639
2024	1,854
2025	1,852
Thereafter	2,152
Net excluding IPRD	24,005
Existing technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	43,114		193,704
Accumulated Amortization	(32,181)		(131,429)
Net including IPRD	10,933		62,275
Impairment charges	27,700
Customer relationships
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	24,076		42,083
Accumulated Amortization	(12,503)		(21,512)
Net including IPRD	11,573		20,571
Impairment charges	6,200
Trade name
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	0		5,261
Accumulated Amortization	0		(5,138)
Net including IPRD	0		123
Production know-how
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	2,300		2,300
Accumulated Amortization	(801)		(456)
Net including IPRD	1,499		$ 1,844
Foreign exchange
Finite-Lived Intangible Assets, Net [Abstract]
Amortization expense for intangible assets	$ 1,800	$ (2,100)

Balance Sheet Details (Details)

Balance Sheet Details (Details) $ in Thousands, € in Millions	3 Months Ended	9 Months Ended
	Jul. 04, 2020USD ($)	Jul. 04, 2020USD ($)	Jun. 29, 2019USD ($)	Sep. 28, 2019USD ($)	Mar. 30, 2019USD ($)	Mar. 30, 2019EUR (€)
Inventory, Net [Abstract]
Purchased parts and assemblies	$ 127,885	$ 127,885		$ 134,298
Work-in-process	178,801	178,801		174,550
Finished goods	142,286	142,286		133,682
Total inventories	448,972	448,972		442,530
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid and refundable income taxes	56,467	56,467		44,096
Other taxes receivable	9,410	9,410		11,208
Prepaid expenses and other assets	24,360	24,360		22,689
Total prepaid expenses and other assets	90,237	90,237		77,993
Other Assets, Noncurrent Disclosure [Abstract]
Assets related to deferred compensation arrangements	35,042	35,042		35,842
Deferred tax assets	103,507	103,507		87,011
Right of use assets, net - operating leases (See Note 11)	79,640	79,640		0
Right of use assets, net - finance leases (See Note 11)	723	723		0
Other assets	14,030	14,030		18,111
Total other assets	232,942	232,942		140,964
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-cash impairment charge on investment	2,500	2,472	$ 0
Other Liabilities, Current [Abstract]
Accrued payroll and benefits	53,355	53,355		55,698
Operating lease liability, current (See Note 11)	13,990	13,990		0
Finance lease liability, current (See Note 11)	384	384		0
Deferred revenue	30,071	30,071		23,695
Warranty reserve	34,971	34,971		36,460
Accrued expenses and other	30,528	30,528		41,039
Customer deposits	11,258	11,258		10,843
Total other current liabilities	174,557	174,557		167,735
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Beginning balance		36,460	40,220
Additions related to current period sales		28,669	38,968
Warranty costs incurred in the current period		(30,773)	(41,204)
Accruals resulting from acquisitions		0	21
Adjustments to accruals related to foreign exchange and other		615	(453)
Ending balance	34,971	34,971	$ 37,552
Other Liabilities, Noncurrent [Abstract]
Long-term taxes payable	15,554	15,554		37,385
Operating lease liability, long-term (See Note 11)	70,091	70,091		0
Finance lease liability, long-term (See Note 11)	240	240		0
Deferred compensation	38,704	38,704		39,715
Defined benefit plan liabilities	46,441	46,441		45,862
Deferred tax liabilities	22,312	22,312		27,785
Deferred revenue	12,727	12,727		8,012
Asset retirement obligations liability	5,418	5,418		4,934
Other long-term liabilities	4,351	4,351		2,188
Total other long-term liabilities	$ 215,838	$ 215,838		$ 165,881
Euro
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity method investments | €						€ 3
United States of America, Dollars
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity method investments					$ 3,400

Borrowings (Details)

Borrowings (Details) € in Millions	May 08, 2018	Apr. 01, 2017USD ($)	Sep. 30, 2017USD ($)	Jul. 04, 2020EUR (€)	Jul. 04, 2020USD ($)	Nov. 07, 2016EUR (€)	Nov. 07, 2016USD ($)
Debt [Line Items]
Additional sources of cash available					$ 16,400,000
Debt instrument, unused borrowing capacity, amount					13,500,000
Rofin-Sinar
Debt [Line Items]
Lines of credit, maximum borrowing capacity							$ 30,000,000
Swing line, maximum borrowing capacity							$ 10,000,000
Credit agreement november 7 2016
Debt [Line Items]
Senior secured net leverage ratio to maintain compliance on the loan each quarter end						3.50	3.50
Euro
Debt [Line Items]
Domestic line of credit drawn | €						€ 10
Euro term loan
Debt [Line Items]
Debt Issuance costs for revolving credit facility		$ 28,500,000
Amortization period of the debt issuance cost			7 years
Short-term Debt [Line Items]
Debt Issuance costs for revolving credit facility		28,500,000
Debt Issuance Costs, Gross		$ 500,000
Euro term loan | Minimum | Eurodollar
Debt [Line Items]
Debt instrument, interest rate, stepdown	1.25%
Euro term loan | Euro
Debt [Line Items]
Borrowed under forward contract purchased for the term loan | €						€ 670
Forward contract purchased for the term loan | €				€ 359.9
Additional euro currency rate						0.010	0.010
Quarter principal payment requirement for euro term loan						0.0025	0.0025
Euro term loan | Euro | Minimum
Debt [Line Items]
Applicable margin for eurocurrency rate loan						0.0400	0.0400
Revolving line of credit
Debt [Line Items]
Revolving facility to finance acquisition of rofin							$ 100,000,000
Revolving facility to finance acquisition of Rofin, outstanding balance					10,000,000
Additional base rate						0.0050	0.0050
Debt Issuance costs for revolving credit facility			$ 2,300,000
debt issuance cost amortization period			5 years
Short-term Debt [Line Items]
Debt Issuance costs for revolving credit facility			$ 2,300,000
Revolving line of credit | Minimum
Debt [Line Items]
Base rate range after 1st year						0.0225	0.0225
Applicable margin for base rate revolving loan						0.0300	0.0300
Commitment fee accrues range on unused portion of revolving loan						0.00375	0.00375
Revolving line of credit | Maximum
Debt [Line Items]
Commitment fee accrues range on unused portion of revolving loan						0.005	0.005
Line of Credit, Foreign | Europe, other
Debt [Line Items]
Amounts drawn upon line of credit					$ 2,900,000

Borrowings - Borrowings obligat

Borrowings - Borrowings obligation table (Details) $ in Thousands	Apr. 04, 2020USD ($)	Sep. 28, 2019USD ($)	Jul. 04, 2020USD ($)	Apr. 01, 2017USD ($)
Short-term Debt [Line Items]
Total short-term borrowings and current portion of long-term obligations		$ 14,863	$ 16,554
Euro term loan
Short-term Debt [Line Items]
Debt issuance cost for long term portion of the euro term loan	$ 6,400	6,400
Debt Issuance Costs, Gross				$ 500
Revolving line of credit
Short-term Debt [Line Items]
Interest rate of term loan			0.013
Interest rate of state of Connecticut			0.010
Euro term loan
Short-term Debt [Line Items]
Debt issuance cost for short term euro term loan	$ 2,800	4,600
Short-term Debt
Short-term Debt [Line Items]
Euro Term Loan due 2024		2,748	$ 4,764
1.3% Term loan due 2024		1,367	1,410
1.0% State of Connecticut term loan due 2023		378	380
Capital lease obligations		370	0
Line of credit borrowings		10,000	10,000
Total short-term borrowings and current portion of long-term obligations		14,863	16,554
Long-term Debt
Short-term Debt [Line Items]
Euro Term Loan due 2024		385,208	391,940
1.3% Term loan due 2024		5,466	4,582
1.0% State of Connecticut term loan due 2023		1,028	742
Capital lease obligations		536	0
Long-term Debt		$ 392,238	$ 397,264

Borrowings - Debt Maturity Tabl

Borrowings - Debt Maturity Table (Details) $ in Thousands	Jul. 04, 2020USD ($)
Debt Disclosure [Abstract]
2020 (remainder)	$ 2,428
2021	9,338
2022	9,338
2023	9,159
2024	382,719
Total contractual obligation due amount	$ 412,982

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 04, 2020	Jul. 04, 2020
Minimum
Lessee, Lease, Description [Line Items]
Finance lease arrangements		3 years
Maximum
Lessee, Lease, Description [Line Items]
Finance lease arrangements		6 years
Right-Of-Use Assets | Industrial Lasers & Systems
Lessee, Lease, Description [Line Items]
Non-cash pre-tax charges	$ 1.8

Leases - Components of Lease Co

Leases - Components of Lease Cost (Details) $ in Thousands	3 Months Ended	9 Months Ended
	Jul. 04, 2020USD ($)	Jul. 04, 2020USD ($)
Leases [Abstract]
Operating lease cost	$ 4,907	$ 14,875
Variable lease cost	348	1,036
Short-term lease cost	123	383
Sublease income	(32)	(96)
Total lease cost	$ 5,346	$ 16,198
Weighted average remaining lease term	8 years 1 month 6 days	8 years 1 month 6 days
Weighted average discount rate	4.90%	4.90%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) $ in Thousands	9 Months Ended
	Jul. 04, 2020USD ($)
Leases [Abstract]
Operating cash outflows from operating leases	$ 14,672
ROU assets obtained in exchange for new operating lease liabilities	$ 2,746

Leases - Schedule of Maturities

Leases - Schedule of Maturities After Adoption of ASC 842 (Details) $ in Thousands	Jul. 04, 2020USD ($)
Operating Leases
2020 (remainder)	$ 3,788
2021	17,582
2022	15,871
2023	12,632
2024	10,128
2025 and thereafter	45,631
Total minimum lease payments	105,632
Amounts representing interest	(21,575)
Present value of total lease liabilities	$ 84,057

Leases - Schedule of Maturiti_2

Leases - Schedule of Maturities before Adoption of ASC 842 (Details) $ in Thousands	Sep. 28, 2019USD ($)
Operating Leases
2020	$ 19,578
2021	14,579
2022	10,405
2023	6,817
2024	4,156
2025 and thereafter	10,755
Total minimum lease payments	$ 66,290

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Stock Compensation (Details) - $ / shares	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Common shares that restricted stock units with each unit representing			1
Requisite service period			3 years
Employee stock
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Expected life in years	6 months	6 months	6 months	6 months
Volatility	63.70%	47.90%	53.00%	47.90%
Risk-free interest rate	0.54%	2.46%	1.27%	2.43%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average fair value per share	$ 43.35	$ 40.42	$ 43.81	$ 40.57
Performance restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Volatility			50.40%	43.70%
Risk-free interest rate			0.90%	2.90%
Weighted average fair value per share			$ 162.14	$ 117.43

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	$ 12,834	$ 8,243	$ 27,662	$ 22,429
Capitalized share-based compensation costs	2,100	1,200	4,300	3,600
Amortization of capitalized share-based compensation expenses	1,200	1,200	3,400	3,600
Total compensation cost, unvested stock-based awards granted but not yet recognized	49,500		$ 49,500
Total compensation cost, weighted-average period of amortization (in years)			1 year 4 months 24 days
Share-based Payment Arrangement, Accelerated Cost	3,500
Period End
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Capitalized share-based compensation remaining	2,400	1,500	$ 2,400	1,500
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	1,237	1,231	3,430	3,640
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	1,469	794	2,924	2,227
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	11,680	7,630	24,722	20,668
Income tax benefit
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Income tax benefit	$ (1,552)	$ (1,412)	$ (3,414)	$ (4,106)

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Options and Awards Activity (Details) - $ / shares shares in Thousands	3 Months Ended	9 Months Ended
	Jul. 04, 2020	Jul. 04, 2020
Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested stock, beginning of period (in shares)		295
Granted (in shares)		277
Vested (in shares)		(149)
Forfeited (in shares)		(9)
Nonvested stock, end of period (in shares)	414	414
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Nonvested stock, beginning of period (in dollars per share)		$ 152.47
Granted (in dollars per share)		141.57
Vested (in dollars per share)		150.71
Forfeited (in dollars per share)		174.40
Nonvested stock, end of period (in dollars per share)	$ 145.35	$ 145.35
Performance restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested stock, beginning of period (in shares)		133
Granted (in shares)		82
Vested (in shares)		(81)
Forfeited (in shares)		0
Nonvested stock, end of period (in shares)	134	134
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Nonvested stock, beginning of period (in dollars per share)		$ 184.26
Granted (in dollars per share)		153.22
Vested (in dollars per share)		163.17
Forfeited (in dollars per share)		0
Nonvested stock, end of period (in dollars per share)	$ 178.08	$ 178.08
Restricted Stock Units and Awards [Abstract]
Targeted goal of performance based awards and units	100.00%
Performance restricted stock units | Minimum
Restricted Stock Units and Awards [Abstract]
Percentage of performance-based awards earned by recipient	0.00%
Performance restricted stock units | Maximum
Restricted Stock Units and Awards [Abstract]
Percentage of performance-based awards earned by recipient	200.00%

Commitments and Contingencies E

Commitments and Contingencies Export compliance matter (Details) € in Millions	9 Months Ended
	Jul. 04, 2020EUR (€)
Commitments and Contingencies Disclosure [Abstract]
Export compliance related transactions	€ 1.5

Stock Repurchases (Details)

Stock Repurchases (Details) - USD ($)	3 Months Ended
	Dec. 28, 2019	Feb. 05, 2020	Oct. 28, 2018
Class of Stock [Line Items]
Stock repurchase program, authorized amount		$ 100,000,000	$ 250,000,000
Oct 2018 repurchase program
Class of Stock [Line Items]
Repurchase limit per quarter			$ 75,000,000
Feb 2018 repurchase program
Class of Stock [Line Items]
Stock repurchased and retired during period (in shares)	603,828
Stock repurchase, price paid per share (in dollars per share)	$ 128.20
Total cost of stock repurchased, net	$ 77,400,000

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jul. 04, 2020	Apr. 04, 2020	Dec. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Jul. 04, 2020	Jun. 29, 2019
Earnings Per Share, Basic and Diluted [Abstract]
Weighted average shares outstanding—basic (in shares)	24,159,000			24,054,000			24,075,000	24,185,000
Dilutive effect of employee stock awards (in shares)	0			0			0	148,000
Weighted average shares outstanding—diluted (in shares)	24,159,000			24,054,000			24,075,000	24,333,000
Net income (loss)	$ (8,708)	$ (418,913)	$ 5,793	$ (3,099)	$ 20,750	$ 35,550	$ (421,828)	$ 53,201
Earnings Per Share, Diluted, Other Disclosures [Abstract]
Dilutive securities excluded from calculation of dilutive shares				0				97,420

Other Income (Expense) (Details

Other Income (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Component of Other Income (Expense), Nonoperating [Line Items]
Other—net	$ (505)	$ 331	$ (1,322)	$ (3,898)
Foreign exchange loss
Component of Other Income (Expense), Nonoperating [Line Items]
Foreign exchange loss	(1,623)	(518)	(3,316)	(5,066)
Gain (loss) on deferred compensation investments, net
Component of Other Income (Expense), Nonoperating [Line Items]
Gain (loss) on deferred compensation investments, net	619	(6)	1,426	(947)
Other
Component of Other Income (Expense), Nonoperating [Line Items]
Other	$ 499	$ 855	$ 568	$ 2,115

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Millions	Dec. 22, 2017	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Income Tax Disclosure [Abstract]
U.S. federal statutory rate	21.00%
Effective income tax rate (percent)		(59.60%)	73.20%	6.90%	6.20%
Gross interest and penalties accrued		$ 2.7		$ 2.7

Income Taxes - Gross Unrecogniz

Income Taxes - Gross Unrecognized Tax Benefits (Details) $ in Thousands	9 Months Ended
	Jul. 04, 2020USD ($)
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance as of the beginning of the year	$ 58,111
Increases related to acquisitions	0
Tax positions related to current year:
Additions	1,238
Reductions	0
Unrecognized Tax Benefits, Prior Period Tax Positions [Abstract]
Additions	0
Reductions	0
Lapses in statutes of limitations	(681)
Decrease in unrecognized tax benefits based on tax audit results	(19,463)
Foreign currency revaluation adjustment	247
Balance as of end of period	$ 39,452

Defined Benefit Plans (Details)

Defined Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Postemployment Benefits [Abstract]
Net periodic pension (benefit) cost	$ 0.6	$ (0.4)	$ 1.4	$ 0.2

Segment and Geographic Inform_3

Segment and Geographic Information - Sales and Income (Loss) from Operations (Details) $ in Thousands	Apr. 04, 2020segments	Jul. 04, 2020USD ($)	Jun. 29, 2019USD ($)	Jul. 04, 2020USD ($)	Jun. 29, 2019USD ($)
Segment Reporting [Abstract]
Number of reporting segments | segments	2
Segment Reporting Information [Line Items]
Net sales		$ 298,330	$ 339,170	$ 912,248	$ 1,095,176
Total income (loss) from operations		(1,174)	(7,157)	(439,895)	74,521
Total other expense, net		(4,282)	(4,386)	(12,979)	(17,789)
Income (loss) before income taxes		(5,456)	(11,543)	(452,874)	56,732
OEM Laser Sources
Segment Reporting Information [Line Items]
Net sales		184,694	206,285	559,364	680,230
Income (loss) from operations:		42,853	48,310	126,030	190,003
Industrial Lasers & Systems
Segment Reporting Information [Line Items]
Net sales		113,636	132,885	352,884	414,946
Income (loss) from operations:		(20,571)	(39,569)	(512,716)	(70,925)
Corporate and other
Segment Reporting Information [Line Items]
Income (loss) from operations:		$ (23,456)	$ (15,898)	$ (53,209)	$ (44,557)

Segment and Geographic Inform_4

Segment and Geographic Information - Schedule of sales by geographic regions (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Jul. 04, 2020	Jun. 29, 2019
Geographic information [Line Items]
Net sales	$ 298,330	$ 339,170	$ 912,248	$ 1,095,176
United States
Geographic information [Line Items]
Net sales	65,094	82,913	215,236	251,122
Total foreign countries sales
Geographic information [Line Items]
Net sales	233,236	256,257	697,012	844,054
South Korea
Geographic information [Line Items]
Net sales	63,428	65,717	180,412	235,443
China
Geographic information [Line Items]
Net sales	52,837	57,519	148,407	152,134
Japan
Geographic information [Line Items]
Net sales	22,272	24,119	70,990	114,702
Asia-Pacific, other
Geographic information [Line Items]
Net sales	24,090	23,954	67,889	72,100
Germany
Geographic information [Line Items]
Net sales	28,650	32,809	90,485	111,646
Europe, other
Geographic information [Line Items]
Net sales	27,917	38,296	95,130	114,973
Rest of World
Geographic information [Line Items]
Net sales	$ 14,042	$ 13,843	$ 43,699	$ 43,056

Segment and Geographic Inform_5

Segment and Geographic Information - Major Customers (Details) - Customer Concentration Risk	3 Months Ended		6 Months Ended	9 Months Ended
	Jul. 04, 2020	Jun. 29, 2019	Mar. 30, 2019	Jul. 04, 2020	Jun. 29, 2019
Sales | Customer 1
Concentration Risk [Line Items]
Concentration risk, percentage	17.10%	15.60%		16.70%	15.90%
Accounts receivable | Customer 3
Concentration Risk [Line Items]
Concentration risk, percentage	22.30%		28.60%

Restructuring Charges (Details)

Restructuring Charges (Details) - USD ($)	3 Months Ended						9 Months Ended
	Jul. 04, 2020	Apr. 04, 2020	Dec. 28, 2019	Jun. 29, 2019	Mar. 30, 2019	Dec. 29, 2018	Jul. 04, 2020	Jun. 29, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring cost relating to HPFL products at Germany facility			$ 20,900,000
Restructuring Reserve [Roll Forward]
Starting balance	$ 4,257,000	$ 7,895,000	8,494,000	$ 747,000	$ 831,000	$ 1,122,000	$ 8,494,000	$ 1,122,000
Provision	518,000	1,079,000	933,000	21,273,000	880,000	476,000
Payments and other	(3,721,000)	(4,717,000)	(1,532,000)	(11,813,000)	(964,000)	(767,000)
Ending balance	1,054,000	4,257,000	7,895,000	10,207,000	747,000	831,000	1,054,000	10,207,000
Restructuring cost incurred	100,000
Restructuring charges relating to accelerated depreciation and consulting	100,000	500,000	600,000
Santa Clara facility combine project related restructuring charge	400,000	600,000	200,000
Industrial Lasers & Systems
Restructuring Reserve [Roll Forward]
Restructuring cost incurred	100,000						1,300,000
OEM Laser Sources
Restructuring Reserve [Roll Forward]
Restructuring cost incurred	400,000						1,200,000	0
Severance Related
Restructuring Reserve [Roll Forward]
Starting balance	4,045,000	7,675,000	8,279,000	682,000	601,000	836,000	8,279,000	836,000
Provision	(77,000)	85,000	54,000	9,338,000	282,000	212,000
Payments and other	(3,136,000)	(3,715,000)	(658,000)	19,000	(201,000)	(447,000)
Ending balance	832,000	4,045,000	7,675,000	10,039,000	682,000	601,000	832,000	10,039,000
Severance Related | Other current liabilities
Restructuring Reserve [Roll Forward]
Ending balance	1,100,000						1,100,000
Asset Write-Offs
Restructuring Reserve [Roll Forward]
Starting balance	0	0	0	0	0	0	0	0
Provision	554,000	915,000	599,000	11,798,000	247,000	76,000
Payments and other	(554,000)	(915,000)	(599,000)	(11,798,000)	(247,000)	(76,000)
Ending balance	0	0	0	0	0	0	0	0
Other
Restructuring Reserve [Roll Forward]
Starting balance	212,000	220,000	215,000	65,000	230,000	286,000	215,000	286,000
Provision	41,000	79,000	280,000	137,000	351,000	188,000
Payments and other	(31,000)	(87,000)	(275,000)	(34,000)	(516,000)	(244,000)
Ending balance	$ 222,000	$ 212,000	$ 220,000	$ 168,000	$ 65,000	$ 230,000	$ 222,000	$ 168,000