Coherent 10-Q 11 Aug 21 2021 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Jul. 03, 2021	Aug. 06, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jul. 3, 2021
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		24,535,214
Entity Central Index Key	0000021510
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Current Fiscal Year End Date	--10-02
Amendment flag	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Income Statement [Abstract]
Net sales	$ 395,759	$ 298,330	$ 1,095,794	$ 912,248
Cost of sales	239,776	203,053	678,790	613,607
Gross profit	155,983	95,277	417,004	298,641
Operating expenses:
Research and development	31,982	28,283	92,210	86,757
Selling, general and administrative	78,219	67,525	225,109	197,383
Merger and acquisition costs	2,578	0	234,574	0
Goodwill and other impairment charges	0	0	0	451,025
Amortization of intangible assets	1,100	643	2,293	3,371
Total operating expenses	113,879	96,451	554,186	738,536
Income (loss) from operations	42,104	(1,174)	(137,182)	(439,895)
Other income (expense):
Interest income	90	269	361	906
Interest expense	(4,552)	(4,046)	(13,541)	(12,563)
Other—net	1,185	(505)	5,088	(1,322)
Total other expense, net	(3,277)	(4,282)	(8,092)	(12,979)
Income (loss) before income taxes	38,827	(5,456)	(145,274)	(452,874)
Provision for (benefit from) income taxes	8,565	3,252	(17,465)	(31,046)
Net income (loss)	$ 30,262	$ (8,708)	$ (127,809)	$ (421,828)
Net income (loss) per share:
Basic (in USD per share)	$ 1.24	$ (0.36)	$ (5.25)	$ (17.52)
Diluted (in USD per share)	$ 1.22	$ (0.36)	$ (5.25)	$ (17.52)
Shares used in computation:
Basic (shares)	24,435	24,159	24,362	24,075
Diluted (shares)	24,842	24,159	24,362	24,075

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Statement of Comprehensive Income [Abstract]
Net income (loss)		$ 30,262	$ (8,708)	$ (127,809)	$ (421,828)
Other comprehensive income (loss):
Translation adjustment, net of taxes	[1],[2]	(1,853)	8,183	6,823	(1,916)
Changes in unrealized gains on available-for-sale securities, net of taxes	[1],[3]	(3)	0	(1)	0
Defined benefit pension plans, net of taxes	[1],[4]	192	(920)	97	690
Other comprehensive income (loss), net of tax	[1]	(1,664)	7,263	6,919	(1,226)
Comprehensive income (loss)		$ 28,598	$ (1,445)	$ (120,890)	$ (423,054)
[1]	Reclassification adjustments were not significant during the three and nine months ended July 3, 2021 and July 4, 2020.
[2]	Tax expenses of $404 and $1,260 were provided on translation adjustments during the three and nine months ended July 3, 2021, respectively. Tax expenses of $2,268 and $1,459 were provided on translation adjustments during the three and nine months ended July 4, 2020, respectively.
[3]	Tax benefits of $1 and $0 were provided on changes in unrealized gains on available-for-sale securities during the three and nine months ended July 3, 2021, respectively. Tax expenses (benefits) were not provided on changes in unrealized gains on available-for-sale securities during the three and nine months ended July 4, 2020.
[4]	Tax expenses of $144 and $176 were provided on changes in defined benefit pension plans for the three and nine months ended July 3, 2021, respectively. 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.

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	$ 404	$ 2,268	$ 1,260	$ 1,459
OCI, Debt Securities, Available-for-Sale, Gain (Loss), after Adjustment, Tax	1		0
Defined benefit plans, tax benefits	$ 144	$ (445)	$ 176	$ 230

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jul. 03, 2021	Oct. 03, 2020
Current assets:
Cash and cash equivalents	$ 394,098	$ 440,258
Restricted cash	1,559	765
Short-term investments	15,129	35,346
Accounts receivable	256,197	220,289
Inventories	400,547	426,756
Prepaid expenses and other assets	87,744	88,250
Total current assets	1,155,274	1,211,664
Property and equipment, net	295,481	245,678
Goodwill	106,654	101,317
Intangible assets, net	17,496	21,765
Non-current restricted cash	14,587	4,497
Other assets	272,695	242,575
Total assets	1,862,187	1,827,496
Current liabilities:
Short-term borrowings and current-portion of long-term obligations	17,730	16,817
Accounts payable	108,831	60,225
Income taxes payable	12,784	6,861
Other current liabilities	231,922	184,155
Total current liabilities	371,267	268,058
Long-term obligations	437,269	411,140
Other long-term liabilities	214,195	221,074
Commitments and contingencies (Note 13)
Stockholders' equity:
Common stock, value	244	241
Additional paid-in capital	113,394	80,275
Accumulated other comprehensive loss	(18,748)	(25,667)
Retained earnings	744,566	872,375
Total stockholders' equity	839,456	927,224
Total liabilities and stockholders' equity	$ 1,862,187	$ 1,827,496

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jul. 03, 2021	Oct. 03, 2020
Statement of Financial Position [Abstract]
Accounts Receivable, Allowance for Credit Loss	$ 6,715	$ 7,630
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	24,535,000	24,257,000

Condensed Consolidated Statem_4

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. 28, 2019		$ 1,284,736		$ 238	$ 34,320	$ (36,336)	$ 1,286,514
Beginning balance (in shares) at Sep. 28, 2019				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 (loss)		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
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(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
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 (loss)		(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 (loss)		(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
Beginning balance at Oct. 03, 2020		$ 927,224		$ 241	80,275	(25,667)	872,375
Beginning balance (in shares) at Oct. 03, 2020		24,257,000		24,257,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		$ (3,007)		$ 2	(3,009)
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				190,000
Stock-based compensation		11,798			11,798
Net income (loss)		144					144
Other comprehensive income (loss), net of tax		15,719				15,719
Ending balance at Jan. 02, 2021		951,878		$ 243	89,064	(9,948)	872,519
Ending balance (in shares) at Jan. 02, 2021				24,447,000
Beginning balance at Oct. 03, 2020		$ 927,224		$ 241	80,275	(25,667)	872,375
Beginning balance (in shares) at Oct. 03, 2020		24,257,000		24,257,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		$ (127,809)
Other comprehensive income (loss), net of tax	[1]	6,919
Ending balance at Jul. 03, 2021		$ 839,456		$ 244	113,394	(18,748)	744,566
Ending balance (in shares) at Jul. 03, 2021		24,535,000		24,535,000
Beginning balance at Jan. 02, 2021		$ 951,878		$ 243	89,064	(9,948)	872,519
Beginning balance (in shares) at Jan. 02, 2021				24,447,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		(348)			(348)
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				17,000
Stock-based compensation		8,774			8,774
Net income (loss)		(158,215)					(158,215)
Other comprehensive income (loss), net of tax		(7,136)				(7,136)
Ending balance at Apr. 03, 2021		794,953		$ 243	97,490	(17,084)	714,304
Ending balance (in shares) at Apr. 03, 2021				24,464,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued under stock plans, net of shares withheld for employee taxes		5,757		$ 1	5,756
Common stock issued under stock plans, net of shares withheld for employee taxes (in shares)				71,000
Stock-based compensation		10,148			10,148
Net income (loss)		30,262					30,262
Other comprehensive income (loss), net of tax		(1,664)	[1]			(1,664)
Ending balance at Jul. 03, 2021		$ 839,456		$ 244	$ 113,394	$ (18,748)	$ 744,566
Ending balance (in shares) at Jul. 03, 2021		24,535,000		24,535,000
[1]	Reclassification adjustments were not significant during the three and nine months ended July 3, 2021 and July 4, 2020.

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020
Cash flows from operating activities:
Net income (loss)	$ (127,809)	$ (421,828)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	32,814	36,257
Amortization of intangible assets	8,174	27,166
Impairment of goodwill	0	327,203
Impairment of long-lived assets	0	121,350
Impairment of investment	0	2,472
Deferred income taxes	(45,326)	(21,797)
Amortization of debt issuance cost	2,611	2,451
Stock-based compensation	31,425	31,076
Non-cash restructuring charges	4,385	2,068
Amortization of right of use assets	13,446	12,146
Other non-cash expense	1,489	1,647
Changes in assets and liabilities, net of effect of acquisitions:
Accounts receivable	(33,189)	71,723
Inventories	28,015	(164)
Prepaid expenses and other assets	(11,592)	(626)
Other long-term assets	4,482	1,391
Accounts payable	44,446	14,716
Income taxes payable/receivable	21,815	(33,642)
Operating lease liabilities	(12,823)	(12,342)
Other current liabilities	46,426	(5,194)
Other long-term liabilities	(5,704)	3,991
Net cash provided by operating activities	3,085	160,064
Cash flows from investing activities:
Purchases of property and equipment	(60,496)	(48,436)
Proceeds from dispositions of property and equipment	2,770	668
Purchases of available-for-sale securities	0	(42,018)
Proceeds from sales and maturities of available-for-sale securities	20,281	240
Acquisition of businesses, net of cash acquired	(28,810)	0
Net cash used in investing activities	(66,255)	(89,546)
Cash flows from financing activities:
Short-term borrowings	0	12,695
Long-term borrowings	28,885	0
Repayments of short-term borrowings	(1,411)	(14,010)
Repayments of long-term borrowings	(6,525)	(5,865)
Issuance of common stock under employee stock option and purchase plans	12,483	13,361
Net settlement of restricted common stock	(10,081)	(13,519)
Net cash provided by (used in) financing activities	23,351	(7,338)
Effect of exchange rate changes on cash, cash equivalents and restricted cash	4,543	2,373
Net increase (decrease) in cash, cash equivalents and restricted cash	(35,276)	65,553
Cash, cash equivalents and restricted cash, beginning of period	445,520	318,661
Cash, cash equivalents and restricted cash, end of period	410,244	384,214
Non-cash investing and financing activities:
Unpaid property and equipment purchases	$ 5,706	$ 5,826

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows - Reconciliation - USD ($) $ in Thousands	Jul. 03, 2021	Oct. 03, 2020	Jul. 04, 2020	Sep. 28, 2019
Statement of Cash Flows [Abstract]
Cash and cash equivalents	$ 394,098	$ 440,258	$ 378,992
Restricted cash, current	1,559	765	736
Restricted cash, non-current	14,587	4,497	4,486
Total cash, cash equivalents, and restricted cash shown in the condensed consolidated statement of cash flows	$ 410,244	$ 445,520	$ 384,214	$ 318,661

Basis of Presentation

Basis of Presentation	9 Months Ended
	Jul. 03, 2021
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 October 3, 2020. 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 both fiscal 2021 and fiscal 2020. Fiscal 2021 includes 52 weeks and fiscal 2020 includes 53 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 some 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, it could 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.

Recent Accounting Standards

Recent Accounting Standards	9 Months Ended
	Jul. 03, 2021
Accounting Policies [Abstract]
Recent Accounting Standards	RECENT ACCOUNTING STANDARDS Adoption of New Accounting Pronouncement In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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. We adopted ASU 2016-13 in the first quarter of fiscal 2021 with no material impact to our condensed consolidated financial statements. With the adoption of Topic 326, we are now assessing whether unrealized losses have resulted from a credit loss or other factors. We believe none of our unrealized losses on available-for-sale investments were other-than temporary or were attributable to credit losses as of July 3, 2021 and October 3, 2020 . We review our available-for-sale investments on a quarterly basis to identify a potential other-than-temporary impairment. We also do not have an intent to sell our investments and would not be required to sell them before they recover. The adoption of Topic 326 did not significantly change our approach to the valuation of trade receivables. We determine whether there is an expected loss on our accounts receivable by reviewing all available data, including our customers' latest available financial statements, their credit standing and our historical collection experience, as well as current and future market and economic conditions. As of July 3, 2021 and October 3, 2020, the allowance for credit losses on our trade receivables was $4.9 million and $5.4 million, respectively. Recently Issued Accounting Pronouncements In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform ("Topic 848"). Topic 848 provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by the discontinuation of the London Interbank Offered Rate ("LIBOR") or by another reference rate expected to be discontinued. The guidance was effective beginning March 12, 2020 and can be applied prospectively through December 31, 2022. In January 2021, the FASB issued ASU 2021-01, "Reference Rate Reform - Scope," which clarified the scope and application of the original guidance. We will adopt these standards when LIBOR is discontinued and do not expect them to have a material impact on our consolidated financial statements or related disclosures.

Revenue Recognition

Revenue Recognition	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 145,219 $ 132,461 $ 109,995 $ 91,114 Other product and service revenues (2) 90,555 27,524 74,699 22,522 Total net sales $ 235,774 $ 159,985 $ 184,694 $ 113,636 (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 $16.5 million and $15.4 million for the three months ended July 3, 2021 and July 4, 2020, respectively, were recognized over time. Nine Months Ended July 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 401,254 $ 343,383 $ 321,691 $ 277,710 Other product and service revenues (2) 268,930 82,227 237,673 75,174 Total net sales $ 670,184 $ 425,610 $ 559,364 $ 352,884 (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 $49.0 million and $46.3 million for the nine months ended July 3, 2021 and July 4, 2020, respectively, were recognized over time. Sales by market application and segment Three Months Ended July 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 142,012 $ 34,420 $ 123,635 $ 18,207 Precision manufacturing 12,805 90,657 7,581 74,156 Instrumentation 77,859 22,408 49,280 12,250 Aerospace and defense 3,098 12,500 4,198 9,023 Total net sales $ 235,774 $ 159,985 $ 184,694 $ 113,636 Nine Months Ended July 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 408,366 $ 85,191 $ 343,429 $ 50,726 Precision manufacturing 40,435 251,875 26,373 230,043 Instrumentation 212,213 61,614 174,304 47,814 Aerospace and defense 9,170 26,930 15,258 24,301 Total net sales $ 670,184 $ 425,610 $ 559,364 $ 352,884 See Note 18, "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 roll forward of our customer deposits and deferred revenue is as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Beginning balance (1) $ 56,339 $ 42,550 Additions to customer deposits and deferred revenue 164,357 137,747 Amount of customer deposits and deferred revenue recognized in income (2) (156,757) (126,501) Translation adjustments 70 260 Ending balance (3) $ 64,009 $ 54,056 (1) Beginning customer deposits and deferred revenue as of October 3, 2020 include $42,715 of current portion and $13,624 of long-term portion. 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 3, 2021 and July 4, 2020 was $65,509 and $48,674, respectively. (3) Ending customer deposits and deferred revenue as of July 3, 2021 include $49,203 of current portion and $14,806 of long-term portion. 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 3, 2021 (in thousands): Remainder of fiscal 2021 Thereafter Total Performance obligations as of July 3, 2021 $ 33,813 $ 30,196 $ 64,009

Business Combinations

Business Combinations	9 Months Ended
	Jul. 03, 2021
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS Merger Agreement On January 18, 2021, we entered into an Agreement and Plan of Merger with Lumentum Holdings Inc. ("Lumentum"), Cheetah Acquisition Sub, Inc. ("Lumentum Merger Sub I") and Cheetah Acquisition Sub LLC ("Lumentum Merger Sub II") (the "Original Lumentum Merger Agreement"), pursuant to which we agreed to be acquired for $100.00 in cash per Coherent share and 1.1851 shares of Lumentum common stock per Coherent share. In light of unsolicited proposals received from each of MKS Instruments, Inc. and II-VI Incorporated ("II-VI"), on March 9, 2021, we entered into an Amended and Restated Agreement and Plan of Merger with Lumentum, Lumentum Merger Sub I and Lumentum Merger Sub II (the "Amended Lumentum Agreement"), pursuant to which we agreed to be acquired for $175.00 in cash per Coherent share and 1.0109 shares of Lumentum common stock per Coherent share. On March 25, 2021, we terminated the Amended Lumentum Agreement and entered into an Agreement and Plan of Merger with II-VI and Watson Merger Sub Inc. ("II-VI Merger Sub") (the "II-VI Merger Agreement"), pursuant to which we agreed to be acquired for $220.00 in cash per Coherent share and 0.91 of a share of II-VI common stock per Coherent share. In connection with terminating the Amended Lumentum Agreement, we paid a termination fee of $217.6 million to Lumentum during our second quarter of fiscal 2021. The termination fee, in addition to other costs related to the merger agreements with Lumentum and II-VI, is included in merger and acquisition costs in our condensed consolidated statements of operations. Pursuant to the terms of the II-VI Merger Agreement, the acquisition of Coherent will be accomplished through a merger of II-VI Merger Sub with and into Coherent (the "Merger"), with Coherent surviving the Merger as a wholly owned subsidiary of II-VI. Pursuant to the terms of the II-VI Merger Agreement, and subject to the terms and conditions set forth therein, at the effective time of the Merger (the "Effective Time"), each share of the common stock of Coherent (the "Coherent Common Stock") issued and outstanding immediately prior to the Effective Time (other than (x) shares of Coherent Common Stock owned by II-VI, Coherent, or any direct or indirect wholly owned subsidiary of II-VI or Coherent or (y) shares of Coherent Common Stock owned by stockholders who have properly exercised and perfected appraisal rights under Delaware law, in each case, immediately prior to the Effective Time), will be cancelled and extinguished and automatically converted into the right to receive the following consideration: (A) $220.00 in cash, without interest, plus (B) 0.91 of a validly issued, fully paid and non-assessable share of the common stock of II-VI. The completion of Coherent's acquisition by II-VI is subject to customary closing conditions, including, among others, regulatory approvals in applicable jurisdictions outside the United States, including China, South Korea and Germany. Electro-Optics Technology On April 19, 2021, we acquired Electro-Optics Technology, Inc. ("EOT") for approximately $29.3 million, excluding transaction costs. EOT is a specialized U.S.-based components company, which we expect will enable us to vertically integrate and improve the performance of our directed energy amplifier technology. EOT has additional operations through a subsidiary in Germany. EOT will be included in our OEM Laser Sources segment. Our preliminary allocation of the purchase price is as follows (in thousands): Tangible assets: Cash $ 537 Accounts receivable 1,763 Inventories 5,269 Prepaid expenses and other assets 823 Property and equipment 18,713 Liabilities assumed (1,856) Deferred tax liabilities (4,009) Intangible assets: Existing technology 2,800 In-process research and development 300 Customer relationships 300 Trademarks 100 Backlog 100 Goodwill 4,507 Total $ 29,347 Results of operations for the business have been included in our condensed consolidated financial statements subsequent to the date of acquisition. 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 preliminary useful lives of 1 to 5 years. The fair value of the acquired intangibles was 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. We believe the amount of goodwill relates to several factors including: (1) potential buyer-specific synergies in connection with the development of new technologies primarily for the defense business; and (2) the potential to leverage our sales force to attract new customers and revenue and cross-sell to existing customers. None of the goodwill from this purchase is deductible for tax purposes. We expensed $0.2 million and $0.3 million, respectively, of acquisition-related costs as merger and acquisition costs in our condensed consolidated statements of operations in the three and nine months ended July 3, 2021.

Fair Values

Fair Values	9 Months Ended
	Jul. 03, 2021
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 3, 2021 and October 3, 2020, we had one investment carried on a cost basis. 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 3, 2021, the current and long-term portion of long-term obligations of $7.7 million and $437.3 million, respectively, are reported at amortized cost. As of October 3, 2020, the current and long-term portion of long-term obligations of $6.8 million and $411.1 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 3, 2021 and October 3, 2020 are summarized below (in thousands): Aggregate Fair Value Quoted Prices Significant Aggregate Fair Value Quoted Prices Significant July 3, 2021 October 3, 2020 (Level 1) (Level 2) (Level 1) (Level 2) Assets: Cash equivalents: Money market fund deposits $ 45,355 $ 45,355 $ — $ 36,646 $ 36,646 $ — Certificates of deposit 44,446 44,446 — 56,191 56,191 — Short-term investments: U.S. Treasury and agency obligations (1) 15,129 — 15,129 35,346 — 35,346 Prepaid and other assets: Foreign currency contracts (2) 940 — 940 812 — 812 Money market fund deposits — Deferred comp and supplemental plan (3) 492 492 — 203 203 — Mutual funds — Deferred comp and supplemental plan (3) 14,233 14,233 — 22,778 22,778 — Total $ 120,595 $ 104,526 $ 16,069 $ 151,976 $ 115,818 $ 36,158 Liabilities: Other current liabilities: Foreign currency contracts (2) (5,560) — (5,560) (2,811) — (2,811) Total $ 115,035 $ 104,526 $ 10,509 $ 149,165 $ 115,818 $ 33,347 ___________________________________________________ (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." (3) The fair value of mutual funds is determined based on quoted market prices. Securities traded on a national exchange are stated at the last reported sales price on the day of valuation; other securities traded in over-the-counter markets and listed securities for which no sale was reported on that date are stated as the last quoted bid price .

Short-Term Investments

Short-Term Investments	9 Months Ended
	Jul. 03, 2021
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 3, 2021 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 394,098 $ — $ — $ 394,098 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 15,030 $ 99 $ — $ 15,129 Total short-term investments $ 15,030 $ 99 $ — $ 15,129 October 3, 2020 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 440,258 $ — $ — $ 440,258 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 35,311 $ 36 $ (1) $ 35,346 Total short-term investments $ 35,311 $ 36 $ (1) $ 35,346

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Jul. 03, 2021
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. 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 3, 2021 October 3, 2020 July 3, 2021 October 3, 2020 Foreign currency hedge contracts Purchase $ 217,945 $ 169,206 $ (5,554) $ (1,802) Sell $ (58,983) $ (166,813) $ 934 $ (197) 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 3, 2021, we recognized losses of $0.5 million and $2.1 million, respectively, in other income (expense) for derivative instruments not designated as hedging instruments. 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. 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. 03, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	GOODWILL AND INTANGIBLE ASSETS During the quarter ended July 3, 2021, we noted no indications of impairment or triggering events to cause us to review goodwill for potential impairment. We will conduct our annual goodwill testing during the fourth fiscal quarter. See Note 8, "Goodwill and Intangible Assets" to our audited consolidated financial statements and notes thereto included in our Annual Report on Form 10-K for the year ended October 3, 2020 for discussion of the non-cash pre-tax charges we recorded in the quarter ended April 4, 2020 related to the goodwill, intangible assets, property, plant and equipment and ROU assets of the ILS reporting unit of $327.2 million, $33.9 million, $85.6 million and $1.8 million, respectively. The changes in the carrying amount of goodwill, all of which is in the OLS segment, for the period from October 3, 2020 to July 3, 2021 are as follows (in thousands): OEM Laser Sources Balance as of October 3, 2020 $ 101,317 Additions (see Note 4) 4,507 Translation adjustments 830 Balance as of July 3, 2021 $ 106,654 Components of our amortizable intangible assets are as follows (in thousands): July 3, 2021 October 3, 2020 Gross Accumulated Net Gross Accumulated Net Existing technology $ 40,232 $ (34,233) $ 5,999 $ 46,547 $ (37,630) $ 8,917 Customer relationships 22,498 (12,339) 10,159 24,388 (12,923) 11,465 Production know-how 2,300 (1,262) 1,038 2,300 (917) 1,383 In-process research & development 300 — 300 — — — Total $ 65,330 $ (47,834) $ 17,496 $ 73,235 $ (51,470) $ 21,765 For accounting purposes, when an intangible asset is fully amortized, it is removed from the disclosure schedule. Amortization expense for intangible assets for the nine months ended July 3, 2021 and July 4, 2020 was $8.2 million and $27.2 million, respectively. The change in the accumulated amortization also includes a $0.3 million increase and $1.8 million decrease of foreign exchange impact for the nine months ended July 3, 2021 and July 4, 2020, respectively. At July 3, 2021, estimated amortization expense for the remainder of fiscal 2021, the next five succeeding fiscal years and all fiscal years thereafter are as follows (in thousands): Estimated Amortization 2021 (remainder) $ 2,588 2022 4,013 2023 3,441 2024 2,658 2025 2,341 2026 2,001 Thereafter 154 Total (1) $ 17,196 (1) Excluding in-process research & development

Balance Sheet Details

Balance Sheet Details	9 Months Ended
	Jul. 03, 2021
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Details	BALANCE SHEET DETAILS Inventories consist of the following (in thousands): July 3, 2021 October 3, 2020 Purchased parts and assemblies $ 111,907 $ 116,957 Work-in-process 173,029 173,871 Finished goods 115,611 135,928 Total inventories $ 400,547 $ 426,756 Prepaid expenses and other assets consist of the following (in thousands): July 3, 2021 October 3, 2020 Prepaid and refundable income taxes $ 38,552 $ 50,548 Other taxes receivable 13,180 13,006 Prepaid expenses and other assets 36,012 24,696 Total prepaid expenses and other assets $ 87,744 $ 88,250 Other assets consist of the following (in thousands): July 3, 2021 October 3, 2020 Assets related to deferred compensation arrangements $ 35,050 $ 39,720 Deferred tax assets 146,316 102,028 Right of use assets, net - operating leases (See Note 11) 75,929 85,905 Right of use assets, net - finance leases (See Note 11) 101 656 Other assets 15,299 14,266 Total other assets $ 272,695 $ 242,575 Other current liabilities consist of the following (in thousands): July 3, 2021 October 3, 2020 Accrued payroll and benefits $ 95,265 $ 54,211 Operating lease liability, current (See Note 11) 15,721 15,366 Finance lease liability, current (See Note 11) 94 399 Deferred revenue 29,586 32,998 Warranty reserve 31,968 35,032 Accrued expenses and other 39,671 36,432 Customer deposits 19,617 9,717 Total other current liabilities $ 231,922 $ 184,155 Components of the reserve for warranty costs during the first nine months of fiscal 2021 and 2020 were as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Beginning balance $ 35,032 $ 36,460 Additions related to current period sales 23,473 28,669 Warranty costs incurred in the current period (27,059) (30,773) Accruals resulting from acquisitions 170 — Adjustments to accruals related to foreign exchange and other 352 615 Ending balance $ 31,968 $ 34,971 Other long-term liabilities consist of the following (in thousands): July 3, 2021 October 3, 2020 Long-term taxes payable $ 18,779 $ 15,374 Operating lease liability, long-term (See Note 11) 65,195 75,264 Finance lease liability, long-term (See Note 11) — 178 Deferred compensation 37,398 42,854 Defined benefit plan liabilities 46,619 45,810 Deferred tax liabilities 20,644 15,721 Deferred revenue 14,806 13,624 Asset retirement obligations liability 6,162 5,892 Other long-term liabilities 4,592 6,357 Total other long-term liabilities $ 214,195 $ 221,074

Borrowings

Borrowings	9 Months Ended
	Jul. 03, 2021
Debt Disclosure [Abstract]
Borrowings	BORROWINGS On December 21, 2020, Coherent LaserSystems GmbH & Co. KG entered into a loan agreement with Commerzbank for borrowings of up to 24.0 million Euros, to be drawn down by October 29, 2021, to finance a portion of the construction of a new facility in Germany. The term of the loan is 10 years and borrowings bear interest at 1.55% per annum. As of July 3, 2021, 24.0 million Euros have been withdrawn under this loan facility. The loan agreement contains customary affirmative loan covenants. We were in compliance with all covenants at July 3, 2021. 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 (in the first quarter of fiscal 2024), at which time all outstanding principal and accrued and unpaid interest on the Euro Term Loan must be repaid. As of July 3, 2021, the outstanding principal amount of the Euro Term Loan was 353.2 million Euros. As of July 3, 2021, 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 ("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 3, 2021, 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 3.25% 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 than or equal to 3.50 to 1.00. We were in compliance with all covenants at July 3, 2021. 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 $15.1 million as of July 3, 2021, of which $13.2 million was unused and available. These unsecured international credit facilities were used in Europe during the first nine months of fiscal 2021. As of July 3, 2021, we had utilized $1.9 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 3, 2021 October 3, 2020 Current portion of Euro Term Loan (1) $ 5,055 $ 4,970 1.3% Term loan due 2024 1,479 1,465 1.0% State of Connecticut term loan due 2023 385 382 Facility construction loan in Germany due 2030 811 — Line of credit borrowings 10,000 10,000 Total short-term borrowings and current portion of long-term obligations $ 17,730 $ 16,817 (1) Net of debt issuance costs of $2.9 million and $2.9 million at July 3, 2021 and October 3, 2020, respectively. Long-term obligations consist of the following (in thousands): July 3, 2021 October 3, 2020 Euro Term Loan due 2024 (1) $ 406,009 $ 406,099 1.3% Term loan due 2024 3,327 4,395 1.0% State of Connecticut term loan due 2023 357 646 Facility construction loan in Germany due 2030 27,576 — Total long-term obligations $ 437,269 $ 411,140 (1) Net of debt issuance costs of $3.8 million and $5.9 million at July 3, 2021 and October 3, 2020, respectively. Contractual maturities of our debt obligations, excluding line of credit borrowings, as of July 3, 2021 are as follows (in thousands): Amount 2021 (remainder) $ 2,447 2022 11,409 2023 12,909 2024 404,627 2025 3,244 Thereafter 17,033 Total $ 451,669

Leases

Leases	9 Months Ended
	Jul. 03, 2021
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 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. 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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Operating lease cost $ 5,165 $ 4,907 $ 15,941 $ 14,875 Variable lease cost 342 348 1,013 1,036 Short-term lease cost 15 123 38 383 Sublease income (2) (32) (7) (96) Total lease cost $ 5,520 $ 5,346 $ 16,985 $ 16,198 July 3, 2021 July 4, 2020 Weighted average remaining lease term 7.4 8.1 Weighted average discount rate 5.0 % 4.9 % Supplemental cash flow information related to leases are as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Operating cash outflows from operating leases $ 15,453 $ 14,672 ROU assets obtained in exchange for new operating lease liabilities 3,237 2,746 See Note 9, "Balance Sheet Details" for supplemental balance sheet information related to leases. As of July 3, 2021, maturities of our operating lease liabilities, which do not include short-term leases and variable lease payments, are as follows (in thousands): Operating Leases 2021 (remainder) $ 4,305 2022 18,650 2023 15,953 2024 12,480 2025 11,136 Thereafter 37,289 Total minimum lease payments 99,813 Amounts representing interest (18,897) Present value of total lease liabilities $ 80,916
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 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. 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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Operating lease cost $ 5,165 $ 4,907 $ 15,941 $ 14,875 Variable lease cost 342 348 1,013 1,036 Short-term lease cost 15 123 38 383 Sublease income (2) (32) (7) (96) Total lease cost $ 5,520 $ 5,346 $ 16,985 $ 16,198 July 3, 2021 July 4, 2020 Weighted average remaining lease term 7.4 8.1 Weighted average discount rate 5.0 % 4.9 % Supplemental cash flow information related to leases are as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Operating cash outflows from operating leases $ 15,453 $ 14,672 ROU assets obtained in exchange for new operating lease liabilities 3,237 2,746 See Note 9, "Balance Sheet Details" for supplemental balance sheet information related to leases. As of July 3, 2021, maturities of our operating lease liabilities, which do not include short-term leases and variable lease payments, are as follows (in thousands): Operating Leases 2021 (remainder) $ 4,305 2022 18,650 2023 15,953 2024 12,480 2025 11,136 Thereafter 37,289 Total minimum lease payments 99,813 Amounts representing interest (18,897) Present value of total lease liabilities $ 80,916

Stock-Based Compensation

Stock-Based Compensation	9 Months Ended
	Jul. 03, 2021
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 3, 2021 and July 4, 2020, respectively, were estimated using the following weighted-average assumptions: Employee Stock Purchase Plan Three Months Ended Nine Months Ended July 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Expected life in years 0.5 0.5 0.5 0.5 Volatility 54.0 % 63.7 % 50.5 % 53.0 % Risk-free interest rate 0.06 % 0.54 % 0.09 % 1.27 % Expected dividend yield — % — % — % — % Weighted average fair value per share $ 66.94 $ 43.35 $ 46.14 $ 43.81 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 3, 2021 and July 4, 2020 was determined using a Monte Carlo simulation model incorporating the following weighted average assumptions: Nine Months Ended July 3, 2021 July 4, 2020 Risk-free interest rate 0.19 % 0.90 % Volatility 51.7 % 50.4 % Weighted average fair value per share $ 119.54 $ 162.14 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, during fiscal 2020, we granted performance restricted stock unit awards 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 was capped at 100% of target. The total stock-based compensation of these awards was adjusted based on the level of achievement of free cash flow. These awards vested, in the three months ended January 2, 2021, at 100% of target. 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 3, 2021 and July 4, 2020 (in thousands): Three Months Ended Nine Months Ended July 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Cost of sales $ 1,720 $ 1,237 $ 5,981 $ 3,430 Research and development 1,100 1,469 3,329 2,924 Selling, general and administrative 7,328 11,680 22,115 24,722 Income tax benefit (1,185) (1,552) (4,103) (3,414) $ 8,963 $ 12,834 $ 27,322 $ 27,662 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 3, 2021, $1.7 million and $5.3 million of stock-based compensation cost, respectively, were capitalized as part of inventory for all stock plans, $1.7 million and $6.0 million, respectively, were amortized into cost of sales and $2.1 million remained in inventory at July 3, 2021. 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. At July 3, 2021, the total compensation cost related to unvested stock-based awards granted to employees under our stock plans but not yet recognized was approximately $56.9 million. We do not estimate forfeitures; we account for them as they occur. This cost will be amortized on a straight-line basis over a weighted-average period of approximately 1.5 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 2021 (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 October 3, 2020 419 $ 144.87 136 $ 177.54 Granted 294 136.46 64 119.43 Vested (1) (224) 144.89 (12) 118.45 Forfeited (9) 136.46 (30) 315.05 Nonvested stock at July 3, 2021 480 $ 139.86 158 $ 131.90 (1) Service-based restricted stock units vested during the fiscal year. Performance-based restricted stock units included at 100% of target goal. Under the terms of the market based awards, the recipient may earn between 0% and 200% of the award. Under the terms of the performance based awards based on free cash flow targets, the recipient may earn between 0% and 100% of the award.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Jul. 03, 2021
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 3, 2021, we did not have any material indemnification claims that were probable or reasonably possible. Legal Proceedings We are subject to legal 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 and purchase. 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. As previously disclosed in the Company's Quarterly Report on Form 10-Q for the quarterly period ended April 3, 2021, filed with the SEC on May 12, 2021, on April 28, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Southern District of New York against Coherent and its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the Registration Statement on Form S-4 (the "S-4") filed in connection with the Merger (Stein v. Coherent, Inc., et al., Case No. 1:21-cv-3775). Specifically, the complaint challenges the disclosures relating to management's financial projections and the analyses of the Company's financial advisors, BofA Securities, Inc. ("BofA Securities") and Credit Suisse Securities (USA) LLC ("Credit Suisse"). Among other things, the complaint alleges that the projections should have provided a reconciliation of non-GAAP financial measures to GAAP, and that the S-4 fails to disclose details about the bankers' precedent transactions analyses and DCF analyses. The complaint seeks, among other relief, a preliminary injunction until such time as corrective disclosures are issued. The case was voluntarily dismissed on June 18, 2021. As previously disclosed in the Company's Quarterly Report on Form 10-Q for the quarterly period ended April 3, 2021, filed with the SEC on May 12, 2021, on May 4, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the District of New Jersey against the Company and its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4 (Shirey v. Coherent, Inc., et al., Civil Action No. 2:21-cv-10698 (District of New Jersey, May 4, 2021)). Specifically, the complaint challenges the disclosures relating to the Company's and II-VI's financial projections, the analyses of the Company's financial advisors, BofA Securities and Credit Suisse, and potential conflicts of interest involving Credit Suisse. Among other things, the complaint alleges that the projections should have provided all line items used to calculate certain metrics and a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses, DCF analyses and price targets analyses and that there was insufficient disclosure regarding the relationships between Credit Suisse and either the Company or II-VI. The complaint seeks, among other relief, a preliminary injunction until such time as corrective disclosures are issued. The case was voluntarily dismissed on August 2, 2021. As previously disclosed in the Company's Quarterly Report on Form 10-Q for the quarterly period ended April 3, 2021, filed with the SEC on May 12, 2021, on May 4, 2021, a purported stockholder of the Company filed a complaint in the Southern District of New York against the Company, members of the Company's board of directors, II-VI and Watson Merger Sub Inc. alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4 (Diaz v. Coherent, Inc., et al., Case No. 1:21-cv-03990). Specifically, the complaint challenges the disclosures relating to the Company's and II-VI's financial projections, the analyses of the Company's financial advisors, BofA Securities and Credit Suisse, and potential conflicts of interest involving Credit Suisse. Among other things, the complaint alleges that the projections should have provided all line items used to calculate certain metrics and a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses, DCF analyses and price targets analyses and that there was insufficient disclosure regarding the relationships between Credit Suisse and either the Company or II-VI. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on June 24, 2021. As previously disclosed in the Company's Quarterly Report on Form 10-Q for the quarterly period ended April 3, 2021, filed with the SEC on May 12, 2021, on May 4, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Southern District of New York against the Company and members of its board of directors in the Southern District of New York alleging violations of the federal securities laws for misleading and incomplete disclosures in the Registration Statement on Form S-4/A (the “S-4/A”) filed in connection with the Merger (Costa v. Coherent, Inc., et al., Case No. 1:21-cv-04108). Specifically, the complaint challenges the disclosures relating to Coherent's and II-VI's financial projections and the analyses of the Company's financial advisors, BofA Securities and Credit Suisse. Among other things, the complaint alleges that the projections should have provided a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses and DCF analyses and that there was insufficient disclosure regarding the discretionary payment of $3.0 million to Credit Suisse at the closing of the merger. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on June 25, 2021. On June 1, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Southern District of New York against the Company and members of its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4/A (Wolf v. Coherent, Inc., et al., Case No. 1:21-cv-04848). Specifically, the complaint challenges the disclosures relating to the Company's and II-VI's financial projections, the analyses of the Company's financial advisors, BofA Securities and Credit Suisse, and potential conflicts of interest involving Credit Suisse. Among other things, the complaint alleges that the projections should have provided all line items used to calculate certain metrics and a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses, DCF analyses and price targets analyses and that there was insufficient disclosure regarding the relationships between Credit Suisse and either the Company or II-VI. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on June 24, 2021. On June 2, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the District of Delaware against the Company and members of its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4/A (Lawrence v. Coherent, Inc., et al., Case No. 1:21-cv-00808). Specifically, the complaint challenges the disclosures relating to Coherent's and II-VI's financial projections and the analyses of the Company's financial advisors, BofA Securities and Credit Suisse. Among other things, the complaint alleges that the projections should have provided a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses and DCF analyses, that there was insufficient disclosure regarding the discretionary payment of $3.0 million to Credit Suisse at the closing of the merger, and that there was insufficient disclosure regarding the calculation of BofA Securities' compensation. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on July 8, 2021. On June 2, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Northern District of California against the Company and members of its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4/A (Lawrence v. Coherent, Inc., et al., Case No. 5:21-cv-04193). Specifically, the complaint challenges the disclosures relating to Coherent's and II-VI's financial projections and the analyses of the Company's financial advisors, BofA Securities and Credit Suisse. Among other things, the complaint alleges that the projections should have provided a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses and DCF analyses, that there was insufficient disclosure regarding the discretionary payment of $3.0 million to Credit Suisse at the closing of the merger, and that there was insufficient disclosure regarding the calculation of BofA Securities' compensation. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on June 3, 2021. On June 3, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Northern District of California against the Company and members of its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4/A (Finger v. Coherent, Inc., et al., Case No. 5:21-cv-04217). Specifically, the complaint challenges the disclosures relating to Coherent's and II-VI's financial projections and the analyses of the Company's financial advisors, BofA Securities and Credit Suisse. Among other things, the complaint alleges that the projections should have provided a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses and DCF analyses, that there was insufficient disclosure regarding the discretionary payment of $3.0 million to Credit Suisse at the closing of the merger, and that there was insufficient disclosure regarding the calculation of BofA Securities' compensation. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on July 8, 2021. On June 10, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Eastern District of Pennsylvania against the Company and members of its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4/A (Waterman v. Coherent, Inc., et al., Case No. 2:21-cv-02623). Specifically, the complaint challenges the disclosures relating to the analyses of the Company's financial advisors, BofA Securities and Credit Suisse. Among other things, the complaint alleges that the S-4 fails to disclose details about the bankers' precedent transactions analyses, price targets analyses, and DCF analyses. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the director defendants to disseminate a true and non-misleading Registration Statement. The case was voluntarily dismissed on July 8, 2021. On June 11, 2021, a purported stockholder of the Company filed a complaint in the United States District Court for the Northern District of California against the Company and members of its board of directors alleging violations of the federal securities laws for misleading and incomplete disclosures in the S-4/A (Anderson v. Coherent, Inc., et al., Case No. 5:21-cv-04505). Specifically, the complaint challenges the disclosures relating to Coherent's and II-VI's financial projections and the analyses of the Company's financial advisors, BofA Securities and Credit Suisse. Among other things, the complaint alleges that the projections should have provided a reconciliation of non-GAAP financial measures to GAAP, that the S-4 fails to disclose details about the bankers' precedent transactions analyses and DCF analyses and that there was insufficient disclosure regarding the discretionary payment of $3.0 million to Credit Suisse at the closing of the merger. The complaint seeks, among other relief, a preliminary injunction to prevent further advancement of the transaction and a direction to the

Earnings Per Share

Earnings Per Share	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Weighted average shares outstanding—basic 24,435 24,159 24,362 24,075 Dilutive effect of employee stock awards 407 — — — Weighted average shares outstanding—diluted 24,842 24,159 24,362 24,075 Net income (loss) $ 30,262 $ (8,708) $ (127,809) $ (421,828) For the three months ended July 3, 2021 a total of 406,568 potentially dilutive securities have been excluded from the diluted share calculation as their effect was anti-dilutive. For the nine months ended July 3, 2021 and the three and nine months ended July 4, 2020, all potentially dilutive securities have been excluded from the diluted share calculation as we reported a net loss for those periods.

Other Income (Expense)

Other Income (Expense)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Foreign exchange loss $ (1,323) $ (1,623) $ (2,955) $ (3,316) Gain on deferred compensation investments, net 2,672 619 7,538 1,426 Other (164) 499 505 568 Other—net $ 1,185 $ (505) $ 5,088 $ (1,322)

Income Taxes

Income Taxes	9 Months Ended
	Jul. 03, 2021
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. Our effective tax rates on income before income taxes for the three months and loss before income taxes for the nine months ended July 3, 2021 were 22.1% and 12.0%, respectively. Our effective tax rates for the three months and nine months ended July 3, 2021 were unfavorably impacted primarily due to the impact of income subject to foreign tax rates that are higher than the U.S. tax rates, the deferred taxes on foreign earnings not considered permanently reinvested, stock-based compensation not deductible for tax purposes and limitations on the deductibility of compensation under Internal Revenue Code Section 162(m), partially offset by the benefit of federal research and development tax credits and our Singapore tax exemption. Additionally, our nine months effective tax rate was also unfavorably impacted due to the establishment of valuation allowances for certain foreign deferred tax assets in the first quarter of fiscal 2021.

Defined Benefit Plans

Defined Benefit Plans	9 Months Ended
	Jul. 03, 2021
Postemployment Benefits [Abstract]
Defined Benefits Plans	DEFINED BENEFIT PLANS For the three and nine months ended July 3, 2021, net periodic cost under our defined benefit plans was $0.8 million and $1.8 million, respectively. 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. 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. 03, 2021
Segment Reporting [Abstract]
Segment and Geographic Information	SEGMENT AND GEOGRAPHIC INFORMATION We are 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 machine tools primarily used for industrial laser materials processing, which serve important end markets like automotive, machine tools, consumer goods and medical device manufacturing as well as applications in aerospace and defense. 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 (loss) 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 (loss) 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 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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Net sales: OEM Laser Sources $ 235,774 $ 184,694 $ 670,184 $ 559,364 Industrial Lasers & Systems 159,985 113,636 425,610 352,884 Total net sales $ 395,759 $ 298,330 $ 1,095,794 $ 912,248 Income (loss) from operations: OEM Laser Sources $ 54,310 $ 42,853 $ 155,353 $ 126,030 Industrial Lasers & Systems 13,239 (20,571) 7,930 (512,716) Corporate and other (25,445) (23,456) (300,465) (53,209) Total income (loss) from operations 42,104 (1,174) (137,182) (439,895) Total other expense, net (3,277) (4,282) (8,092) (12,979) Income (loss) before income taxes $ 38,827 $ (5,456) $ (145,274) $ (452,874) 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 3, 2021 and July 4, 2020 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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 United States $ 88,370 $ 65,094 $ 242,638 $ 215,236 Foreign countries: South Korea 67,883 63,428 202,274 180,412 China 76,005 52,837 205,649 148,407 Japan 28,900 22,272 92,394 70,990 Asia-Pacific, other 38,589 24,090 97,320 67,889 Germany 38,815 28,650 104,385 90,485 Europe, other 36,624 27,917 99,692 95,130 Rest of World 20,573 14,042 51,442 43,699 Total foreign countries sales 307,389 233,236 853,156 697,012 Total sales $ 395,759 $ 298,330 $ 1,095,794 $ 912,248 Major Customers We had one customer during the three and nine months ended July 3, 2021 that accounted for 13.9% and 15.5% of net sales, respectively. This same customer accounted for 17.1% and 16.7% of net sales during the three and nine months ended July 4, 2020, respectively. This customer purchased primarily from our OLS segment.

Restructuring Charges

Restructuring Charges	9 Months Ended
	Jul. 03, 2021
Restructuring and Related Activities [Abstract]
Restructuring charges	RESTRUCTURING CHARGES In June 2019, we announced our plans to exit a portion of our high power fiber laser ("HPFL") business and consolidate all HPFL manufacturing and engineering functions in our Tampere, Finland facility by transferring certain HPFL activities from our Hamburg, Germany facility. 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 also vacated our leased facility in Santa Clara at the end of the lease term on July 31, 2020 and combined operations into our owned Santa Clara headquarters. We incurred costs in the second quarter of fiscal 2021of $0.1 million and for 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. In the fourth quarter of fiscal 2020, we began a restructuring program in our ILS segment which includes management reorganizations, the planned closure of certain manufacturing sites, and the right-sizing of global sales, service, order admin, marketing communication and certain administrative functions, among others. In the first, second and third quarters of fiscal 2021, we incurred costs of $5.4 million, $3.6 million and $0.2 million, respectively, primarily related to write-offs of excess inventory and accruals for vendor commitments, which are recorded in cost of sales, estimated severance and accelerated depreciation. 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 2021 and 2020 (in thousands): Severance Related Asset Write-Offs Other Total Balances, October 3, 2020 $ 2,611 $ — $ 230 $ 2,841 Provision 819 3,509 1,055 5,383 Payments and other (555) (3,509) (281) (4,345) Balances, January 2, 2021 2,875 — 1,004 3,879 Provision 2,775 558 325 3,658 Payments and other (2,032) (558) (623) (3,213) Balances, April 3, 2021 3,618 — 706 4,324 Provision (244) 318 86 160 Payments and other (756) (318) (282) (1,356) Balances, July 3, 2021 $ 2,618 $ — $ 510 $ 3,128 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 At July 3, 2021, $3.1 million of accrued severance related and other costs were included in other current liabilities. The severance, asset write-offs for inventory, accruals for vendor commitments, accelerated depreciation and other costs in the first, second and third quarters of fiscal 2021 primarily related to the restructuring program that began in the fourth quarter of fiscal 2020. 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 into our owned Santa Clara headquarters. By segment, $0.2 million and $9.1 million of restructuring costs were incurred in the ILS segment and $0.0 million and $0.1 million were incurred in the OLS segment in the three and nine months ended July 3, 2021, respectively. In the three and nine months ended July 4, 2020, $0.1 million and $1.3 million of the restructuring costs were incurred in the ILS segment and $0.4 million and $1.2 million were incurred in the OLS segment, respectively. Restructuring charges are recorded in cost of sales, research and development and selling, general and administrative expenses in our condensed consolidated statements of operations.

Recent Accounting Standards (Po

Recent Accounting Standards (Policies)	9 Months Ended
	Jul. 03, 2021
Accounting Policies [Abstract]
Recent Accounting Standards	Adoption of New Accounting Pronouncement In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("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. We adopted ASU 2016-13 in the first quarter of fiscal 2021 with no material impact to our condensed consolidated financial statements. With the adoption of Topic 326, we are now assessing whether unrealized losses have resulted from a credit loss or other factors. We believe none of our unrealized losses on available-for-sale investments were other-than temporary or were attributable to credit losses as of July 3, 2021 and October 3, 2020 . We review our available-for-sale investments on a quarterly basis to identify a potential other-than-temporary impairment. We also do not have an intent to sell our investments and would not be required to sell them before they recover. The adoption of Topic 326 did not significantly change our approach to the valuation of trade receivables. We determine whether there is an expected loss on our accounts receivable by reviewing all available data, including our customers' latest available financial statements, their credit standing and our historical collection experience, as well as current and future market and economic conditions. As of July 3, 2021 and October 3, 2020, the allowance for credit losses on our trade receivables was $4.9 million and $5.4 million, respectively. Recently Issued Accounting Pronouncements In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform ("Topic 848"). Topic 848 provides optional expedients and exceptions for applying U.S. GAAP to contracts, hedging relationships, and other transactions affected by the discontinuation of the London Interbank Offered Rate ("LIBOR") or by another reference rate expected to be discontinued. The guidance was effective beginning March 12, 2020 and can be applied prospectively through December 31, 2022. In January 2021, the FASB issued ASU 2021-01, "Reference Rate Reform - Scope," which clarified the scope and application of the original guidance. We will adopt these standards when LIBOR is discontinued and do not expect them to have a material impact on our consolidated financial statements or related disclosures.

Revenue Recognition (Tables)

Revenue Recognition (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 145,219 $ 132,461 $ 109,995 $ 91,114 Other product and service revenues (2) 90,555 27,524 74,699 22,522 Total net sales $ 235,774 $ 159,985 $ 184,694 $ 113,636 (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 $16.5 million and $15.4 million for the three months ended July 3, 2021 and July 4, 2020, respectively, were recognized over time. Nine Months Ended July 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Products (1) $ 401,254 $ 343,383 $ 321,691 $ 277,710 Other product and service revenues (2) 268,930 82,227 237,673 75,174 Total net sales $ 670,184 $ 425,610 $ 559,364 $ 352,884 (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 $49.0 million and $46.3 million for the nine months ended July 3, 2021 and July 4, 2020, respectively, were recognized over time. Sales by market application and segment Three Months Ended July 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 142,012 $ 34,420 $ 123,635 $ 18,207 Precision manufacturing 12,805 90,657 7,581 74,156 Instrumentation 77,859 22,408 49,280 12,250 Aerospace and defense 3,098 12,500 4,198 9,023 Total net sales $ 235,774 $ 159,985 $ 184,694 $ 113,636 Nine Months Ended July 3, 2021 July 4, 2020 OEM Laser Sources Industrial Lasers & Systems OEM Laser Sources Industrial Lasers & Systems Net sales: Microelectronics $ 408,366 $ 85,191 $ 343,429 $ 50,726 Precision manufacturing 40,435 251,875 26,373 230,043 Instrumentation 212,213 61,614 174,304 47,814 Aerospace and defense 9,170 26,930 15,258 24,301 Total net sales $ 670,184 $ 425,610 $ 559,364 $ 352,884
Summary of Customer Deposits and Deferred Revenue	A roll forward of our customer deposits and deferred revenue is as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Beginning balance (1) $ 56,339 $ 42,550 Additions to customer deposits and deferred revenue 164,357 137,747 Amount of customer deposits and deferred revenue recognized in income (2) (156,757) (126,501) Translation adjustments 70 260 Ending balance (3) $ 64,009 $ 54,056 (1) Beginning customer deposits and deferred revenue as of October 3, 2020 include $42,715 of current portion and $13,624 of long-term portion. 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 3, 2021 and July 4, 2020 was $65,509 and $48,674, respectively.
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 3, 2021 (in thousands): Remainder of fiscal 2021 Thereafter Total Performance obligations as of July 3, 2021 $ 33,813 $ 30,196 $ 64,009

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Jul. 03, 2021
Business Combinations [Abstract]
Schedule of Business Acquisitions, by Acquisition	Our preliminary allocation of the purchase price is as follows (in thousands): Tangible assets: Cash $ 537 Accounts receivable 1,763 Inventories 5,269 Prepaid expenses and other assets 823 Property and equipment 18,713 Liabilities assumed (1,856) Deferred tax liabilities (4,009) Intangible assets: Existing technology 2,800 In-process research and development 300 Customer relationships 300 Trademarks 100 Backlog 100 Goodwill 4,507 Total $ 29,347

Fair Values (Tables)

Fair Values (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 and October 3, 2020 are summarized below (in thousands): Aggregate Fair Value Quoted Prices Significant Aggregate Fair Value Quoted Prices Significant July 3, 2021 October 3, 2020 (Level 1) (Level 2) (Level 1) (Level 2) Assets: Cash equivalents: Money market fund deposits $ 45,355 $ 45,355 $ — $ 36,646 $ 36,646 $ — Certificates of deposit 44,446 44,446 — 56,191 56,191 — Short-term investments: U.S. Treasury and agency obligations (1) 15,129 — 15,129 35,346 — 35,346 Prepaid and other assets: Foreign currency contracts (2) 940 — 940 812 — 812 Money market fund deposits — Deferred comp and supplemental plan (3) 492 492 — 203 203 — Mutual funds — Deferred comp and supplemental plan (3) 14,233 14,233 — 22,778 22,778 — Total $ 120,595 $ 104,526 $ 16,069 $ 151,976 $ 115,818 $ 36,158 Liabilities: Other current liabilities: Foreign currency contracts (2) (5,560) — (5,560) (2,811) — (2,811) Total $ 115,035 $ 104,526 $ 10,509 $ 149,165 $ 115,818 $ 33,347 ___________________________________________________ (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." (3) The fair value of mutual funds is determined based on quoted market prices. Securities traded on a national exchange are stated at the last reported sales price on the day of valuation; other securities traded in over-the-counter markets and listed securities for which no sale was reported on that date are stated as the last quoted bid price .

Short-Term Investments (Tables)

Short-Term Investments (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 394,098 $ — $ — $ 394,098 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 15,030 $ 99 $ — $ 15,129 Total short-term investments $ 15,030 $ 99 $ — $ 15,129 October 3, 2020 Cost Basis Unrealized Unrealized Fair Value Cash and cash equivalents $ 440,258 $ — $ — $ 440,258 Short-term investments: Available-for-sale securities: U.S. Treasury and agency obligations $ 35,311 $ 36 $ (1) $ 35,346 Total short-term investments $ 35,311 $ 36 $ (1) $ 35,346

Derivative Instruments and He_2

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 October 3, 2020 July 3, 2021 October 3, 2020 Foreign currency hedge contracts Purchase $ 217,945 $ 169,206 $ (5,554) $ (1,802) Sell $ (58,983) $ (166,813) $ 934 $ (197)

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	9 Months Ended
	Jul. 03, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill by Segment	The changes in the carrying amount of goodwill, all of which is in the OLS segment, for the period from October 3, 2020 to July 3, 2021 are as follows (in thousands): OEM Laser Sources Balance as of October 3, 2020 $ 101,317 Additions (see Note 4) 4,507 Translation adjustments 830 Balance as of July 3, 2021 $ 106,654
Schedule of Components of Amortizable Intangible Assets	Components of our amortizable intangible assets are as follows (in thousands): July 3, 2021 October 3, 2020 Gross Accumulated Net Gross Accumulated Net Existing technology $ 40,232 $ (34,233) $ 5,999 $ 46,547 $ (37,630) $ 8,917 Customer relationships 22,498 (12,339) 10,159 24,388 (12,923) 11,465 Production know-how 2,300 (1,262) 1,038 2,300 (917) 1,383 In-process research & development 300 — 300 — — — Total $ 65,330 $ (47,834) $ 17,496 $ 73,235 $ (51,470) $ 21,765
Schedule of Estimated Amortization Expense	At July 3, 2021, estimated amortization expense for the remainder of fiscal 2021, the next five succeeding fiscal years and all fiscal years thereafter are as follows (in thousands): Estimated Amortization 2021 (remainder) $ 2,588 2022 4,013 2023 3,441 2024 2,658 2025 2,341 2026 2,001 Thereafter 154 Total (1) $ 17,196 (1) Excluding in-process research & development

Balance Sheet Details (Tables)

Balance Sheet Details (Tables)	9 Months Ended
	Jul. 03, 2021
Balance Sheet Related Disclosures [Abstract]
Schedule of Inventories	Inventories consist of the following (in thousands): July 3, 2021 October 3, 2020 Purchased parts and assemblies $ 111,907 $ 116,957 Work-in-process 173,029 173,871 Finished goods 115,611 135,928 Total inventories $ 400,547 $ 426,756
Schedule of Prepaid Expenses and Other Assets	Prepaid expenses and other assets consist of the following (in thousands): July 3, 2021 October 3, 2020 Prepaid and refundable income taxes $ 38,552 $ 50,548 Other taxes receivable 13,180 13,006 Prepaid expenses and other assets 36,012 24,696 Total prepaid expenses and other assets $ 87,744 $ 88,250
Schedule of Other Assets	Other assets consist of the following (in thousands): July 3, 2021 October 3, 2020 Assets related to deferred compensation arrangements $ 35,050 $ 39,720 Deferred tax assets 146,316 102,028 Right of use assets, net - operating leases (See Note 11) 75,929 85,905 Right of use assets, net - finance leases (See Note 11) 101 656 Other assets 15,299 14,266 Total other assets $ 272,695 $ 242,575
Schedule of Other Current Liabilities	Other current liabilities consist of the following (in thousands): July 3, 2021 October 3, 2020 Accrued payroll and benefits $ 95,265 $ 54,211 Operating lease liability, current (See Note 11) 15,721 15,366 Finance lease liability, current (See Note 11) 94 399 Deferred revenue 29,586 32,998 Warranty reserve 31,968 35,032 Accrued expenses and other 39,671 36,432 Customer deposits 19,617 9,717 Total other current liabilities $ 231,922 $ 184,155
Schedule of Components of Reserve for Warranty Costs	Components of the reserve for warranty costs during the first nine months of fiscal 2021 and 2020 were as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Beginning balance $ 35,032 $ 36,460 Additions related to current period sales 23,473 28,669 Warranty costs incurred in the current period (27,059) (30,773) Accruals resulting from acquisitions 170 — Adjustments to accruals related to foreign exchange and other 352 615 Ending balance $ 31,968 $ 34,971
Schedule of Other Long-Term Liabilities	Other long-term liabilities consist of the following (in thousands): July 3, 2021 October 3, 2020 Long-term taxes payable $ 18,779 $ 15,374 Operating lease liability, long-term (See Note 11) 65,195 75,264 Finance lease liability, long-term (See Note 11) — 178 Deferred compensation 37,398 42,854 Defined benefit plan liabilities 46,619 45,810 Deferred tax liabilities 20,644 15,721 Deferred revenue 14,806 13,624 Asset retirement obligations liability 6,162 5,892 Other long-term liabilities 4,592 6,357 Total other long-term liabilities $ 214,195 $ 221,074

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 October 3, 2020 Current portion of Euro Term Loan (1) $ 5,055 $ 4,970 1.3% Term loan due 2024 1,479 1,465 1.0% State of Connecticut term loan due 2023 385 382 Facility construction loan in Germany due 2030 811 — Line of credit borrowings 10,000 10,000 Total short-term borrowings and current portion of long-term obligations $ 17,730 $ 16,817 (1) Net of debt issuance costs of $2.9 million and $2.9 million at July 3, 2021 and October 3, 2020, respectively.
Schedule of Long-term Debt	Long-term obligations consist of the following (in thousands): July 3, 2021 October 3, 2020 Euro Term Loan due 2024 (1) $ 406,009 $ 406,099 1.3% Term loan due 2024 3,327 4,395 1.0% State of Connecticut term loan due 2023 357 646 Facility construction loan in Germany due 2030 27,576 — Total long-term obligations $ 437,269 $ 411,140 (1) Net of debt issuance costs of $3.8 million and $5.9 million at July 3, 2021 and October 3, 2020, respectively.
Schedule of Maturities of Long-term Debt	Contractual maturities of our debt obligations, excluding line of credit borrowings, as of July 3, 2021 are as follows (in thousands): Amount 2021 (remainder) $ 2,447 2022 11,409 2023 12,909 2024 404,627 2025 3,244 Thereafter 17,033 Total $ 451,669

Leases (Tables)

Leases (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Operating lease cost $ 5,165 $ 4,907 $ 15,941 $ 14,875 Variable lease cost 342 348 1,013 1,036 Short-term lease cost 15 123 38 383 Sublease income (2) (32) (7) (96) Total lease cost $ 5,520 $ 5,346 $ 16,985 $ 16,198 July 3, 2021 July 4, 2020 Weighted average remaining lease term 7.4 8.1 Weighted average discount rate 5.0 % 4.9 % Supplemental cash flow information related to leases are as follows (in thousands): Nine Months Ended July 3, 2021 July 4, 2020 Operating cash outflows from operating leases $ 15,453 $ 14,672 ROU assets obtained in exchange for new operating lease liabilities 3,237 2,746
Operating Lease maturity	As of July 3, 2021, maturities of our operating lease liabilities, which do not include short-term leases and variable lease payments, are as follows (in thousands): Operating Leases 2021 (remainder) $ 4,305 2022 18,650 2023 15,953 2024 12,480 2025 11,136 Thereafter 37,289 Total minimum lease payments 99,813 Amounts representing interest (18,897) Present value of total lease liabilities $ 80,916

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 and July 4, 2020, respectively, were estimated using the following weighted-average assumptions: Employee Stock Purchase Plan Three Months Ended Nine Months Ended July 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Expected life in years 0.5 0.5 0.5 0.5 Volatility 54.0 % 63.7 % 50.5 % 53.0 % Risk-free interest rate 0.06 % 0.54 % 0.09 % 1.27 % Expected dividend yield — % — % — % — % Weighted average fair value per share $ 66.94 $ 43.35 $ 46.14 $ 43.81
Schedule of Weighted Average Assumptions of Performance Units	The weighted average fair value for the performance units granted for the nine months ended July 3, 2021 and July 4, 2020 was determined using a Monte Carlo simulation model incorporating the following weighted average assumptions: Nine Months Ended July 3, 2021 July 4, 2020 Risk-free interest rate 0.19 % 0.90 % Volatility 51.7 % 50.4 % Weighted average fair value per share $ 119.54 $ 162.14
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 3, 2021 and July 4, 2020 (in thousands): Three Months Ended Nine Months Ended July 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Cost of sales $ 1,720 $ 1,237 $ 5,981 $ 3,430 Research and development 1,100 1,469 3,329 2,924 Selling, general and administrative 7,328 11,680 22,115 24,722 Income tax benefit (1,185) (1,552) (4,103) (3,414) $ 8,963 $ 12,834 $ 27,322 $ 27,662
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 2021 (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 October 3, 2020 419 $ 144.87 136 $ 177.54 Granted 294 136.46 64 119.43 Vested (1) (224) 144.89 (12) 118.45 Forfeited (9) 136.46 (30) 315.05 Nonvested stock at July 3, 2021 480 $ 139.86 158 $ 131.90 (1) Service-based restricted stock units vested during the fiscal year. Performance-based restricted stock units included at 100% of target goal. Under the terms of the market based awards, the recipient may earn between 0% and 200% of the award. Under the terms of the performance based awards based on free cash flow targets, the recipient may earn between 0% and 100% of the award.

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Weighted average shares outstanding—basic 24,435 24,159 24,362 24,075 Dilutive effect of employee stock awards 407 — — — Weighted average shares outstanding—diluted 24,842 24,159 24,362 24,075 Net income (loss) $ 30,262 $ (8,708) $ (127,809) $ (421,828)

Other Income (Expense) (Tables)

Other Income (Expense) (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Foreign exchange loss $ (1,323) $ (1,623) $ (2,955) $ (3,316) Gain on deferred compensation investments, net 2,672 619 7,538 1,426 Other (164) 499 505 568 Other—net $ 1,185 $ (505) $ 5,088 $ (1,322)

Segment and Geographic Inform_2

Segment and Geographic Information (Tables)	9 Months Ended
	Jul. 03, 2021
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 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 Net sales: OEM Laser Sources $ 235,774 $ 184,694 $ 670,184 $ 559,364 Industrial Lasers & Systems 159,985 113,636 425,610 352,884 Total net sales $ 395,759 $ 298,330 $ 1,095,794 $ 912,248 Income (loss) from operations: OEM Laser Sources $ 54,310 $ 42,853 $ 155,353 $ 126,030 Industrial Lasers & Systems 13,239 (20,571) 7,930 (512,716) Corporate and other (25,445) (23,456) (300,465) (53,209) Total income (loss) from operations 42,104 (1,174) (137,182) (439,895) Total other expense, net (3,277) (4,282) (8,092) (12,979) Income (loss) before income taxes $ 38,827 $ (5,456) $ (145,274) $ (452,874) Sales to unaffiliated customers are as follows (in thousands): Three Months Ended Nine Months Ended SALES July 3, 2021 July 4, 2020 July 3, 2021 July 4, 2020 United States $ 88,370 $ 65,094 $ 242,638 $ 215,236 Foreign countries: South Korea 67,883 63,428 202,274 180,412 China 76,005 52,837 205,649 148,407 Japan 28,900 22,272 92,394 70,990 Asia-Pacific, other 38,589 24,090 97,320 67,889 Germany 38,815 28,650 104,385 90,485 Europe, other 36,624 27,917 99,692 95,130 Rest of World 20,573 14,042 51,442 43,699 Total foreign countries sales 307,389 233,236 853,156 697,012 Total sales $ 395,759 $ 298,330 $ 1,095,794 $ 912,248

Restructuring Charges (Tables)

Restructuring Charges (Tables)	9 Months Ended
	Jul. 03, 2021
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 2021 and 2020 (in thousands): Severance Related Asset Write-Offs Other Total Balances, October 3, 2020 $ 2,611 $ — $ 230 $ 2,841 Provision 819 3,509 1,055 5,383 Payments and other (555) (3,509) (281) (4,345) Balances, January 2, 2021 2,875 — 1,004 3,879 Provision 2,775 558 325 3,658 Payments and other (2,032) (558) (623) (3,213) Balances, April 3, 2021 3,618 — 706 4,324 Provision (244) 318 86 160 Payments and other (756) (318) (282) (1,356) Balances, July 3, 2021 $ 2,618 $ — $ 510 $ 3,128 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

Recent Accounting Standards (De

Recent Accounting Standards (Details) - USD ($) $ in Millions	Jul. 03, 2021	Oct. 03, 2020
Accounting Policies [Abstract]
Allowance for Doubtful Accounts, Premiums and Other Receivables	$ 4.9	$ 5.4

Revenue Recognition Disaggregat

Revenue Recognition Disaggregation of revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Disaggregation of Revenue [Line Items]
Net sales	$ 395,759	$ 298,330	$ 1,095,794	$ 912,248
OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	235,774	184,694	670,184	559,364
Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	159,985	113,636	425,610	352,884
Products | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	145,219	109,995	401,254	321,691
Products | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	132,461	91,114	343,383	277,710
Other products and services revenues | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	90,555	74,699	268,930	237,673
Other products and services revenues | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	27,524	22,522	82,227	75,174
Sales of spare parts
Disaggregation of Revenue [Line Items]
Net sales	16,500	15,400	49,000	46,300
Microelectronics | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	142,012	123,635	408,366	343,429
Microelectronics | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	34,420	18,207	85,191	50,726
Precision manufacturing | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	12,805	7,581	40,435	26,373
Precision manufacturing | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	90,657	74,156	251,875	230,043
Instrumentation | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	77,859	49,280	212,213	174,304
Instrumentation | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	22,408	12,250	61,614	47,814
Aerospace and defense | OEM Laser Sources
Disaggregation of Revenue [Line Items]
Net sales	3,098	4,198	9,170	15,258
Aerospace and defense | Industrial Lasers & Systems
Disaggregation of Revenue [Line Items]
Net sales	$ 12,500	$ 9,023	$ 26,930	$ 24,301

Revenue Recognition Contract ba

Revenue Recognition Contract balances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020	Oct. 03, 2020	Sep. 28, 2019
Change in Contract with Customer, Liability [Abstract]
Contract with customer, beginning balance			$ 56,339	$ 42,550
Additions to customer deposits and deferred revenue			164,357	137,747
Amount of customer deposits and deferred revenue recognized in income	$ 65,509	$ 48,674	(156,757)	(126,501)
Translation adjustments			70	260
Contract with customer, ending balance	64,009	54,056	64,009	54,056
Customer deposits	49,203	41,329	49,203	41,329	$ 42,715	$ 34,538
Customer deposits and deferred revenue, noncurrent	$ 14,806	$ 12,727	$ 14,806	$ 12,727	$ 13,624	$ 8,012

Revenue Recognition Performance

Revenue Recognition Performance Obligations (Details) $ in Thousands	Jul. 03, 2021USD ($)
Revenue from Contract with Customer [Abstract]
Performance Obligations	$ 64,009
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-07-04
Revenue from Contract with Customer [Abstract]
Performance Obligations	$ 33,813
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]: 2021-10-03
Revenue from Contract with Customer [Abstract]
Performance Obligations	$ 30,196
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Performance obligation period	1 year

Business Combinations (Details)

Business Combinations (Details) - USD ($)	Apr. 19, 2021	Mar. 25, 2021	Mar. 09, 2021	Jan. 18, 2021	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020	Oct. 03, 2020
Business Acquisition [Line Items]
Goodwill					$ 106,654,000		$ 106,654,000		$ 101,317,000
Merger and acquisition costs					2,578,000	$ 0	234,574,000	$ 0
Lumentum Holdings Inc.
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross			$ 175	$ 100
Business Acquisition, Share Price			$ 1.0109	$ 1.1851
Merger and acquisition costs		$ 217,600,000
II-VI Incorporated
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross		$ 220
Business Acquisition, Share Price		$ 0.91
Electro-optics Technology, Inc.
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 29,300,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	537,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	1,763,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	5,269,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Prepaid Expense and Other Assets	823,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	18,713,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities	(1,856,000)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities	(4,009,000)
Goodwill	4,507,000
Total	29,347,000
Merger and acquisition costs					$ 200,000		$ 300,000
Electro-optics Technology, Inc. | Minimum
Business Acquisition [Line Items]
Useful life					1 year
Electro-optics Technology, Inc. | Maximum
Business Acquisition [Line Items]
Useful life					5 years
Electro-optics Technology, Inc. | Developed Technology Rights
Business Acquisition [Line Items]
Intangible assets	2,800,000
Electro-optics Technology, Inc. | In Process Research and Development
Business Acquisition [Line Items]
Intangible assets	300,000
Electro-optics Technology, Inc. | Customer-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	300,000
Electro-optics Technology, Inc. | Marketing-Related Intangible Assets
Business Acquisition [Line Items]
Intangible assets	100,000
Electro-optics Technology, Inc. | Order or Production Backlog [Member]
Business Acquisition [Line Items]
Intangible assets	$ 100,000

Fair Values (Details)

Fair Values (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Oct. 03, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Current portion of long term obligation, amortized cost	$ 7,700	$ 6,800
Long-term obligations	437,269	411,140
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	14,233	22,778
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	14,233	22,778
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	104,526	115,818
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	16,069	36,158
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	120,595	151,976
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	104,526	115,818
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	10,509	33,347
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	115,035	149,165
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	45,355	36,646
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	45,355	36,646
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	492	203
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	492	203
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	44,446	56,191
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	44,446	56,191
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	15,129	35,346
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	15,129	35,346
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	940	812
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	940	812
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	(5,560)	(2,811)
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	$ (5,560)	$ (2,811)

Short-Term Investments (Details

Short-Term Investments (Details) - USD ($) $ in Thousands	Jul. 03, 2021	Oct. 03, 2020	Jul. 04, 2020
Schedule of Investments [Line Items]
Cash and cash equivalents, Cost Basis	$ 394,098	$ 440,258
Cash and cash equivalent, Unrealized Gains	0	0
Cash and cash equivalent, Unrealized Losses	0	0
Cash and cash equivalents	394,098	440,258	$ 378,992
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain (Loss), before Tax	100	100
Short-term investments:
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	15,030	35,311
Available-for-sale securities, Unrealized Gains	99	36
Available-for-sale securities, Unrealized Losses	0	(1)
Available-for-sale securities: Fair Value	15,129	35,346
Short-term investments: | U.S. Treasury and agency obligations
Schedule of Investments [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	15,030	35,311
Available-for-sale securities, Unrealized Gains	99	36
Available-for-sale securities, Unrealized Losses	0	(1)
Available-for-sale securities: Fair Value	$ 15,129	$ 35,346

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. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020	Oct. 03, 2020
Derivatives, Fair Value [Line Items]
Loss on derivatives	$ 500	$ 1,100	$ 2,100	$ 1,200
Derivatives not designated as hedging instruments | Purchase | Euro
Derivatives, Fair Value [Line Items]
Derivative asset, notional amount	217,945		217,945		$ 169,206
Derivative asset, Fair Value	(5,554)		(5,554)		(1,802)
Derivatives not designated as hedging instruments | Sell | Euro
Derivatives, Fair Value [Line Items]
Derivative liability, notional amount	(58,983)		(58,983)		(166,813)
Derivative liability, Fair Value	$ 934		$ 934		$ (197)

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. 03, 2021	Jul. 04, 2020
Goodwill [Line Items]
Impairment charges		$ 0	$ (327,203)
Industrial Lasers & Systems
Goodwill [Line Items]
Impairment charges	$ (327,200)
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	3 Months Ended	9 Months Ended
	Apr. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Goodwill [Roll Forward]
Goodwill, beginning of period		$ 101,317
Impairment charges		0	$ (327,203)
Goodwill, end of period		106,654
OEM Laser Sources
Goodwill [Roll Forward]
Goodwill, beginning of period		101,317
Translation adjustments		830
Goodwill, end of period		106,654
Goodwill, Acquired During Period		$ 4,507
Industrial Lasers & Systems
Goodwill [Roll Forward]
Impairment charges	$ (327,200)

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Oct. 03, 2020
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	$ 65,330		$ 73,235
Accumulated Amortization	(47,834)		(51,470)
Net including IPRD	17,496		21,765
Amortization expense for intangible assets	(8,174)	$ (27,166)
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2021 (remainder)	2,588
2022	4,013
2023	3,441
2024	2,658
2025	2,341
2026	2,001
Thereafter	154
Net excluding IPRD	17,196
Existing technology
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	40,232		46,547
Accumulated Amortization	(34,233)		(37,630)
Net including IPRD	5,999		8,917
Customer relationships
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	22,498		24,388
Accumulated Amortization	(12,339)		(12,923)
Net including IPRD	10,159		11,465
Production know-how
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	2,300		2,300
Accumulated Amortization	(1,262)		(917)
Net including IPRD	1,038		$ 1,383
Foreign exchange
Finite-Lived Intangible Assets, Net [Abstract]
Amortization expense for intangible assets	300	$ (1,800)
Research and Development Asset, Transaction [Domain]
Finite-Lived Intangible Assets, Net [Abstract]
Gross Carrying Amount	300
Net including IPRD	$ 300

Balance Sheet Details (Details)

Balance Sheet Details (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Oct. 03, 2020
Inventory, Net [Abstract]
Purchased parts and assemblies	$ 111,907		$ 116,957
Work-in-process	173,029		173,871
Finished goods	115,611		135,928
Total inventories	400,547		426,756
Prepaid Expense and Other Assets, Current [Abstract]
Prepaid and refundable income taxes	38,552		50,548
Other taxes receivable	13,180		13,006
Prepaid expenses and other assets	36,012		24,696
Total prepaid expenses and other assets	87,744		88,250
Other Assets, Noncurrent Disclosure [Abstract]
Assets related to deferred compensation arrangements	35,050		39,720
Deferred tax assets	146,316		102,028
Right of use assets, net - operating leases (See Note 11)	75,929		85,905
Right of use assets, net - finance leases (See Note 11)	101		656
Other assets	15,299		14,266
Total other assets	272,695		242,575
Other Liabilities, Current [Abstract]
Accrued payroll and benefits	95,265		54,211
Operating lease liability, current (See Note 11)	15,721		15,366
Finance lease liability, current (See Note 11)	94		399
Deferred revenue	29,586		32,998
Warranty reserve	31,968		35,032
Accrued expenses and other	39,671		36,432
Customer deposits	19,617		9,717
Total other current liabilities	231,922		184,155
Movement in Standard and Extended Product Warranty Accrual, Increase (Decrease) [Roll Forward]
Beginning balance	35,032	$ 36,460
Additions related to current period sales	23,473	28,669
Warranty costs incurred in the current period	(27,059)	(30,773)
Accruals resulting from acquisitions	170	0
Adjustments to accruals related to foreign exchange and other	352	615
Ending balance	31,968	$ 34,971
Other Liabilities, Noncurrent [Abstract]
Long-term taxes payable	18,779		15,374
Operating lease liability, long-term (See Note 11)	65,195		75,264
Finance lease liability, long-term (See Note 11)	0		178
Deferred compensation	37,398		42,854
Defined benefit plan liabilities	46,619		45,810
Deferred tax liabilities	20,644		15,721
Deferred revenue	14,806		13,624
Asset retirement obligations liability	6,162		5,892
Other long-term liabilities	4,592		6,357
Total other long-term liabilities	$ 214,195		$ 221,074

Borrowings (Details)

Borrowings (Details) € in Millions	Dec. 21, 2020EUR (€)	May 08, 2018	Mar. 31, 2018USD ($)	Sep. 29, 2018USD ($)	Jul. 03, 2021EUR (€)	Jul. 03, 2021USD ($)	Nov. 07, 2016EUR (€)	Nov. 07, 2016USD ($)
Debt [Line Items]
Additional sources of cash available						$ 15,100,000
Debt instrument, unused borrowing capacity, amount						13,200,000
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
Loan Agreement December 21 2020 | Commerzbank | Foreign Line of Credit
Debt [Line Items]
Lines of credit, maximum borrowing capacity | €	€ 24
Debt Instrument, Interest Rate, Stated Percentage	1.55%
Amounts drawn upon line of credit | €					€ 24
Debt Instrument, Term	10 years
Euro
Debt [Line Items]
Domestic line of credit drawn | €							€ 10
Line of Credit, Foreign | Europe, other
Debt [Line Items]
Amounts drawn upon line of credit						1,900,000
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 | €					€ 353.2
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							0.0325	0.0325
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

Borrowings - Borrowings obligat

Borrowings - Borrowings obligation table (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Jul. 03, 2021	Oct. 03, 2020	Mar. 31, 2018
Short-term Debt [Line Items]
Total short-term borrowings and current portion of long-term obligations	$ 17,730	$ 16,817
Interest rate For 1.3% Term loan due 2024	1.30%
Interest rate of state of Connecticut	1.00%
Euro term loan
Short-term Debt [Line Items]
Debt issuance cost for long term portion of the euro term loan	$ 3,800	5,900
Debt Issuance Costs, Gross			$ 500
Euro term loan
Short-term Debt [Line Items]
Debt issuance cost for short term euro term loan	2,900	2,900
Short-term Debt
Short-term Debt [Line Items]
Euro Term Loan due 2024	5,055	4,970
1.3% Term loan due 2024	1,479	1,465
1.0% State of Connecticut term loan due 2023	385	382
Line of credit borrowings	10,000	10,000
Total short-term borrowings and current portion of long-term obligations	17,730	16,817
Facility construction loan in Germany due 2030	811	0
Long-term Debt
Short-term Debt [Line Items]
Euro Term Loan due 2024	406,009	406,099
1.3% Term loan due 2024	3,327	4,395
1.0% State of Connecticut term loan due 2023	357	646
Long-term Debt	437,269	411,140
Facility construction loan in Germany due 2030 -LT	$ 27,576	$ 0

Borrowings - Debt Maturity Tabl

Borrowings - Debt Maturity Table (Details) $ in Thousands	Jul. 03, 2021USD ($)
Debt Disclosure [Abstract]
2021 (remainder)	$ 2,447
2022	11,409
2023	12,909
2024	404,627
Long-Term Debt, Maturity, Year Five	3,244
Long-Term Debt, Maturity, after Year Five	17,033
Total contractual obligation due amount	$ 451,669

Leases - Additional Information

Leases - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended
	Apr. 04, 2020	Jul. 03, 2021
Minimum
Lessee, Lease, Description [Line Items]
Finance lease arrangements		3 years
Maximum
Lessee, Lease, Description [Line Items]
Finance lease arrangements		9 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) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Leases [Abstract]
Operating lease cost	$ 5,165	$ 4,907	$ 15,941	$ 14,875
Variable lease cost	342	348	1,013	1,036
Short-term lease cost	15	123	38	383
Sublease income	(2)	(32)	(7)	(96)
Total lease cost	$ 5,520	$ 5,346	$ 16,985	$ 16,198
Weighted average remaining lease term	7 years 4 months 24 days	8 years 1 month 6 days	7 years 4 months 24 days	8 years 1 month 6 days
Weighted average discount rate	5.00%	4.90%	5.00%	4.90%

Leases - Supplemental Cash Flow

Leases - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020
Leases [Abstract]
Operating cash outflows from operating leases	$ 15,453	$ 14,672
ROU assets obtained in exchange for new operating lease liabilities	$ 3,237	$ 2,746

Leases - Schedule of Maturities

Leases - Schedule of Maturities After Adoption of ASC 842 (Details) $ in Thousands	Jul. 03, 2021USD ($)
Operating Leases
2021 (remainder)	$ 4,305
2022	18,650
2023	15,953
2024	12,480
2025	11,136
Thereafter	37,289
Total minimum lease payments	99,813
Amounts representing interest	(18,897)
Present value of total lease liabilities	$ 80,916

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Stock Compensation (Details) - $ / shares	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
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	54.00%	63.70%	50.50%	53.00%
Risk-free interest rate	0.06%	0.54%	0.09%	1.27%
Expected dividend yield	0.00%	0.00%	0.00%	0.00%
Weighted average fair value per share	$ 66.94	$ 43.35	$ 46.14	$ 43.81
Performance restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions and Methodology [Abstract]
Volatility			51.70%	50.40%
Risk-free interest rate			0.19%	0.90%
Weighted average fair value per share			$ 119.54	$ 162.14

Stock-Based Compensation - Stoc

Stock-Based Compensation - Stock Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	$ 8,963	$ 12,834	$ 27,322	$ 27,662
Capitalized share-based compensation costs	1,700	2,100	5,300	4,300
Amortization of capitalized share-based compensation expenses	1,700	1,200	6,000	3,400
Total compensation cost, unvested stock-based awards granted but not yet recognized	56,900		$ 56,900
Total compensation cost, weighted-average period of amortization (in years)			1 year 6 months
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	2,100	2,400	$ 2,100	2,400
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	1,720	1,237	5,981	3,430
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	1,100	1,469	3,329	2,924
Selling, general and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Allocated stock-based compensation expense	7,328	11,680	22,115	24,722
Income tax benefit
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Income tax benefit	$ (1,185)	$ (1,552)	$ (4,103)	$ (3,414)

Stock-Based Compensation - St_2

Stock-Based Compensation - Stock Options and Awards Activity (Details) shares in Thousands	9 Months Ended
	Jul. 03, 2021$ / sharesshares
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) | shares	419
Granted (in shares) | shares	294
Vested (in shares) | shares	(224)
Forfeited (in shares) | shares	(9)
Nonvested stock, end of period (in shares) | shares	480
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) | $ / shares	$ 144.87
Granted (in dollars per share) | $ / shares	136.46
Vested (in dollars per share) | $ / shares	144.89
Forfeited (in dollars per share) | $ / shares	136.46
Nonvested stock, end of period (in dollars per share) | $ / shares	$ 139.86
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) | shares	136
Granted (in shares) | shares	64
Vested (in shares) | shares	(12)
Forfeited (in shares) | shares	(30)
Nonvested stock, end of period (in shares) | shares	158
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) | $ / shares	$ 177.54
Granted (in dollars per share) | $ / shares	119.43
Vested (in dollars per share) | $ / shares	118.45
Forfeited (in dollars per share) | $ / shares	315.05
Nonvested stock, end of period (in dollars per share) | $ / shares	$ 131.90
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%
Performance Shares | Minimum
Restricted Stock Units and Awards [Abstract]
Percentage of performance-based awards earned by recipient	0.00%
Performance Shares | Maximum
Restricted Stock Units and Awards [Abstract]
Percentage of performance-based awards earned by recipient	100.00%

Commitments and Contingencies E

Commitments and Contingencies Export compliance matter (Details) € in Millions, $ in Millions	3 Months Ended	9 Months Ended
	Apr. 03, 2021USD ($)	Jul. 03, 2021EUR (€)
Commitments and Contingencies Disclosure [Abstract]
Export compliance related transactions | €		€ 1.5
Discretionary Payment To Financial Advisors | $	$ 3

Earnings Per Share (Details)

Earnings Per Share (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jul. 03, 2021	Apr. 03, 2021	Jan. 02, 2021	Jul. 04, 2020	Apr. 04, 2020	Dec. 28, 2019	Jul. 03, 2021	Jul. 04, 2020
Earnings Per Share, Basic and Diluted [Abstract]
Weighted average shares outstanding—basic (in shares)	24,435,000			24,159,000			24,362,000	24,075,000
Dilutive effect of employee stock awards (in shares)	407,000			0			0	0
Weighted average shares outstanding—diluted (in shares)	24,842,000			24,159,000			24,362,000	24,075,000
Net income (loss)	$ 30,262	$ (158,215)	$ 144	$ (8,708)	$ (418,913)	$ 5,793	$ (127,809)	$ (421,828)
Dilutive securities excluded from calculation of dilutive shares	406,568

Other Income (Expense) (Details

Other Income (Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Component of Other Income (Expense), Nonoperating [Line Items]
Other—net	$ 1,185	$ (505)	$ 5,088	$ (1,322)
Foreign exchange loss
Component of Other Income (Expense), Nonoperating [Line Items]
Foreign exchange loss	(1,323)	(1,623)	(2,955)	(3,316)
Gain on deferred compensation investments, net
Component of Other Income (Expense), Nonoperating [Line Items]
Gain on deferred compensation investments, net	2,672	619	7,538	1,426
Other
Component of Other Income (Expense), Nonoperating [Line Items]
Other	$ (164)	$ 499	$ 505	$ 568

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	Mar. 25, 2021	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Business Acquisition [Line Items]
Effective income tax rate (percent)		22.10%	59.60%	12.00%	6.90%
Lumentum Holdings Inc.
Business Acquisition [Line Items]
Merger and acquisition costs	$ 217,600,000

Defined Benefit Plans (Details)

Defined Benefit Plans (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Postemployment Benefits [Abstract]
Net periodic pension (benefit) cost	$ 0.8	$ 0.6	$ 1.8	$ 1.4

Segment and Geographic Inform_3

Segment and Geographic Information - Sales and Income (Loss) from Operations (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Jul. 03, 2021USD ($)	Jul. 04, 2020USD ($)	Jul. 03, 2021USD ($)segments	Jul. 04, 2020USD ($)
Segment Reporting [Abstract]
Number of reporting segments | segments			2
Segment Reporting Information [Line Items]
Net sales	$ 395,759	$ 298,330	$ 1,095,794	$ 912,248
Total income (loss) from operations	42,104	(1,174)	(137,182)	(439,895)
Total other expense, net	(3,277)	(4,282)	(8,092)	(12,979)
Income (loss) before income taxes	38,827	(5,456)	(145,274)	(452,874)
OEM Laser Sources
Segment Reporting Information [Line Items]
Net sales	235,774	184,694	670,184	559,364
Income (loss) from operations:	54,310	42,853	155,353	126,030
Industrial Lasers & Systems
Segment Reporting Information [Line Items]
Net sales	159,985	113,636	425,610	352,884
Income (loss) from operations:	13,239	(20,571)	7,930	(512,716)
Corporate and other
Segment Reporting Information [Line Items]
Income (loss) from operations:	$ (25,445)	$ (23,456)	$ (300,465)	$ (53,209)

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. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020
Geographic information [Line Items]
Net sales	$ 395,759	$ 298,330	$ 1,095,794	$ 912,248
United States
Geographic information [Line Items]
Net sales	88,370	65,094	242,638	215,236
Total foreign countries sales
Geographic information [Line Items]
Net sales	307,389	233,236	853,156	697,012
South Korea
Geographic information [Line Items]
Net sales	67,883	63,428	202,274	180,412
China
Geographic information [Line Items]
Net sales	76,005	52,837	205,649	148,407
Japan
Geographic information [Line Items]
Net sales	28,900	22,272	92,394	70,990
Asia-Pacific, other
Geographic information [Line Items]
Net sales	38,589	24,090	97,320	67,889
Germany
Geographic information [Line Items]
Net sales	38,815	28,650	104,385	90,485
Europe, other
Geographic information [Line Items]
Net sales	36,624	27,917	99,692	95,130
Rest of World
Geographic information [Line Items]
Net sales	$ 20,573	$ 14,042	$ 51,442	$ 43,699

Segment and Geographic Inform_5

Segment and Geographic Information - Major Customers (Details) - Customer Concentration Risk	3 Months Ended		9 Months Ended		12 Months Ended
	Jul. 03, 2021	Jul. 04, 2020	Jul. 03, 2021	Jul. 04, 2020	Oct. 03, 2020
Sales | Customer 1
Concentration Risk [Line Items]
Concentration risk, percentage	13.90%	17.10%	15.50%	16.70%
Accounts receivable | Customer 3
Concentration Risk [Line Items]
Concentration risk, percentage			20.30%		24.20%

Restructuring Charges (Details)

Restructuring Charges (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Jul. 03, 2021	Apr. 03, 2021	Jan. 02, 2021	Jul. 04, 2020	Apr. 04, 2020	Dec. 28, 2019	Jul. 03, 2021	Jul. 04, 2020
Restructuring Reserve [Roll Forward]
Starting balance	$ 4,324	$ 3,879	$ 2,841	$ 4,257	$ 7,895	$ 8,494	$ 2,841	$ 8,494
Provision	160	3,658	5,383	518	1,079	933
Payments and other	(1,356)	(3,213)	(4,345)	(3,721)	(4,717)	(1,532)
Ending balance	3,128	4,324	3,879	1,054	4,257	7,895	3,128	1,054
Restructuring cost incurred						100
Restructuring charges relating to accelerated depreciation and consulting				100	500	600
Santa Clara facility combine project related restructuring charge		100		400	600	200
Industrial Lasers & Systems
Restructuring Reserve [Roll Forward]
Restructuring cost incurred	200			100			9,100	1,300
OEM Laser Sources
Restructuring Reserve [Roll Forward]
Restructuring cost incurred	0			400			100	1,200
Severance Related
Restructuring Reserve [Roll Forward]
Starting balance	3,618	2,875	2,611	4,045	7,675	8,279	2,611	8,279
Provision	(244)	2,775	819	(77)	85	54
Payments and other	(756)	(2,032)	(555)	(3,136)	(3,715)	(658)
Ending balance	2,618	3,618	2,875	832	4,045	7,675	2,618	832
Severance Related | Other current liabilities
Restructuring Reserve [Roll Forward]
Ending balance	3,100						3,100
Asset Write-Offs
Restructuring Reserve [Roll Forward]
Starting balance	0	0	0	0	0	0	0	0
Provision	318	558	3,509	554	915	599
Payments and other	(318)	(558)	(3,509)	(554)	(915)	(599)
Ending balance	0	0	0	0	0	0	0	0
Other
Restructuring Reserve [Roll Forward]
Starting balance	706	1,004	230	212	220	215	230	215
Provision	86	325	1,055	41	79	280
Payments and other	(282)	(623)	(281)	(31)	(87)	(275)
Ending balance	510	706	1,004	$ 222	$ 212	$ 220	$ 510	$ 222
Write-offs of Excess Inventory and Accruals for Vendor Commitments
Restructuring Reserve [Roll Forward]
Restructuring cost incurred	$ 200	$ 3,600	$ 5,400