IPG Photonics (IPGP) 10-Q 3 Nov 20 2020 Q3 Quarterly report Financial data

Cover Page

Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Nov. 02, 2020
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-33155
Entity Registrant Name	IPG PHOTONICS CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3444218
Entity Address, Address Line One	50 Old Webster Road
Entity Address, City or Town	Oxford
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01540
City Area Code	508
Local Phone Number	373-1100
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
Title of 12(b) Security	Common Stock, par value $0.0001 per share
Trading Symbol	IPGP
Security Exchange Name	NASDAQ
Entity Common Stock, Shares Outstanding (in shares)		53,300,660
Amendment Flag	false
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2020
Current Fiscal Year End Date	--12-31
Entity Central Index Key	0001111928

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents	$ 763,920	$ 680,070
Short-term investments	537,696	502,546
Accounts receivable, net	240,352	238,479
Inventories	370,344	380,790
Prepaid income taxes	60,436	38,873
Prepaid expenses and other current assets	58,905	55,876
Total current assets	2,031,653	1,896,634
Deferred income taxes, net	38,616	31,395
Goodwill	37,731	82,092
Intangible assets, net	64,999	74,271
Property, plant and equipment, net	576,398	600,852
Other assets	45,535	45,192
Total assets	2,794,932	2,730,436
Current liabilities:
Current portion of long-term debt	3,792	3,740
Accounts payable	37,375	27,329
Accrued expenses and other current liabilities	156,472	149,782
Income taxes payable	3,806	11,053
Total current liabilities	201,445	191,904
Deferred income taxes and other long-term liabilities	87,296	98,121
Long-term debt, net of current portion	35,117	37,968
Total liabilities	323,858	327,993
Commitments and contingencies (Note 12)
IPG Photonics Corporation equity:
Common stock, $0.0001 par value, 175,000,000 shares authorized; 55,278,428 and 53,244,416 shares issued and outstanding, respectively, at September 30, 2020; 54,743,227 and 53,010,875 shares issued and outstanding, respectively, at December 31, 2019.	6	5
Treasury stock, at cost, 2,034,012 and 1,732,352 shares held at September 30, 2020 and December 31, 2019, respectively.	(303,614)	(265,730)
Additional paid-in capital	828,796	785,636
Retained earnings	2,138,852	2,028,734
Accumulated other comprehensive loss	(193,827)	(146,919)
Total IPG Photonics Corporation equity	2,470,213	2,401,726
Non-controlling interests	861	717
Total equity	2,471,074	2,402,443
Total liabilities and equity	$ 2,794,932	$ 2,730,436

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2020	Dec. 31, 2019
Statement of Financial Position [Abstract]
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, shares authorized (in shares)	175,000,000	175,000,000
Common stock, shares issued (in shares)	55,278,428	54,743,227
Common stock, shares outstanding (in shares)	53,244,416	53,010,875
Treasury stock (in shares)	2,034,012	1,732,352

Condensed Consolidated Statemen

Condensed Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Net sales	$ 318,441	$ 329,138	$ 864,094	$ 1,007,954
Cost of sales	165,649	176,280	471,977	525,948
Gross profit	152,792	152,858	392,117	482,006
Operating expenses:
Sales and marketing	17,332	18,969	53,341	58,907
Research and development	31,710	32,160	95,132	99,528
General and administrative	29,038	26,776	82,561	82,526
Goodwill impairment	44,589	0	44,589	0
Impairment of long-lived assets and other restructuring charges	12	0	1,177	0
(Gain) loss on foreign exchange	(11,302)	808	(18,101)	7,495
Total operating expenses	111,379	78,713	258,699	248,456
Operating income	41,413	74,145	133,418	233,550
Other income, net:
Interest income, net	1,168	3,734	6,097	11,737
Other income (expense), net	(59)	(520)	581	129
Total other income	1,109	3,214	6,678	11,866
Income before provision for income taxes	42,522	77,359	140,096	245,416
Provision for income taxes	6,992	20,232	29,434	60,852
Net income	35,530	57,127	110,662	184,564
Less: net (loss) income attributable to non-controlling interests	(74)	(126)	429	(120)
Net income attributable to IPG Photonics Corporation	$ 35,604	$ 57,253	$ 110,233	$ 184,684
Net income attributable to IPG Photonics Corporation per share:
Basic (in dollars per share)	$ 0.67	$ 1.08	$ 2.07	$ 3.48
Diluted (in dollars per share)	$ 0.66	$ 1.07	$ 2.05	$ 3.43
Weighted average shares outstanding:
Basic (in shares)	53,098	52,928	53,136	53,073
Diluted (in shares)	53,664	53,622	53,691	53,864

Condensed Consolidated Statem_2

Condensed Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Statement of Comprehensive Income [Abstract]
Net income	$ 35,530	$ 57,127	$ 110,662	$ 184,564
Other comprehensive income, net of tax:
Translation adjustments	(8,562)	(30,371)	(46,445)	(11,413)
Adjustment for net gain realized and included in net income	(232)	0	(232)	0
Unrealized (loss) gain on derivatives	(551)	3	(516)	(2)
Total other comprehensive loss	(9,345)	(30,368)	(47,193)	(11,415)
Comprehensive income	26,185	26,759	63,469	173,149
Comprehensive (loss) income attributable to non-controlling interests	(93)	(165)	144	(138)
Comprehensive income attributable to IPG Photonics Corporation	$ 26,278	$ 26,924	$ 63,325	$ 173,287

Condensed Consolidated Statem_3

Condensed Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income	$ 110,662	$ 184,564
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	71,188	72,531
Deferred income taxes	(10,122)	(4,214)
Stock-based compensation	26,394	25,571
Goodwill impairment	44,589	0
Impairment of long-lived assets	671	0
Unrealized (gain) loss on foreign currency transactions	(21,759)	7,033
Other	6,823	854
Provisions for inventory, warranty and bad debt	42,559	38,748
Changes in assets and liabilities that provided (used) cash, net of acquisitions:
Accounts receivable	2,308	(7,562)
Inventories	(34,213)	(51,032)
Prepaid expenses and other assets	(2,065)	11,087
Accounts payable	8,819	(8,137)
Accrued expenses and other liabilities	(17,492)	(26,113)
Income and other taxes payable	(28,345)	(49,748)
Net cash provided by operating activities	200,017	193,582
Cash flows from investing activities:
Purchases of and deposits on property, plant and equipment	(61,871)	(107,540)
Proceeds from sales of property, plant and equipment	689	348
Purchases of short-term and long-term investments	(732,729)	(557,674)
Proceeds from short-term investments	697,816	568,501
Acquisitions of businesses, net of cash acquired	0	(15,115)
Other	17	243
Net cash used in investing activities	(96,078)	(111,237)
Cash flows from financing activities:
Proceeds from line-of-credit facilities	0	15
Payments on line-of-credit facilities	0	(15)
Principal payments on long-term borrowings	(2,798)	(2,747)
Proceeds from issuance of common stock under employee stock option and purchase plans less payments for taxes related to net share settlement of equity awards	16,767	1,644
Purchase of treasury stock, at cost	(37,884)	(25,921)
Payment of purchase price holdback from business combination	(1,650)	0
Net cash used in financing activities	(25,565)	(27,024)
Effect of changes in exchange rates on cash, cash equivalents and restricted cash	4,692	(16,561)
Net increase in cash, cash equivalents and restricted cash	83,066	38,760
Cash, cash equivalents and restricted cash — Beginning of period	682,984	544,358
Cash, cash equivalents and restricted cash — End of period	766,050	583,118
Supplemental disclosure of cash flow information:
Cash paid for interest	1,650	1,655
Cash paid for income taxes	65,895	97,172
Non-cash transactions:
Demonstration units transferred from inventory to other assets	6,724	8,892
Inventory transferred to machinery and equipment	2,362	8,250
Changes in accounts payable related to property, plant and equipment	1,248	2,721
Leased assets obtained in exchange for new operating lease liabilities	$ 2,764	$ 11,944

Condensed Consolidated Statem_4

Condensed Consolidated Statements Of Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Retained EarningsCumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive (Loss) Income	Non- controlling Interest
Balance, beginning of year (in shares) at Dec. 31, 2018			52,941,607	1,430,094
Balance, beginning of period at Dec. 31, 2018	$ 2,206,235		$ 5	$ (224,998)	$ 744,937	$ 1,848,500		$ (162,896)	$ 687
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of RSU's and PSU's (in shares)			259,749
Exercise of stock options and vesting of RSU's and PSU's	(2,321)				(2,321)
Common stock issued under employee stock purchase plan (in shares)			31,483
Common stock issued under employee stock purchase plan	3,965				3,965
Purchased common stock (in shares)			(196,996)	(196,996)
Purchased common stock	(25,921)			$ (25,921)
Stock-based compensation	25,571				25,571
Net income	184,564					184,684			(120)
Foreign currency translation adjustments	(11,431)							(11,413)	(18)
Unrealized (loss) gain on derivatives	(2)							(2)
Balance, end of period (in shares) at Sep. 30, 2019			53,035,843	1,627,090
Balance, end of period at Sep. 30, 2019	2,380,660		$ 5	$ (250,919)	772,152	2,033,184		(174,311)	549
Balance, beginning of year (in shares) at Jun. 30, 2019			53,182,910	1,446,470
Balance, beginning of period at Jun. 30, 2019	2,367,361		$ 5	$ (227,282)	761,936	1,975,931		(143,943)	714
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of RSU's and PSU's (in shares)			33,553
Exercise of stock options and vesting of RSU's and PSU's	1,676				1,676
Purchased common stock (in shares)			(180,620)	(180,620)
Purchased common stock	(23,637)			$ (23,637)
Stock-based compensation	8,540				8,540
Net income	57,127					57,253			(126)
Foreign currency translation adjustments	(30,410)							(30,371)	(39)
Unrealized (loss) gain on derivatives	3							3
Balance, end of period (in shares) at Sep. 30, 2019			53,035,843	1,627,090
Balance, end of period at Sep. 30, 2019	2,380,660		$ 5	$ (250,919)	772,152	2,033,184		(174,311)	549
Balance, beginning of year (in shares) at Dec. 31, 2019			53,010,875	1,732,352
Balance, beginning of period at Dec. 31, 2019	2,402,443	$ (115)	$ 5	$ (265,730)	785,636	2,028,734	$ (115)	(146,919)	717
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of RSU's and PSU's (in shares)			514,717
Exercise of stock options and vesting of RSU's and PSU's	14,217		$ 1		14,216
Common stock issued under employee stock purchase plan (in shares)			20,484
Common stock issued under employee stock purchase plan	2,550				2,550
Purchased common stock (in shares)			(301,660)	(301,660)
Purchased common stock	(37,884)			$ (37,884)
Stock-based compensation	26,394				26,394
Net income	110,662					110,233			429
Foreign currency translation adjustments	(46,445)							(46,160)	(285)
Unrealized (loss) gain on derivatives	(516)							(516)
Adjustment for net gain realized and included in net income	(232)							(232)
Balance, end of period (in shares) at Sep. 30, 2020			53,244,416	2,034,012
Balance, end of period at Sep. 30, 2020	2,471,074		$ 6	$ (303,614)	828,796	2,138,852		(193,827)	861
Balance, beginning of year (in shares) at Jun. 30, 2020			53,182,148	1,972,540
Balance, beginning of period at Jun. 30, 2020	2,437,306		$ 6	$ (293,960)	811,559	2,103,248		(184,501)	954
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of RSU's and PSU's (in shares)			123,740
Exercise of stock options and vesting of RSU's and PSU's	8,497				8,497
Purchased common stock (in shares)			(61,472)	(61,472)
Purchased common stock	(9,654)			$ (9,654)
Stock-based compensation	8,740				8,740
Net income	35,530					35,604			(74)
Foreign currency translation adjustments	(8,562)							(8,543)	(19)
Unrealized (loss) gain on derivatives	(551)							(551)
Adjustment for net gain realized and included in net income	(232)							(232)
Balance, end of period (in shares) at Sep. 30, 2020			53,244,416	2,034,012
Balance, end of period at Sep. 30, 2020	$ 2,471,074		$ 6	$ (303,614)	$ 828,796	$ 2,138,852		$ (193,827)	$ 861

Basis Of Presentation And Signi

Basis Of Presentation And Significant Accounting Policies	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation and Significant Accounting Policies	BASIS OF PRESENTATION AND SIGNIFICANT ACCOUNTING POLICIES Basis of Presentation — The accompanying unaudited condensed consolidated financial statements have been prepared by IPG Photonics Corporation, or "IPG", "its" or the "Company". Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). The condensed consolidated financial statements include the Company's accounts and those of its subsidiaries. All intercompany balances have been eliminated in consolidation. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto in the Company's Annual Report on Form 10-K for the year ended December 31, 2019. In the opinion of the Company's management, the financial information for the interim periods presented reflects all adjustments necessary for a fair presentation of the Company's financial position, results of operations and cash flows. The results reported in these condensed consolidated financial statements are not necessarily indicative of results that may be expected for the entire year. Accounts Receivable and Allowance for Doubtful Accounts — The Company maintains an allowance for doubtful accounts to provide for the estimated amount of accounts receivable that will not be collected. The allowance is based upon an estimate of expected credit losses over the life of outstanding receivables. The estimate involves an assessment of customer creditworthiness, historical payment experience, an assumption of future expected credit losses, and the age of outstanding receivables. Activity related to the allowance for doubtful accounts was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Balance, beginning of period $ 1,999 $ 2,528 $ 2,547 $ 1,799 Provision for bad debts, net of recoveries 143 (27) (206) 767 Uncollectable accounts written off (1) (3) (72) (91) Foreign currency translation (80) (56) (208) (33) Balance, end of period $ 2,061 $ 2,442 $ 2,061 $ 2,442

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS Adopted Pronouncements — In June 2016, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"), which adds an impairment model (known as the current expected credit loss ("CECL") model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance for its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce the complexity by decreasing the number of credit impairment models that entities use to account for debt instruments. The Company adopted ASU 2016-03, along with its subsequent clarifications, as of January 1, 2020. The cumulative effect of the changes made to the Company's condensed consolidated January 1, 2020 balance sheet for the adoption of ASU 2016-13 was as follows: Balance at Adoption of Balance at December 31, 2019 ASU 2016-13 January 1, 2020 Balance Sheet Accounts receivable, net $ 238,479 $ (148) $ 238,331 Deferred income taxes, net 31,395 33 31,428 Retained earnings 2,028,734 (115) 2,028,619

Revenue From Contracts With Cus

Revenue From Contracts With Customers	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue From Contracts With Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS Sales are derived from products for different applications: fiber lasers, diode lasers, diodes and systems for materials processing, fiber lasers and amplifiers for advanced applications, fiber amplifiers and transceivers for communications applications, and fiber lasers for medical applications. The following tables represent a disaggregation of revenue from contracts with customers: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Sales by Application Materials processing $ 290,028 $ 306,260 $ 779,810 $ 952,936 Other applications 28,413 22,878 84,284 55,018 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 Sales by Product High Power Continuous Wave ("CW") Lasers $ 184,387 $ 184,924 $ 461,181 $ 577,354 Medium Power CW Lasers 11,756 11,891 33,701 42,904 Pulsed Lasers 34,975 33,850 109,391 106,100 Quasi-Continuous Wave ("QCW") Lasers 15,079 12,479 38,660 42,612 Laser and Non-Laser Systems 20,841 32,929 64,417 104,943 Other Revenue including Amplifiers, Service, Parts, Accessories and Change in Deferred Revenue 51,403 53,065 156,744 134,041 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 Sales by Geography North America $ 52,732 $ 71,000 $ 173,972 $ 199,947 Europe: Germany 16,163 17,204 51,208 59,487 Other including Eastern Europe/CIS 54,907 62,196 158,686 192,527 Asia and Australia: China 148,049 121,290 361,864 399,246 Japan 12,884 21,859 41,241 54,879 Other 31,227 28,877 70,924 89,544 Rest of World 2,479 6,712 6,199 12,324 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 Timing of Revenue Recognition Goods and services transferred at a point in time $ 308,474 $ 310,324 $ 824,069 $ 944,454 Goods and services transferred over time 9,967 18,814 40,025 63,500 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 One of the Company's customers accounted for 35% and 24% of the Company's net accounts receivable as of September 30, 2020 and December 31, 2019, respectively. The Company enters into contracts to sell lasers and spare parts, for which revenue is generally recognized upon shipment or delivery, depending on the terms of the contract. The Company also provides installation services and extended warranties. The Company frequently receives consideration from a customer prior to transferring goods to the customer under the terms of a sales contract. The Company records customer deposits related to these prepayments, which represent a contract liability. The Company also records deferred revenue related to installation services when consideration is received before the services have been performed. The Company recognizes customer deposits and deferred revenue as net sales after control of the goods or services has been transferred to the customer and all revenue recognition criteria are met. The Company bills customers for extended warranties upon entering into the agreement with the customer, resulting in deferred revenue. The timing of customer payments on contracts for the sale of customized robotic systems generally differs from the timing of revenue recognized, resulting in contract assets and liabilities. Contract assets are included within prepaid expense and other current assets on the condensed consolidated balance sheets. Contract liabilities are included within accrued expenses and other current liabilities on the condensed consolidated balance sheets. The following table reflects the changes in the Company's contract assets and liabilities for the nine months ended September 30, 2020 and 2019: September 30, December 31, September 30, December 31, 2020 2019 Change 2019 2018 Change Contract assets Contract assets $ 6,771 $ 9,645 $ (2,874) $ 10,606 $ 10,102 $ 504 Contract liabilities Contract liabilities - current 57,034 59,531 (2,497) 49,358 52,606 (3,248) Contract liabilities - long-term 2,121 1,820 301 1,677 1,413 264 During the three months ended September 30, 2020 and 2019 the Company recognized revenue of $10,179 and $4,534, respectively, that was included in contract liabilities at the beginning of each period. During the nine months ended September 30, 2020 and 2019, the Company recognized revenue of $41,622 and $40,786, respectively, that was included in contract liabilities at the beginning of each period. The Company has elected the practical expedient in ASC 606-10-50-14, whereby the performance obligations for contracts with an original expected duration of one year or less are not disclosed. The following table represents the Company's remaining performance obligations from contracts that are recognized over time as of September 30, 2020: Remaining Performance Obligations 2020 (a) 2021 2022 2023 2024 Thereafter Total Revenue expected to be recognized for extended warranty agreements $ 1,439 $ 2,724 $ 874 $ 566 $ 265 $ 56 $ 5,924 Revenue to be earned over time from contracts to sell robotic systems 10,934 16,941 — — — — 27,875 Total $ 12,373 $ 19,665 $ 874 $ 566 $ 265 $ 56 $ 33,799 (a) For the three-month period beginning October 1, 2020.

Restricted Cash

Restricted Cash	9 Months Ended
	Sep. 30, 2020
Cash and Cash Equivalents [Abstract]
Restricted Cash	RESTRICTED CASH The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets to the total of the same amounts shown in the condensed consolidated statements of cash flows. September 30, December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 763,920 $ 580,329 $ 680,070 $ 544,358 Restricted cash included in prepaid expenses and other current assets 2,130 — — — Restricted cash included in other assets — 2,789 2,914 — Cash, cash equivalents and restricted cash in the condensed consolidated statements of cash flows $ 766,050 $ 583,118 $ 682,984 $ 544,358

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTSThe Company's financial instruments consist of cash equivalents, short-term and long-term investments, accounts receivable, auction rate securities, accounts payable, drawings on revolving lines of credit, long-term debt, interest rate swaps and contingent purchase consideration. The valuation techniques used to measure fair value are based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect internal market assumptions. These two types of inputs create the following fair value hierarchy: Level 1, defined as observable inputs such as quoted prices for identical instruments in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The Company classifies its financial instruments according to the prescribed criteria. The following table presents fair value information related to the Company's assets and liabilities measured at amortized cost on the condensed consolidated balance sheets with the exception of the interest rate swap, which is measured at fair value: Fair Value Measurements at September 30, 2020 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 269,955 $ 269,955 $ — $ — Commercial paper 126,563 — 126,563 — Corporate bonds 25,142 — 25,142 — U.S. Treasury and agency obligations 11,799 — 11,799 — Short-term investments: Corporate bonds 183,827 — 183,827 — Commercial paper 316,167 — 316,167 — U.S. Treasury and agency obligations 38,144 — 38,144 — Total $ 971,597 $ 269,955 $ 701,642 $ — Liabilities Long-term debt $ 39,436 $ — $ 39,436 $ — Interest rate swap 666 — 666 — Total $ 40,102 $ — $ 40,102 $ — Fair Value Measurements at December 31, 2019 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 155,080 $ 155,080 $ — $ — Commercial paper 54,712 — 54,712 — Short-term investments: Corporate bonds 259,422 259,422 — — Commercial paper 236,752 — 236,752 — Certificate of deposit 6,501 6,501 — — Long-term investments and other assets: Auction rate securities 592 — — 592 Interest rate swaps 13 — 13 — Total $ 713,072 $ 421,003 $ 291,477 $ 592 Liabilities Long-term debt $ 42,004 $ — $ 42,004 $ — Contingent purchase consideration 273 — — 273 Total $ 42,277 $ — $ 42,004 $ 273 The carrying amounts of money market fund deposits, term deposits, accounts receivable, accounts payable and drawings on revolving lines of credit are considered reasonable estimates of their fair market value due to the short maturity of most of these instruments or as a result of the competitive market interest rates which have been negotiated. The fair value of the short-term investments considered held-to-maturity as of September 30, 2020 and December 31, 2019 was $538,138 and $502,675, respectively, which include an unrealized gain of $442 and $129, respectively, as compared to the book value recorded on the condensed consolidated balance sheets for the same periods. There were no impairments for the investments considered held-to-maturity during the quarters ended September 30, 2020 and 2019. There were no current expected credit loss allowances for the investments considered held-to-maturity at September 30, 2020. The Company holds highly-rated held-to-maturity instruments that are within one year of maturity. The auction rate securities were called during the quarter ended September 30, 2020. The net gain previously included in accumulated other comprehensive income was released and included in net income, in the amount of $232. The fair value of the auction rate securities at December 31, 2019 were measured using prices observed in inactive markets with limited observable data for the securities held by the Company. They were considered available-for-sale securities and had a cost basis of $592 at December 31, 2019. There were no impairments for the investments considered available-for-sale during the quarters ended September 30, 2020 and 2019. The Company entered into an interest rate swap that is designated as a cash flow hedge associated with a long-term note issued during the second quarter of 2016 that will terminate with the long-term note in May 2023. The fair value at September 30, 2020 for the interest rate swap considered pricing models whose inputs are observable for the securities held by the Company. At September 30, 2020 and December 31, 2019, the Company's long-term notes consisted of a variable rate note and a fixed rate note, and are reported at amortized cost on the condensed consolidated balance sheets. For disclosure purposes, the fair value of the long-term notes was estimated using a discounted cash flow model using observable market interest rates and are classified as a level 2. Based on the discounted cash flow model, the fair value of the long-term notes at September 30, 2020 was $39,436 as compared to the book value of $38,909. At December 31, 2019, the book value approximated fair value. The fair value of contingent consideration at December 31, 2019 was determined using an income approach at the respective business combination date and at the reporting date. That approach is based on significant inputs that are not observable in the market and include key assumptions such as assessing the probability of meeting certain milestones required to earn the contingent consideration. The following table presents information about the Company's movement in Level 3 assets and liabilities measured at fair value: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Auction rate securities Balance, beginning of period $ 596 $ 852 $ 592 $ 847 Redemptions (596) (264) (596) (264) Change in fair value and accretion — 2 4 7 Balance, end of period $ — $ 590 $ — $ 590 Contingent purchase consideration Balance, beginning of period $ — $ 300 $ 273 $ 898 Cash payments — — (272) (632) Foreign exchange adjustment — (3) (1) 31 Balance, end of period $ — $ 297 $ — $ 297 The following table presents the effective maturity dates of held-to-maturity and available-for-sale debt investments as of September 30, 2020 and December 31, 2019: September 30, 2020 December 31, 2019 Book Value Fair Value Book Value Fair Value Investment maturity Held-to-maturity: Less than 1 year $ 537,696 $ 538,138 $ 502,546 $ 502,675 Available-for-sale: Greater than 5 years $ — $ — $ 592 $ 592

Inventories

Inventories	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following: September 30, December 31, 2020 2019 Components and raw materials $ 193,765 $ 200,390 Work-in-process 46,714 49,620 Finished components and devices 129,865 130,780 Total $ 370,344 $ 380,790 The Company recorded inventory provisions totaling $11,514 and $7,303 for the three months ended September 30, 2020 and 2019, respectively, and $25,955 and $19,952 for the nine months ended September 30, 2020 and 2019, respectively. These provisions relate to the recoverability of the value of inventories due to technological changes and excess quantities. These provisions are reported as a reduction to components and raw materials and finished components and devices.

Goodwill And Intangibles

Goodwill And Intangibles	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	GOODWILL AND INTANGIBLES The following table sets forth the changes in the carrying amount of goodwill: Nine Months Ended September 30, 2020 2019 Balance at January 1 $ 82,092 $ 100,722 Goodwill arising from business combinations — 9,426 Adjustment to goodwill during measurement period — 448 Foreign exchange adjustment 228 (642) Impairment losses (44,589) — Balance at September 30 $ 37,731 $ 109,954 During the fourth quarter of 2018, the Company acquired 100% of the membership units of Genesis Systems Group, LLC ("Genesis"). During the first quarter of 2019, the working capital adjustment to the purchase price was finalized resulting in an increase in the purchase price of $448. The additional purchase price was allocated entirely to goodwill. At the time the acquisition was completed, the Company concluded that Genesis was a separate reporting unit. During the third quarter of 2020, the Company concluded that declines in revenue and order flow for the Genesis custom systems business caused by pandemic-related decreases in capital spending in the aerospace and transportation industries were a triggering event requiring a goodwill impairment evaluation. The Company performed a quantitative assessment using the discounted cash flow method under the income approach as well as the guideline public company analysis and guideline transaction analysis under the market approach to estimate the fair value of the custom systems business. As a result, the Company recognized a non-cash impairment loss of $44,589, which was equal to the carrying amount of goodwill prior to its impairment. The analysis considered internal forecasts of sales, profitability and capital expenditures, as well as valuation multiples of comparable public companies and valuation multiples of transactions of comparable companies. Intangible assets, subject to amortization, consisted of the following: September 30, 2020 December 31, 2019 Gross Accumulated Net Carrying Weighted- Average Lives Gross Carrying Accumulated Net Carrying Weighted- Customer relationships $ 57,897 $ (16,184) $ 41,713 11 years $ 57,866 $ (11,993) $ 45,873 11 years Technology, trademark and trade name 40,414 (19,527) 20,887 7 years 41,297 (16,128) 25,169 7 years Production know-how 9,250 (7,983) 1,267 7 years 9,180 (7,415) 1,765 7 years Patents 8,036 (6,904) 1,132 8 years 8,036 (6,572) 1,464 8 years Total $ 115,597 $ (50,598) $ 64,999 $ 116,379 $ (42,108) $ 74,271 Amortization expense for the three months ended September 30, 2020 and 2019 was $2,947 and $3,617, respectively. Amortization expense for the nine months ended September 30, 2020 and 2019 was $9,029 and $10,581, respectively. The estimated future amortization expense for intangibles for the remainder of 2020 and subsequent years is as follows: 2020 (a) 2021 2022 2023 2024 Thereafter Total $ 2,939 $ 11,574 10,746 $ 9,858 $ 7,510 $ 22,372 $ 64,999 (a) For the three-month period beginning October 1, 2020.

Accrued Expenses And Other Liab

Accrued Expenses And Other Liabilities	9 Months Ended
	Sep. 30, 2020
Payables and Accruals [Abstract]
Accrued Expenses And Other Liabilities	ACCRUED EXPENSES AND OTHER LIABILITIES Accrued expenses and other liabilities consist of the following: September 30, December 31, 2020 2019 Accrued compensation $ 57,265 $ 48,881 Contract liabilities 57,034 59,531 Current portion of accrued warranty 23,971 23,114 Short-term lease liabilities 5,573 5,300 Other 12,629 12,956 Total $ 156,472 $ 149,782

Product Warranties

Product Warranties	9 Months Ended
	Sep. 30, 2020
Product Warranties Disclosures [Abstract]
Product Warranties	PRODUCT WARRANTIES The Company typically provides one The following table summarizes product warranty accrual activity recorded during the nine months ended September 30, 2020 and 2019. 2020 2019 Balance at January 1 $ 48,866 $ 51,422 Provision for warranty accrual 16,255 16,916 Warranty claims (20,992) (17,399) Foreign currency translation 822 (1,077) Balance at September 30 $ 44,951 $ 49,862 Accrued warranty reported in the accompanying condensed consolidated financial statements as of September 30, 2020 and December 31, 2019 consisted of $23,971 and $23,114 in accrued expenses and other liabilities, respectively, and $20,980 and $25,752 in other long-term liabilities, respectively.

Financing Arrangements

Financing Arrangements	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Financing Arrangements	FINANCING ARRANGEMENTS The Company's borrowings under existing financing arrangements consist of the following: September 30, December 31, 2020 2019 Total notes payable $ 38,909 $ 41,708 Less: current portion (3,792) (3,740) Total long-term debt $ 35,117 $ 37,968 Term Debt: At September 30, 2020, the Company has an unsecured long-term note with an outstanding principal balance of $18,703, of which, $1,188 is the current portion. The interest on this unsecured long-term note is variable at 1.20% above LIBOR and is fixed using an interest rate swap at 2.85% per annum. The unsecured long-term note matures in May 2023, at which time the outstanding principal balance will be $15,438. Also at September 30, 2020, the Company has another long-term note that is secured by its corporate aircraft with an outstanding principal balance of $20,206, of which, $2,604 is the current portion. The interest on this collateralized long-term note is fixed at 2.74% per annum. The collateralized long-term note matures in July 2022, at which time the outstanding principal balance will be $15,375. The future principal payments for the Company’s Notes as of September 30, 2020 are as follows: 2020 (a) $ 942 2021 3,810 2022 18,126 2023 16,031 Total $ 38,909 (a) For the three-month period beginning October 1, 2020. Revolving Line of Credit Facilities:

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	DERIVATIVE FINANCIAL INSTRUMENTS The Company's only outstanding derivative financial instrument is an interest rate swap that is classified as a cash flow hedge of its variable rate debt. The fair value amounts in the condensed consolidated balance sheets were: September 30, December 31, 2020 2019 Notional amounts (1) $ 18,703 $ 19,594 Fair values: Other assets — 13 Deferred income taxes and other long-term liabilities 666 — (1) Notional amounts represent the gross contract/notional amount of the derivatives outstanding. The derivative gains and losses in the condensed consolidated financial statements for the three and nine months ended September 30, 2020 and 2019, related to the Company's current and previous interest rate swap contracts were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Effective portion recognized in other comprehensive income, pretax: Interest rate swap $ (723) $ 4 $ (679) $ 1

Commitments And Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2020
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIESFrom time to time, the Company may be involved in disputes and legal proceedings in the ordinary course of its business. These proceedings may include allegations of infringement of intellectual property, commercial disputes and employment matters. As of September 30, 2020 and through the filing date of these condensed consolidated financial statements, the Company has no legal proceedings ongoing that management estimates could have a material effect on the Company's condensed consolidated financial statements.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The effective tax rates were 16.4% and 26.2% for the three months ended September 30, 2020 and 2019, respectively, and 21.0% and 24.8% for the nine months ended September 30, 2020 and 2019, respectively. There were net discrete tax benefits of $727 and $5,443 for the three months ended September 30, 2020 and 2019, respectively, and $6,658 and $8,357 for the nine months ended September 30, 2020 and 2019, respectively. The reduction in the annual effective rate for the nine months ended September 30, 2020 compared with the nine months ended September 30, 2019 was primarily attributable to a greater share of income earned in lower tax rate jurisdictions, the new regulations for the Global Intangible Low-Taxed Income (“GILTI”) provisions of US tax law, which allowed companies to elect out for high taxed foreign income, and the benefit provided by tax credits and discrete items applied to the tax on significantly lower income in 2020. The change to GILTI provisions occurred during the three months ended September 30, 2020. Additionally, the mix of income earned in lower tax jurisdictions also increased during the three months ended September 30, 2020. Together, these reduced the year to date effective tax rate as compared to previous calculations. Income tax expense for the three months ended September 30, 2020 reflects the impact of these adjustments on income earned in the first two quarters, which resulted in a lower tax rate for the quarter. Discrete benefits for the three months ended September 30, 2020 included $1,896 related to the tax deductions for equity-based compensation that exceeded compensation expense recognized and $1,586 for provision to return adjustments which were offset by a detriment of $2,641 related to losses for which no tax benefit was recognized. Discrete benefits for the three months ended September 30, 2019 included $229 related to the tax deductions for equity-based compensation that exceeded compensation expense recognized and $5,326 for provision to return adjustments. For the nine months ended September 30, 2020, discrete benefits include $6,590 related to the tax deductions for equity-based compensation that exceeded compensation expense recognized and $3,867 for provision to return adjustments and an investment credit requested on an amended return, which were partially offset by $3,282 related to the tax effect of losses in subsidiaries for which no tax benefit was recognized. For the nine months ended September 30, 2019, discrete benefits include $4,271 related to the tax deductions for equity-based compensation that exceeded compensation expense recognized and $5,293 for provision to return adjustments. The Company accounts for its uncertain tax positions in accordance with the accounting standards for income taxes. The Company continues to classify interest and penalties related to unrecognized tax benefits as a component of the provision for income taxes. The following is a summary of the activity of the Company’s unrecognized tax benefits for nine months ended September 30, 2020 and 2019: 2020 2019 Balance at January 1, $ 11,416 $ 11,206 Additions for tax positions in current period 2,000 3,342 Foreign currency translation (938) (84) Balance at September 30, $ 12,478 $ 14,464

Net Income Attributable To IPG

Net Income Attributable To IPG Photonics Corporation Per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Net Income Attributable To IPG Photonics Corporation Per Share	NET INCOME ATTRIBUTABLE TO IPG PHOTONICS CORPORATION PER SHARE The following table sets forth the computation of diluted net income attributable to IPG Photonics Corporation per share: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net income attributable to IPG Photonics Corporation $ 35,604 $ 57,253 $ 110,233 $ 184,684 Net income attributable to common stockholders 35,604 57,253 110,233 184,684 Weighted average shares 53,098 52,928 53,136 53,073 Dilutive effect of common stock equivalents 566 694 555 791 Diluted weighted average common shares 53,664 53,622 53,691 53,864 Basic net income attributable to IPG Photonics Corporation per share $ 0.67 $ 1.08 $ 2.07 $ 3.48 Basic net income attributable to common stockholders $ 0.67 $ 1.08 $ 2.07 $ 3.48 Diluted net income attributable to IPG Photonics Corporation per share $ 0.66 $ 1.07 $ 2.05 $ 3.43 Diluted net income attributable to common stockholders $ 0.66 $ 1.07 $ 2.05 $ 3.43 The computation of diluted weighted average common shares excludes common stock equivalents including non-qualified stock options, performance stock units ("PSU's"), restricted stock units ("RSU's") and employee stock purchase plan ("ESPP") because the effect of including them would be anti-dilutive. The weighted average anti-dilutive shares outstanding for the three and nine months ended September 30, 2020 and 2019 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Non-qualified stock options 528,300 763,000 555,800 578,000 Restricted stock units 28,900 167,200 36,200 149,200 Performance stock units — 45,500 19,800 40,800 Employee stock purchase plan 5,500 6,100 16,400 18,200 Total weighed average anti-dilutive shares outstanding 562,700 981,800 628,200 786,200 On May 5, 2020, the Company announced that its Board of Directors authorized the purchase of up to $200,000 of IPG common stock. This new authorization is additive to the Company's existing stock repurchase of $125,000 repurchase program authorized in February 2019. Under the two share purchase authorizations, IPG may repurchase shares of common stock (a) in an amount not to exceed the lesser of the number of shares issued to employees and directors under the Company's various employee and director equity compensation and employee stock purchase plans in 2019 and 2020 or $125,000 and (b) $200,000, in both cases exclusive of any fees, commissions or other expenses. Share repurchases may be made periodically in open-market transactions using the Company's working capital and are subject to market conditions, legal requirements and other factors. The share purchase program authorization does not obligate the Company to repurchase any dollar amount or number of its shares, and repurchases may be commenced or suspended from time to time without prior notice.

Subsequent Events

Subsequent Events	9 Months Ended
	Sep. 30, 2020
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTSThe Company has evaluated subsequent events through the time of filing this Quarterly Report on Form 10-Q with the SEC. On October 1, 2020, the Company acquired Pi-Tecnologia S.A. ("PiTec"), which is located in Brazil, to support development in advanced photonics. The acquisition price was $2,717, of which $906 was paid at closing and the remainder of which may be earned over three years based on reaching certain financial targets.

Basis Of Presentation And Sig_2

Basis Of Presentation And Significant Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation — The accompanying unaudited condensed consolidated financial statements have been prepared by IPG Photonics Corporation, or "IPG", "its" or the "Company". Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). The condensed consolidated financial statements include the Company's accounts and those of its subsidiaries. All intercompany balances have been eliminated in consolidation. These condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto in the Company's Annual Report on Form 10-K for the year ended December 31, 2019.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts — The Company maintains an allowance for doubtful accounts to provide for the estimated amount of accounts receivable that will not be collected. The allowance is based upon an estimate of expected credit losses over the life of outstanding receivables. The estimate involves an assessment of customer creditworthiness, historical payment experience, an assumption of future expected credit losses, and the age of outstanding receivables.
Adopted Pronouncements	Adopted Pronouncements —

Accounting Policies (Policies)

Accounting Policies (Policies)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Adopted Pronouncements	Adopted Pronouncements —

Basis Of Presentation And Sig_3

Basis Of Presentation And Significant Accounting Policies (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Allowance for Doubtful Accounts	Activity related to the allowance for doubtful accounts was as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Balance, beginning of period $ 1,999 $ 2,528 $ 2,547 $ 1,799 Provision for bad debts, net of recoveries 143 (27) (206) 767 Uncollectable accounts written off (1) (3) (72) (91) Foreign currency translation (80) (56) (208) (33) Balance, end of period $ 2,061 $ 2,442 $ 2,061 $ 2,442

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Tables)	9 Months Ended
	Sep. 30, 2020
Accounting Policies [Abstract]
Cumulative Effect of Change to Balance Sheet	The cumulative effect of the changes made to the Company's condensed consolidated January 1, 2020 balance sheet for the adoption of ASU 2016-13 was as follows: Balance at Adoption of Balance at December 31, 2019 ASU 2016-13 January 1, 2020 Balance Sheet Accounts receivable, net $ 238,479 $ (148) $ 238,331 Deferred income taxes, net 31,395 33 31,428 Retained earnings 2,028,734 (115) 2,028,619

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables represent a disaggregation of revenue from contracts with customers: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Sales by Application Materials processing $ 290,028 $ 306,260 $ 779,810 $ 952,936 Other applications 28,413 22,878 84,284 55,018 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 Sales by Product High Power Continuous Wave ("CW") Lasers $ 184,387 $ 184,924 $ 461,181 $ 577,354 Medium Power CW Lasers 11,756 11,891 33,701 42,904 Pulsed Lasers 34,975 33,850 109,391 106,100 Quasi-Continuous Wave ("QCW") Lasers 15,079 12,479 38,660 42,612 Laser and Non-Laser Systems 20,841 32,929 64,417 104,943 Other Revenue including Amplifiers, Service, Parts, Accessories and Change in Deferred Revenue 51,403 53,065 156,744 134,041 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 Sales by Geography North America $ 52,732 $ 71,000 $ 173,972 $ 199,947 Europe: Germany 16,163 17,204 51,208 59,487 Other including Eastern Europe/CIS 54,907 62,196 158,686 192,527 Asia and Australia: China 148,049 121,290 361,864 399,246 Japan 12,884 21,859 41,241 54,879 Other 31,227 28,877 70,924 89,544 Rest of World 2,479 6,712 6,199 12,324 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954 Timing of Revenue Recognition Goods and services transferred at a point in time $ 308,474 $ 310,324 $ 824,069 $ 944,454 Goods and services transferred over time 9,967 18,814 40,025 63,500 Total $ 318,441 $ 329,138 $ 864,094 $ 1,007,954
Changes in Contract Assets and Liabilities	The following table reflects the changes in the Company's contract assets and liabilities for the nine months ended September 30, 2020 and 2019: September 30, December 31, September 30, December 31, 2020 2019 Change 2019 2018 Change Contract assets Contract assets $ 6,771 $ 9,645 $ (2,874) $ 10,606 $ 10,102 $ 504 Contract liabilities Contract liabilities - current 57,034 59,531 (2,497) 49,358 52,606 (3,248) Contract liabilities - long-term 2,121 1,820 301 1,677 1,413 264
Schedule of Remaining Performance Obligations	The following table represents the Company's remaining performance obligations from contracts that are recognized over time as of September 30, 2020: Remaining Performance Obligations 2020 (a) 2021 2022 2023 2024 Thereafter Total Revenue expected to be recognized for extended warranty agreements $ 1,439 $ 2,724 $ 874 $ 566 $ 265 $ 56 $ 5,924 Revenue to be earned over time from contracts to sell robotic systems 10,934 16,941 — — — — 27,875 Total $ 12,373 $ 19,665 $ 874 $ 566 $ 265 $ 56 $ 33,799 (a) For the three-month period beginning October 1, 2020.

Restricted Cash (Tables)

Restricted Cash (Tables)	9 Months Ended
	Sep. 30, 2020
Cash and Cash Equivalents [Abstract]
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets to the total of the same amounts shown in the condensed consolidated statements of cash flows. September 30, December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 763,920 $ 580,329 $ 680,070 $ 544,358 Restricted cash included in prepaid expenses and other current assets 2,130 — — — Restricted cash included in other assets — 2,789 2,914 — Cash, cash equivalents and restricted cash in the condensed consolidated statements of cash flows $ 766,050 $ 583,118 $ 682,984 $ 544,358
Schedule of Restricted Cash	The following table provides a reconciliation of cash, cash equivalents and restricted cash reported within the condensed consolidated balance sheets to the total of the same amounts shown in the condensed consolidated statements of cash flows. September 30, December 31, 2020 2019 2019 2018 Cash and cash equivalents $ 763,920 $ 580,329 $ 680,070 $ 544,358 Restricted cash included in prepaid expenses and other current assets 2,130 — — — Restricted cash included in other assets — 2,789 2,914 — Cash, cash equivalents and restricted cash in the condensed consolidated statements of cash flows $ 766,050 $ 583,118 $ 682,984 $ 544,358

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Assets And Liabilities Measured At Fair Value	The following table presents fair value information related to the Company's assets and liabilities measured at amortized cost on the condensed consolidated balance sheets with the exception of the interest rate swap, which is measured at fair value: Fair Value Measurements at September 30, 2020 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 269,955 $ 269,955 $ — $ — Commercial paper 126,563 — 126,563 — Corporate bonds 25,142 — 25,142 — U.S. Treasury and agency obligations 11,799 — 11,799 — Short-term investments: Corporate bonds 183,827 — 183,827 — Commercial paper 316,167 — 316,167 — U.S. Treasury and agency obligations 38,144 — 38,144 — Total $ 971,597 $ 269,955 $ 701,642 $ — Liabilities Long-term debt $ 39,436 $ — $ 39,436 $ — Interest rate swap 666 — 666 — Total $ 40,102 $ — $ 40,102 $ — Fair Value Measurements at December 31, 2019 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 155,080 $ 155,080 $ — $ — Commercial paper 54,712 — 54,712 — Short-term investments: Corporate bonds 259,422 259,422 — — Commercial paper 236,752 — 236,752 — Certificate of deposit 6,501 6,501 — — Long-term investments and other assets: Auction rate securities 592 — — 592 Interest rate swaps 13 — 13 — Total $ 713,072 $ 421,003 $ 291,477 $ 592 Liabilities Long-term debt $ 42,004 $ — $ 42,004 $ — Contingent purchase consideration 273 — — 273 Total $ 42,277 $ — $ 42,004 $ 273
Fair Value, Assets Measured on Recurring Basis	The following table presents information about the Company's movement in Level 3 assets and liabilities measured at fair value: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Auction rate securities Balance, beginning of period $ 596 $ 852 $ 592 $ 847 Redemptions (596) (264) (596) (264) Change in fair value and accretion — 2 4 7 Balance, end of period $ — $ 590 $ — $ 590 Contingent purchase consideration Balance, beginning of period $ — $ 300 $ 273 $ 898 Cash payments — — (272) (632) Foreign exchange adjustment — (3) (1) 31 Balance, end of period $ — $ 297 $ — $ 297
Fair Value, Liabilities Measured on Recurring Basis	The following table presents information about the Company's movement in Level 3 assets and liabilities measured at fair value: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Auction rate securities Balance, beginning of period $ 596 $ 852 $ 592 $ 847 Redemptions (596) (264) (596) (264) Change in fair value and accretion — 2 4 7 Balance, end of period $ — $ 590 $ — $ 590 Contingent purchase consideration Balance, beginning of period $ — $ 300 $ 273 $ 898 Cash payments — — (272) (632) Foreign exchange adjustment — (3) (1) 31 Balance, end of period $ — $ 297 $ — $ 297
Schedule of Effective Maturity Dates of Held To Maturity Investments	The following table presents the effective maturity dates of held-to-maturity and available-for-sale debt investments as of September 30, 2020 and December 31, 2019: September 30, 2020 December 31, 2019 Book Value Fair Value Book Value Fair Value Investment maturity Held-to-maturity: Less than 1 year $ 537,696 $ 538,138 $ 502,546 $ 502,675 Available-for-sale: Greater than 5 years $ — $ — $ 592 $ 592

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2020
Inventory Disclosure [Abstract]
Components of Inventories	Inventories consist of the following: September 30, December 31, 2020 2019 Components and raw materials $ 193,765 $ 200,390 Work-in-process 46,714 49,620 Finished components and devices 129,865 130,780 Total $ 370,344 $ 380,790

Goodwill And Intangibles (Table

Goodwill And Intangibles (Tables)	9 Months Ended
	Sep. 30, 2020
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table sets forth the changes in the carrying amount of goodwill: Nine Months Ended September 30, 2020 2019 Balance at January 1 $ 82,092 $ 100,722 Goodwill arising from business combinations — 9,426 Adjustment to goodwill during measurement period — 448 Foreign exchange adjustment 228 (642) Impairment losses (44,589) — Balance at September 30 $ 37,731 $ 109,954
Schedule of Intangible Assets	Intangible assets, subject to amortization, consisted of the following: September 30, 2020 December 31, 2019 Gross Accumulated Net Carrying Weighted- Average Lives Gross Carrying Accumulated Net Carrying Weighted- Customer relationships $ 57,897 $ (16,184) $ 41,713 11 years $ 57,866 $ (11,993) $ 45,873 11 years Technology, trademark and trade name 40,414 (19,527) 20,887 7 years 41,297 (16,128) 25,169 7 years Production know-how 9,250 (7,983) 1,267 7 years 9,180 (7,415) 1,765 7 years Patents 8,036 (6,904) 1,132 8 years 8,036 (6,572) 1,464 8 years Total $ 115,597 $ (50,598) $ 64,999 $ 116,379 $ (42,108) $ 74,271
Estimated Future Amortization Expense For Intangibles	The estimated future amortization expense for intangibles for the remainder of 2020 and subsequent years is as follows: 2020 (a) 2021 2022 2023 2024 Thereafter Total $ 2,939 $ 11,574 10,746 $ 9,858 $ 7,510 $ 22,372 $ 64,999 (a) For the three-month period beginning October 1, 2020.

Accrued Expenses And Other Li_2

Accrued Expenses And Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2020
Payables and Accruals [Abstract]
Components of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consist of the following: September 30, December 31, 2020 2019 Accrued compensation $ 57,265 $ 48,881 Contract liabilities 57,034 59,531 Current portion of accrued warranty 23,971 23,114 Short-term lease liabilities 5,573 5,300 Other 12,629 12,956 Total $ 156,472 $ 149,782

Product Warranties (Tables)

Product Warranties (Tables)	9 Months Ended
	Sep. 30, 2020
Product Warranties Disclosures [Abstract]
Summary of Product Warranty Activity	The following table summarizes product warranty accrual activity recorded during the nine months ended September 30, 2020 and 2019. 2020 2019 Balance at January 1 $ 48,866 $ 51,422 Provision for warranty accrual 16,255 16,916 Warranty claims (20,992) (17,399) Foreign currency translation 822 (1,077) Balance at September 30 $ 44,951 $ 49,862

Financing Arrangements (Tables)

Financing Arrangements (Tables)	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Borrowings Under Existing Financing Arrangements	The Company's borrowings under existing financing arrangements consist of the following: September 30, December 31, 2020 2019 Total notes payable $ 38,909 $ 41,708 Less: current portion (3,792) (3,740) Total long-term debt $ 35,117 $ 37,968
Schedule of Future Principal Payments	The future principal payments for the Company’s Notes as of September 30, 2020 are as follows: 2020 (a) $ 942 2021 3,810 2022 18,126 2023 16,031 Total $ 38,909 (a) For the three-month period beginning October 1, 2020.

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2020
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives	The fair value amounts in the condensed consolidated balance sheets were: September 30, December 31, 2020 2019 Notional amounts (1) $ 18,703 $ 19,594 Fair values: Other assets — 13 Deferred income taxes and other long-term liabilities 666 — (1) Notional amounts represent the gross contract/notional amount of the derivatives outstanding.
Derivative Gains (Losses) In The Consolidated Statements Of Income Related To Interest Rate Swap Contracts	The derivative gains and losses in the condensed consolidated financial statements for the three and nine months ended September 30, 2020 and 2019, related to the Company's current and previous interest rate swap contracts were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Effective portion recognized in other comprehensive income, pretax: Interest rate swap $ (723) $ 4 $ (679) $ 1

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Schedule of Unrecognized Tax Benefits	The following is a summary of the activity of the Company’s unrecognized tax benefits for nine months ended September 30, 2020 and 2019: 2020 2019 Balance at January 1, $ 11,416 $ 11,206 Additions for tax positions in current period 2,000 3,342 Foreign currency translation (938) (84) Balance at September 30, $ 12,478 $ 14,464

Net Income Attributable To IP_2

Net Income Attributable To IPG Photonics Corporation Per Share (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Computation of Diluted Net Income Per Share	The following table sets forth the computation of diluted net income attributable to IPG Photonics Corporation per share: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Net income attributable to IPG Photonics Corporation $ 35,604 $ 57,253 $ 110,233 $ 184,684 Net income attributable to common stockholders 35,604 57,253 110,233 184,684 Weighted average shares 53,098 52,928 53,136 53,073 Dilutive effect of common stock equivalents 566 694 555 791 Diluted weighted average common shares 53,664 53,622 53,691 53,864 Basic net income attributable to IPG Photonics Corporation per share $ 0.67 $ 1.08 $ 2.07 $ 3.48 Basic net income attributable to common stockholders $ 0.67 $ 1.08 $ 2.07 $ 3.48 Diluted net income attributable to IPG Photonics Corporation per share $ 0.66 $ 1.07 $ 2.05 $ 3.43 Diluted net income attributable to common stockholders $ 0.66 $ 1.07 $ 2.05 $ 3.43
Schedule of Antidilutive Securities Excluded from Computation of Earnings Per Share	The weighted average anti-dilutive shares outstanding for the three and nine months ended September 30, 2020 and 2019 were as follows: Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 Non-qualified stock options 528,300 763,000 555,800 578,000 Restricted stock units 28,900 167,200 36,200 149,200 Performance stock units — 45,500 19,800 40,800 Employee stock purchase plan 5,500 6,100 16,400 18,200 Total weighed average anti-dilutive shares outstanding 562,700 981,800 628,200 786,200

Basis Of Presentation And Sig_4

Basis Of Presentation And Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance, beginning of period	$ 1,999	$ 2,528	$ 2,547	$ 1,799
Provision for bad debts, net of recoveries	143	(27)	(206)	767
Uncollectable accounts written off	(1)	(3)	(72)	(91)
Foreign currency translation	(80)	(56)	(208)	(33)
Balance, end of period	$ 2,061	$ 2,442	$ 2,061	$ 2,442

Recent Accounting Pronounceme_3

Recent Accounting Pronouncements (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Sep. 30, 2020	Jan. 01, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable, net	$ 238,479	$ 240,352
Deferred income taxes, net	31,395	38,616
Retained earnings	$ 2,028,734	$ 2,138,852
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable, net	$ (148)
Deferred income taxes, net	33
Retained earnings	$ (115)
Cumulative Effect, Period of Adoption, Adjusted Balance
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable, net			$ 238,331
Deferred income taxes, net			31,428
Retained earnings			$ 2,028,619

Revenue From Contracts With C_3

Revenue From Contracts With Customers (Disaggregation of Revenue, By Application) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Sales by Application
Total	$ 318,441	$ 329,138	$ 864,094	$ 1,007,954
Materials processing
Sales by Application
Total	290,028	306,260	779,810	952,936
Other applications
Sales by Application
Total	$ 28,413	$ 22,878	$ 84,284	$ 55,018

Revenue From Contracts With C_4

Revenue From Contracts With Customers (Disaggregation of Revenue, By Product) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Total	$ 318,441	$ 329,138	$ 864,094	$ 1,007,954
High Power Continuous Wave ("CW") Lasers
Disaggregation of Revenue [Line Items]
Total	184,387	184,924	461,181	577,354
Medium Power CW Lasers
Disaggregation of Revenue [Line Items]
Total	11,756	11,891	33,701	42,904
Pulsed Lasers
Disaggregation of Revenue [Line Items]
Total	34,975	33,850	109,391	106,100
Quasi-Continuous Wave ("QCW") Lasers
Disaggregation of Revenue [Line Items]
Total	15,079	12,479	38,660	42,612
Laser and Non-Laser Systems
Disaggregation of Revenue [Line Items]
Total	20,841	32,929	64,417	104,943
Other Revenue including Amplifiers, Service, Parts, Accessories and Change in Deferred Revenue
Disaggregation of Revenue [Line Items]
Total	$ 51,403	$ 53,065	$ 156,744	$ 134,041

Revenue From Contracts With C_5

Revenue From Contracts With Customers (Disaggregation of Revenue, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Sales by Geography
Total	$ 318,441	$ 329,138	$ 864,094	$ 1,007,954
North America
Sales by Geography
Total	52,732	71,000	173,972	199,947
Germany
Sales by Geography
Total	16,163	17,204	51,208	59,487
Other including Eastern Europe/CIS
Sales by Geography
Total	54,907	62,196	158,686	192,527
China
Sales by Geography
Total	148,049	121,290	361,864	399,246
Japan
Sales by Geography
Total	12,884	21,859	41,241	54,879
Other
Sales by Geography
Total	31,227	28,877	70,924	89,544
Rest of World
Sales by Geography
Total	$ 2,479	$ 6,712	$ 6,199	$ 12,324

Revenue From Contracts With C_6

Revenue From Contracts With Customers (Disaggregation of Revenue, By Timing) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Timing of Revenue Recognition
Total	$ 318,441	$ 329,138	$ 864,094	$ 1,007,954
Goods and services transferred at a point in time
Timing of Revenue Recognition
Total	308,474	310,324	824,069	944,454
Goods and services transferred over time
Timing of Revenue Recognition
Total	$ 9,967	$ 18,814	$ 40,025	$ 63,500

Revenue From Contracts With C_7

Revenue From Contracts With Customers (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Concentration Risk [Line Items]
Revenue recognized that was included in the contract liability balance at the beginning of the period	$ 10,179	$ 4,534	$ 41,622	$ 40,786
One Customer | Customer Concentration Risk | Accounts Receivable
Concentration Risk [Line Items]
Concentration risk, percentage			35.00%		24.00%

Revenue From Contracts With C_8

Revenue From Contracts With Customers (Changes in Contract Assets and Contract Liabilities) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019	Dec. 31, 2018
Contract assets
Contract assets	$ 6,771	$ 10,606	$ 9,645	$ 10,102
Contract assets, change	(2,874)	504
Contract liabilities
Contract liabilities - current	57,034	49,358	59,531	52,606
Contract liabilities - current, change	(2,497)	(3,248)
Contract liabilities - long-term	2,121	1,677	$ 1,820	$ 1,413
Contract liabilities - long-term, change	$ 301	$ 264

Revenue From Contracts With C_9

Revenue From Contracts With Customers (Schedule of Remaining Performance Obligations) (Details) $ in Thousands	Sep. 30, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 33,799
Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	5,924
Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	27,875
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 12,373
Remaining performance obligations, expected timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 1,439
Remaining performance obligations, expected timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 10,934
Remaining performance obligations, expected timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 19,665
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 2,724
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 16,941
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 874
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 874
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 566
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 566
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 265
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 265
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 56
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 56
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year

Restricted Cash (Details)

Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Cash and Cash Equivalents [Abstract]
Cash and cash equivalents	$ 763,920	$ 680,070	$ 580,329	$ 544,358
Restricted cash included in prepaid expenses and other current assets	2,130	0	0	0
Restricted cash included in other assets	0	2,914	2,789	0
Cash, cash equivalents and restricted cash in the condensed consolidated statements of cash flows	$ 766,050	$ 682,984	$ 583,118	$ 544,358

Fair Value Measurements (Assets

Fair Value Measurements (Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets
Total	$ 971,597	$ 713,072
Liabilities
Long-term debt	39,436	42,004
Interest rate swap	666
Contingent purchase consideration		273
Total	40,102	42,277
Level 1
Assets
Total	269,955	421,003
Liabilities
Long-term debt	0	0
Interest rate swap	0
Contingent purchase consideration		0
Total	0	0
Level 2
Assets
Total	701,642	291,477
Liabilities
Long-term debt	39,436	42,004
Interest rate swap	666
Contingent purchase consideration		0
Total	40,102	42,004
Level 3
Assets
Total	0	592
Liabilities
Long-term debt	0	0
Interest rate swap	0
Contingent purchase consideration		273
Total	0	273
Money market fund deposits and term deposits
Assets
Cash equivalents	269,955	155,080
Money market fund deposits and term deposits | Level 1
Assets
Cash equivalents	269,955	155,080
Money market fund deposits and term deposits | Level 2
Assets
Cash equivalents	0	0
Money market fund deposits and term deposits | Level 3
Assets
Cash equivalents	0	0
Commercial paper
Assets
Cash equivalents	126,563	54,712
Commercial paper | Level 1
Assets
Cash equivalents	0	0
Commercial paper | Level 2
Assets
Cash equivalents	126,563	54,712
Commercial paper | Level 3
Assets
Cash equivalents	0	0
Corporate bonds
Assets
Cash equivalents	25,142
Short-term investments	183,827	259,422
Corporate bonds | Level 1
Assets
Cash equivalents	0
Short-term investments	0	259,422
Corporate bonds | Level 2
Assets
Cash equivalents	25,142
Short-term investments	183,827	0
Corporate bonds | Level 3
Assets
Cash equivalents	0
Short-term investments	0	0
U.S. Treasury and agency obligations
Assets
Cash equivalents	11,799
Short-term investments	38,144
U.S. Treasury and agency obligations | Level 1
Assets
Cash equivalents	0
Short-term investments	0
U.S. Treasury and agency obligations | Level 2
Assets
Cash equivalents	11,799
Short-term investments	38,144
U.S. Treasury and agency obligations | Level 3
Assets
Cash equivalents	0
Short-term investments	0
Commercial paper
Assets
Short-term investments	316,167	236,752
Commercial paper | Level 1
Assets
Short-term investments	0	0
Commercial paper | Level 2
Assets
Short-term investments	316,167	236,752
Commercial paper | Level 3
Assets
Short-term investments	$ 0	0
Certificate of deposit
Assets
Short-term investments		6,501
Certificate of deposit | Level 1
Assets
Short-term investments		6,501
Certificate of deposit | Level 2
Assets
Short-term investments		0
Certificate of deposit | Level 3
Assets
Short-term investments		0
Auction rate securities
Assets
Long-term investments and other assets		592
Auction rate securities | Level 1
Assets
Long-term investments and other assets		0
Auction rate securities | Level 2
Assets
Long-term investments and other assets		0
Auction rate securities | Level 3
Assets
Long-term investments and other assets		592
Interest rate swap
Assets
Long-term investments and other assets		13
Interest rate swap | Level 1
Assets
Long-term investments and other assets		0
Interest rate swap | Level 2
Assets
Long-term investments and other assets		13
Interest rate swap | Level 3
Assets
Long-term investments and other assets		$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	$ 971,597,000	$ 713,072,000
Long-term debt, fair value	39,436,000	42,004,000
Long-term debt, book value	38,909,000	41,708,000
Held-to-maturity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Allowance for credit loss	0
Held-to-maturity Securities | Short-term Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets fair value	538,138,000	502,675,000
Unrealized gain (loss)	$ 442,000	129,000
Available-for-sale Securities | Auction rate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale securities, cost basis		$ 592,000

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value of Auction Rate Securities and Contingent Purchase Consideration) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 596	$ 852	$ 592	$ 847
Redemptions	(596)	(264)	(596)	(264)
Change in fair value and accretion	0	2	4	7
Balance, end of period	0	590	0	590
Contingent purchase consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0	300	273	898
Cash payments	0	0	(272)	(632)
Foreign exchange adjustment	0	(3)	(1)	31
Balance, end of period	$ 0	$ 297	$ 0	$ 297

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Effective Maturity Dates of Held To Maturity Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Investment maturity
Held-to-maturity maturities, less than 1 year, book value	$ 537,696	$ 502,546
Held-to-maturity maturities, less than 1 year, fair value	538,138	502,675
Available-for-sale maturity, greater than 5 years, book value	0	592
Available-for-sale maturity, greater than 5 years, fair value	$ 0	$ 592

Inventories (Components Of Inve

Inventories (Components Of Inventories) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Inventory Disclosure [Abstract]
Components and raw materials	$ 193,765	$ 200,390
Work-in-process	46,714	49,620
Finished components and devices	129,865	130,780
Total	$ 370,344	$ 380,790

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Inventory Disclosure [Abstract]
Inventory provisions	$ 11,514	$ 7,303	$ 25,955	$ 19,952

Goodwill And Intangibles (Sched

Goodwill And Intangibles (Schedule of Changes) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Goodwill [Roll Forward]
Balance at January 1			$ 82,092	$ 100,722
Goodwill arising from business combinations			0	9,426
Adjustment to goodwill during measurement period			0	448
Foreign exchange adjustment			228	(642)
Impairment losses	$ (44,589)	$ 0	(44,589)	0
Balance at September 30	$ 37,731	$ 109,954	$ 37,731	$ 109,954

Goodwill And Intangibles (Narra

Goodwill And Intangibles (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Goodwill impairment	$ (44,589)	$ 0		$ (44,589)	$ 0
Amortization expense	$ 2,947	$ 3,617		$ 9,029	$ 10,581
Genesis Systems Group
Business Acquisition [Line Items]
Percentage of business acquired						100.00%
Working capital adjustment			$ 448

Goodwill And Intangibles (Intan

Goodwill And Intangibles (Intangible Assets) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 115,597	$ 116,379
Accumulated amortization	(50,598)	(42,108)
Net carrying amount	64,999	74,271
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	57,897	57,866
Accumulated amortization	(16,184)	(11,993)
Net carrying amount	$ 41,713	$ 45,873
Weighted-average lives	11 years	11 years
Technology, trademark and trade name
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 40,414	$ 41,297
Accumulated amortization	(19,527)	(16,128)
Net carrying amount	$ 20,887	$ 25,169
Weighted-average lives	7 years	7 years
Production know-how
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 9,250	$ 9,180
Accumulated amortization	(7,983)	(7,415)
Net carrying amount	$ 1,267	$ 1,765
Weighted-average lives	7 years	7 years
Patents
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount	$ 8,036	$ 8,036
Accumulated amortization	(6,904)	(6,572)
Net carrying amount	$ 1,132	$ 1,464
Weighted-average lives	8 years	8 years

Goodwill And Intangibles (Estim

Goodwill And Intangibles (Estimated Future Amortization Expense For Intangibles) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 2,939
2021	11,574
2022	10,746
2023	9,858
2024	7,510
Thereafter	22,372
Net carrying amount	$ 64,999	$ 74,271

Accrued Expenses And Other Li_3

Accrued Expenses And Other Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued compensation	$ 57,265	$ 48,881
Contract liabilities	57,034	59,531	$ 49,358	$ 52,606
Current portion of accrued warranty	23,971	23,114
Short-term lease liabilities	5,573	5,300
Other	12,629	12,956
Total	$ 156,472	$ 149,782

Product Warranties (Narrative)

Product Warranties (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019
Product Warranty Liability [Line Items]
Accrued warranty reported in accrued expenses and other liabilities	$ 23,971	$ 23,114
Accrued warranty reported in other long-term liabilities	$ 20,980	$ 25,752
Minimum
Product Warranty Liability [Line Items]
Service warranties on lasers and amplifiers	1 year
Maximum
Product Warranty Liability [Line Items]
Service warranties on lasers and amplifiers	5 years

Product Warranties (Summary Of

Product Warranties (Summary Of Product Warranty Activity) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Balance at January 1	$ 48,866	$ 51,422
Provision for warranty accrual	16,255	16,916
Warranty claims	(20,992)	(17,399)
Foreign currency translation	822	(1,077)
Balance at September 30	$ 44,951	$ 49,862

Financing Arrangements (Borrowi

Financing Arrangements (Borrowings Under Existing Financing Arrangements) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
Total notes payable	$ 38,909	$ 41,708
Less: current portion	(3,792)	(3,740)
Total long-term debt	$ 35,117	$ 37,968

Financing Arrangements (Narrati

Financing Arrangements (Narrative) (Details) € in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)	May 31, 2023USD ($)	Jul. 31, 2022USD ($)	Sep. 30, 2020EUR (€)	Dec. 31, 2019USD ($)
Debt Instrument [Line Items]
Total unused credit lines and overdraft facilities	$ 129,032,000
Unsecured Debt | Scenario, Forecast
Debt Instrument [Line Items]
Amount due on long-term note		$ 15,438,000
Unsecured Debt | Interest rate swap
Debt Instrument [Line Items]
Fixed interest rate swap	2.85%			2.85%
Unsecured Debt | London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Variable interest rate	1.20%
Secured Debt
Debt Instrument [Line Items]
Amount due on long-term note	$ 20,206,000
Current portion of long-term note	$ 2,604,000
Fixed interest rate swap	2.74%			2.74%
Secured Debt | Scenario, Forecast
Debt Instrument [Line Items]
Amount due on long-term note			$ 15,375,000
Long-term notes | Unsecured Debt
Debt Instrument [Line Items]
Amount due on long-term note	$ 18,703,000
Current portion of long-term note	1,188,000
U.S. line-of-credit
Debt Instrument [Line Items]
Line of credit	0				$ 0
Guarantees issued	3,066,000				1,426,000
Euro line-of-credit
Debt Instrument [Line Items]
Line of credit	0				0
Guarantees issued	3,866,000				1,422,000
Euro overdraft facility
Debt Instrument [Line Items]
Line of credit	0				$ 0
Letter of Credit | U.S. line-of-credit
Debt Instrument [Line Items]
Borrowing capacity	75,000,000
Letter of Credit | Euro line-of-credit
Debt Instrument [Line Items]
Borrowing capacity	58,619,000			€ 50,000
Letter of Credit | Euro overdraft facility
Debt Instrument [Line Items]
Borrowing capacity	$ 2,345,000			€ 2,000

Financing Arrangements (Future

Financing Arrangements (Future Principal Payments) (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Debt Disclosure [Abstract]
2020	$ 942
2021	3,810
2022	18,126
2023	16,031
Total notes payable	$ 38,909	$ 41,708

Derivative Financial Instrume_3

Derivative Financial Instruments (Fair Value) (Details) - Derivative designated as a cash flow hedge - Interest rate swap - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Derivatives, Fair Value [Line Items]
Derivative, notional amount	$ 18,703,000	$ 19,594,000
Other assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 666,000	$ 13,000

Derivative Financial Instrume_4

Derivative Financial Instruments (Derivative Gains (Losses) In The Consolidated Statements Of Income Related To Interest Rate Swap Contracts) (Details) - Interest rate swap - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recognized in other comprehensive income, pretax			$ (679)	$ 1
Derivative designated as a cash flow hedge
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recognized in other comprehensive income, pretax	$ (723)	$ 4

Commitments And Contingencies (

Commitments And Contingencies (Details)	Sep. 30, 2020USD ($)
Commitments and Contingencies Disclosure [Abstract]
Legal proceedings	$ 0

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	16.40%	26.20%	21.00%	24.80%
Discrete tax expense (benefit)	$ (727)	$ (5,443)	$ (6,658)	$ (8,357)
Equity based compensation, provisional income tax expense (benefit)	1,896	229	6,590	4,271
Provisional income tax expense (benefit)	1,586	$ 5,326	3,867	$ 5,293
Provision adjustment, tax effect of losses in subsidiaries	$ 2,641		$ 3,282

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1,	$ 11,416	$ 11,206
Additions for tax positions in current period	2,000	3,342
Foreign currency translation	(938)	(84)
Balance at September 30,	$ 12,478	$ 14,464

Net Income Attributable To IP_3

Net Income Attributable To IPG Photonics Corporation Per Share (Computation of Diluted Net Income) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share [Abstract]
Net income attributable to IPG Photonics Corporation	$ 35,604	$ 57,253	$ 110,233	$ 184,684
Net income attributable to common stockholders	$ 35,604	$ 57,253	$ 110,233	$ 184,684
Weighted average shares (in shares)	53,098	52,928	53,136	53,073
Dilutive effect of common stock equivalents (in shares)	566	694	555	791
Diluted weighted average common shares (in shares)	53,664	53,622	53,691	53,864
Basic net income attributable to IPG Photonics Corporation per share (in dollars per share)	$ 0.67	$ 1.08	$ 2.07	$ 3.48
Basic net income attributable to common stockholders (in dollars per share)	0.67	1.08	2.07	3.48
Diluted net income attributable to IPG Photonics Corporation per share (in dollars per share)	0.66	1.07	2.05	3.43
Diluted net income attributable to common stockholders (in dollars per share)	$ 0.66	$ 1.07	$ 2.05	$ 3.43

Net Income Attributable To IP_4

Net Income Attributable To IPG Photonics Corporation Per Share (Anti Dilutive Shares Excluded From EPS) (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded from computation of diluted weighted average common shares (in shares)	562,700	981,800	628,200	786,200
Stock Options | Non-qualified Plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded from computation of diluted weighted average common shares (in shares)	528,300	763,000	555,800	578,000
Restricted Stock Units, RSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded from computation of diluted weighted average common shares (in shares)	28,900	167,200	36,200	149,200
Performance Stock Units, PSUs
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded from computation of diluted weighted average common shares (in shares)	0	45,500	19,800	40,800
Employee Stock Purchase Plan, ESPP
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded from computation of diluted weighted average common shares (in shares)	5,500	6,100	16,400	18,200

Net Income Attributable to IP_5

Net Income Attributable to IPG Photonics Corporation Per Share (Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	May 05, 2020
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock repurchased during period, value	$ 9,654,000	$ 23,637,000	$ 37,884,000	$ 25,921,000
Decrease in weighted average number of shares outstanding treasury stock (in shares)	(22,842)		(155,372)
2019 Program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase authorized amount					$ 125,000,000
2020 Program
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase authorized amount					200,000,000
Stock repurchased during period (in shares)	61,472		301,660
Stock repurchase average price (in dollars per share)	$ 157.01		$ 125.58
Remaining repurchase amount	$ 246,000,000		$ 246,000,000
Share Repurchase Program 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Share repurchase authorized amount					$ 125,000,000

Subsequent Events (Details)

Subsequent Events (Details) - Subsequent Event - Pi-Tecnologia S.A. $ in Thousands	Oct. 01, 2020USD ($)
Equity, Class of Treasury Stock [Line Items]
Consideration transferred	$ 2,717
Payments to acquire businesses, gross	$ 906
Remainder of acquisition price, payment term	3 years