IPG Photonics (IPGP) 10-Q 5 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 01, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Period Focus	Q3
Document Fiscal Year Focus	2,018
Entity Registrant Name	IPG PHOTONICS CORP
Entity Central Index Key	1,111,928
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding (in shares)		53,400,171
Entity Emerging Growth Company	false
Entity Small Business	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
CURRENT ASSETS:
Cash and cash equivalents	$ 647,606	$ 909,900
Short-term investments	474,422	206,257
Accounts receivable, net	251,613	237,278
Inventories	397,409	307,712
Prepaid income taxes	61,222	44,944
Prepaid expenses and other current assets	50,013	47,919
Total current assets	1,882,285	1,754,010
DEFERRED INCOME TAXES, NET	19,995	26,976
GOODWILL	56,769	55,831
INTANGIBLE ASSETS, NET	45,844	51,223
PROPERTY, PLANT AND EQUIPMENT, NET	529,163	460,206
OTHER ASSETS	28,043	19,009
TOTAL ASSETS	2,562,099	2,367,255
CURRENT LIABILITIES:
Current portion of long-term debt	3,654	3,604
Accounts payable	29,494	35,109
Accrued expenses and other liabilities	137,060	144,417
Income taxes payable	47,777	15,773
Total current liabilities	217,985	198,903
DEFERRED INCOME TAXES AND OTHER LONG-TERM LIABILITIES	94,675	100,652
LONG-TERM DEBT, NET OF CURRENT PORTION	42,631	45,378
Total liabilities	355,291	344,933
COMMITMENTS AND CONTINGENCIES (NOTE 11)
IPG PHOTONICS CORPORATION EQUITY:
Common stock, $0.0001 par value, 175,000,000 shares authorized; 54,362,579 and 53,398,504 shares issued and outstanding, respectively, at June 30, 2018; 54,007,708 and 53,629,439 shares issued and outstanding, respectively, at December 31, 2017	5	5
Treasury stock, at cost (964,075 and 378,269 shares held)	(160,859)	(48,933)
Additional paid-in capital	738,285	704,727
Retained earnings	1,772,941	1,443,867
Accumulated other comprehensive loss	(144,409)	(77,344)
Total IPG Photonics Corporation equity	2,205,963	2,022,322
NONCONTROLLING INTERESTS	845	0
Total equity	2,206,808	2,022,322
TOTAL LIABILITIES AND EQUITY	$ 2,562,099	$ 2,367,255

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Sep. 30, 2018	Dec. 31, 2017
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)	54,362,579	54,007,708
Common stock, shares outstanding (in shares)	53,398,504	53,629,439
Treasury stock, shares (in shares)	964,075	378,269

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
NET SALES	$ 356,346	$ 392,615	$ 1,129,823	$ 1,047,834
COST OF SALES	161,162	168,060	496,303	459,716
GROSS PROFIT	195,184	224,555	633,520	588,118
OPERATING EXPENSES:
Sales and marketing	13,479	13,384	41,531	36,347
Research and development	30,909	25,541	91,268	74,281
General and administrative	25,245	21,491	74,857	59,092
Loss (gain) on foreign exchange	1,688	3,917	(1,489)	15,553
Total operating expenses	71,321	64,333	206,167	185,273
OPERATING INCOME	123,863	160,222	427,353	402,845
OTHER INCOME (EXPENSE), Net:
Interest income, net	3,884	(125)	4,925	651
Other income (expense), net	423	459	1,252	(47)
Total other income	4,307	334	6,177	604
INCOME BEFORE PROVISION FOR INCOME TAXES	128,170	160,556	433,530	403,449
PROVISION FOR INCOME TAXES	(27,418)	(44,959)	(104,827)	(108,817)
NET INCOME	100,752	115,597	328,703	294,632
LESS: NET INCOME (LOSS) ATTRIBUTABLE TO NONCONTROLLING INTERESTS	235	0	235	(26)
NET INCOME ATTRIBUTABLE TO IPG PHOTONICS CORPORATION	$ 100,517	$ 115,597	$ 328,468	$ 294,658
NET INCOME ATTRIBUTABLE TO IPG PHOTONICS CORPORATION PER SHARE:
Basic (in dollars per share)	$ 1.88	$ 2.16	$ 6.12	$ 5.51
Diluted (in dollars per share)	$ 1.84	$ 2.11	$ 5.97	$ 5.40
WEIGHTED AVERAGE SHARES OUTSTANDING:
Basic (in shares)	53,571	53,440	53,677	53,453
Diluted (in shares)	54,696	54,698	54,995	54,570

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 100,752	$ 115,597	$ 328,703	$ 294,632
Other comprehensive income, net of tax:
Translation adjustments	(15,047)	29,855	(67,072)	89,076
Unrealized loss on derivatives, net of tax	(5)	11	(3)	(35)
Effect of adopted accounting standards	0	0	10	0
Available-for-sale investments, net of tax, reclassified to net income	0	0	0	298
Total other comprehensive (loss) income	(15,052)	29,866	(67,065)	89,339
Comprehensive income	85,700	145,463	261,638	383,971
Comprehensive income (loss) attributable to noncontrolling interests	196	0	196	(26)
Comprehensive income attributable to IPG Photonics Corporation	$ 85,504	$ 145,463	$ 261,442	$ 383,997

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 328,703	$ 294,632
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	58,894	46,416
Deferred income taxes	2,954	14,534
Stock-based compensation	21,443	16,989
Unrealized (gain) loss on foreign currency transactions	(1,779)	8,197
Other	(1,936)	699
Provisions for inventory, warranty & bad debt	30,582	34,690
Changes in assets and liabilities that (used) provided cash:
Accounts receivable	(26,058)	(56,416)
Inventories	(122,051)	(39,697)
Prepaid expenses and other current assets	(4,925)	(1,560)
Accounts payable	(1,319)	3,423
Accrued expenses and other liabilities	(20,095)	1,809
Income and other taxes payable	15,838	(26,866)
Net cash provided by operating activities	280,251	296,850
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of and deposits on property, plant and equipment	(133,355)	(99,221)
Proceeds from sales of property, plant and equipment	755	15,437
Purchases of investments	(566,498)	(146,585)
Proceeds from sales and maturities of investments	286,346	188,143
Acquisitions of businesses, net of cash acquired	(4,423)	(50,594)
Other	307	(496)
Net cash used in investing activities	(416,868)	(93,316)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from line-of-credit facilities	255	6,761
Payments on line-of-credit facilities	(255)	(6,761)
Purchase of noncontrolling interests	0	(197)
Proceeds on long-term borrowings	0	28,000
Principal payments on long-term borrowings	(2,696)	(18,951)
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	12,115	23,296
Cash contributed by noncontrolling interests	378	0
Purchase of treasury stock, at cost	(111,926)	(26,911)
Net cash (used in) provided by financing activities	(102,129)	5,237
EFFECT OF CHANGES IN EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	(23,548)	47,641
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(262,294)	256,412
CASH AND CASH EQUIVALENTS — Beginning of period	909,900	623,855
CASH AND CASH EQUIVALENTS — End of period	647,606	880,267
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	2,402	1,965
Cash paid for income taxes	94,801	118,660
Non-cash transactions:
Demonstration units transferred from inventory to other assets	3,787	3,290
Inventory transferred to machinery and equipment	2,114	4,087
Changes in accounts payable related to property, plant and equipment	$ (3,337)	$ (15)

Consolidated Statements Of Equi

Consolidated Statements Of Equity - USD ($) $ in Thousands	Total	TOTAL IPG PHOTONICS CORPORATION EQUITY	COMMON STOCK	TREASURY STOCK	ADDITIONAL PAID-IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE LOSS	NONCONTROLLING INTERESTS ("NCI")
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adopted accounting standards					$ 2,078	$ 2,145
Balance, beginning of year (in shares) at Dec. 31, 2016			(53,251,805)	(102,774)
Balance, beginning of year at Dec. 31, 2016			$ 5	$ (8,946)	650,974	1,094,108	$ (178,583)	$ 166
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and conversion of restricted stock units (in shares)			543,547
Exercise of stock options and conversion of restricted stock units			$ 0
Common stock issued under employee stock purchase plan (in shares)			19,882
Common stock issued under employee stock purchase plan			$ 0		1,669
Purchased common stock (in shares)			(215,860)	(215,860)
Purchased common stock			$ 0	$ (26,911)
Stock-based compensation					16,989
Common stock issued under employee stock option plan, net of shares withheld for employee taxes					21,627
Net income attributable to IPG Photonics Corporation	$ 294,658					294,658
Translation adjustments	89,076						89,023	57
Unrealized loss on derivatives, net of tax	(35)						(35)
Unrealized loss on available-for-sale investments, net of tax	298						(240)
Realized loss on available-for-sale investments, net of tax, reclassified to net income							538
Noncontrolling interest of acquired company								(197)
Net income (loss) attributable to NCI	(26)							(26)
Balance, end of period (in shares) at Sep. 30, 2017			(53,599,374)	(318,634)
Balance, end of period at Sep. 30, 2017	1,959,099	$ 1,959,099	$ 5	$ (35,857)	693,337	1,390,911	(89,297)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Effect of adopted accounting standards					0	606	10
Balance, beginning of year (in shares) at Dec. 31, 2017			(53,629,439)	(378,269)
Balance, beginning of year at Dec. 31, 2017	2,022,322		$ 5	$ (48,933)	704,727	1,443,867	(77,344)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and conversion of restricted stock units (in shares)			342,673
Exercise of stock options and conversion of restricted stock units			$ 0
Common stock issued under employee stock purchase plan (in shares)			12,198
Common stock issued under employee stock purchase plan			$ 0		2,288
Purchased common stock (in shares)			(585,806)	(585,806)
Purchased common stock			$ 0	$ (111,926)
Stock-based compensation					21,443
Common stock issued under employee stock option plan, net of shares withheld for employee taxes					9,827
Net income attributable to IPG Photonics Corporation	328,468					328,468
Translation adjustments	(67,072)						(67,072)	(39)
Unrealized loss on derivatives, net of tax	(3)						(3)
Unrealized loss on available-for-sale investments, net of tax	0						0
Realized loss on available-for-sale investments, net of tax, reclassified to net income							0
Noncontrolling interest of acquired company								649
Net income (loss) attributable to NCI	235							235
Balance, end of period (in shares) at Sep. 30, 2018			(53,398,504)	(964,075)
Balance, end of period at Sep. 30, 2018	$ 2,206,808	$ 2,205,963	$ 5	$ (160,859)	$ 738,285	$ 1,772,941	$ (144,409)	$ 845

Basis Of Presentation And Signi

Basis Of Presentation And Significant Accounting Policies	9 Months Ended
	Sep. 30, 2018
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 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 consolidated financial statements include the Company's accounts and those of its subsidiaries. All intercompany balances have been eliminated in consolidation. These 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, 2017. In the opinion of the Company's management, the unaudited 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 consolidated financial statements are not necessarily indicative of results that may be expected for the entire year. The Company has evaluated subsequent events through the time of filing this Quarterly Report on Form 10-Q with the SEC. In accordance with the Financial Accounting Standards Board ("FASB") Accounting Standards Codification ("ASC") 606, "Revenue from Contracts with Customers," ("ASC 606" or the "new revenue standard"), the following significant accounting policies have been adopted as of January 1, 2018. Revenue Recognition — Revenue is recognized when transfer of control to the customer occurs in an amount reflecting the consideration that the Company expects to be entitled. In order to achieve this core principle, the Company applies the following five step approach: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. The Company considers customer purchase orders, which in some cases are governed by master sales agreements, to be the contracts with a customer. As part of its consideration of the contract, the Company evaluates certain factors including the customer's ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct as the identified performance obligations. In determining the transaction price, the Company evaluates whether the price is subject to refund or adjustment to determine the net consideration to which the Company expects to be entitled. As the Company's standard payment terms are less than one year, the Company has elected the practical expedient under ASC 606-10-32-18 to not assess whether a contract has a significant financing component. The Company allocates the transaction price to each distinct product based on its relative standalone selling price. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company's performance obligation is satisfied), which typically occurs at shipment. The Company often receives orders with multiple delivery dates that may extend across several reporting periods. The Company allocates the transaction price of the contract to each delivery based on the product standalone selling price. The Company invoices for each scheduled delivery upon shipment and recognizes revenues for such delivery at that point, assuming transfer of control has occurred. As scheduled delivery dates are generally within 1 year, under the optional exemption provided by ASC 606-10-50-14 revenues allocated to future shipments of partially completed contracts are not disclosed. Rights of return generally are not included in customer contracts. Accordingly, upon application of steps one through five above, product revenue is recognized upon shipment and transfer of control. Returns are infrequent and are recorded as a reduction of revenue. In certain subsidiaries the Company provides sales commissions to sales representatives based on sales volume. The Company has determined that the incentive portion of its sales commissions qualify as contract costs. The Company has elected the practical expedient in ASC 340-40-25-4 to expense sales commissions when incurred as the amortization period of the asset that would otherwise have been recognized is one year or less. Revenue Recognition at a Point in Time — Revenues recognized at a point in time consist primarily of product, installation and service sales. The Company sells products to original equipment manufacturers ("OEMs") that supply materials processing laser systems, communications systems, medical laser systems and other laser systems for advanced applications to end users. The Company also sells products to end users that use IPG products directly to build their own systems, which incorporate IPG products or use IPG products as an energy or light source. The Company recognizes revenue for laser and spare part sales following the transfer of control of such products to the customer, which typically occurs upon shipment or delivery depending on the terms of the underlying contracts. Installation revenue is recognized upon completion of the installation service, which typically occurs within 90 days of delivery. For laser systems that carry customer specific processing requirements, revenue is recognized at the latter of customer acceptance date or shipment date if the customer acceptance is made prior to shipment. When sales contracts contain multiple performance obligations, such as the shipment or delivery of products and installation, the Company allocates the transaction price to each performance obligation identified in the contract based on relative standalone selling prices and recognizes the related revenue as control of each individual product or service is transferred to the customer, in satisfaction of the corresponding performance obligations. Revenue Recognition over Time — The Company offers extended warranty agreements, which extend the standard warranty periods. Warranties are limited and provide that the product meets specifications and is free from defects in materials and workmanship. Extended warranties are sold separately from products and represent a distinct performance obligation. Revenue related to the performance obligation for extended warranties is recognized over time as the customer simultaneously receives and consumes the benefits provided by the Company. The customer receives the assurance that the product will operate in accordance with agreed-upon specifications evenly during the extended warranty period regardless of whether they make a claim during that period, and therefore, revenue at time of sale is deferred and recognized over the time period of the extended warranty period. Customer Deposits and Deferred Revenue — When the Company receives consideration from a customer or such consideration is unconditionally due prior to transferring goods or services under the terms of a sales contract, the Company records customer deposits or deferred revenue, which represent contract liabilities. The Company recognizes 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. Reclassifications —

Recent Accounting Pronouncement

Recent Accounting Pronouncements	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS Adopted Pronouncements — On January 1, 2018, the Company adopted ASC 606 and all related amendments using the modified retrospective method for contracts that were not completed as of the date of initial application. The Company recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. The Company expects the impact of the adoption of the new standard to be immaterial to net income on an ongoing basis. A majority of revenue continues to be recognized at a point in time when control transfers based on the terms of underlying contact. Under the new revenue standard, the Company changed from deferring revenue for installation services in an amount equal to the greater of the cash received related to installation or the fair value to deferring the standalone selling price for these services. In February 2018, the FASB issued ASU No. 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income" ("ASU 2018-02"). ASU 2018-02 allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act ("the Act"). The Company adopted this standard during the first quarter of 2018, which resulted in the reclassification of $10 related to the tax effect of unrealized gains on derivatives. In October 2016, the FASB issued ASU No. 2016-16, "Income Taxes (Topic 740) - Intra-Entity Transfers of Assets other than Inventory" ("ASU 2016-16"). ASU 2016-16 eliminates the current exception that prohibits the recognition of current and deferred income tax consequences for intra-entity asset transfers (other than inventory) until the asset has been sold to an outside party. The amendments have been applied on a modified retrospective basis through a cumulative effect adjustment to retained earnings. The Company adopted this standard during the first quarter of 2018, which resulted in the reclassification of prepaid income taxes, deferred income taxes and retained earnings. The cumulative effect of the changes made to the Company's consolidated January 1, 2018 balance sheet for the adoption of ASC 606, ASU 2018-02 and ASU 2016-16 was as follows: Balance at Adoption of Adoption of Adoption of Balance at 12/31/2017 ASC 606 ASU 2018-02 ASU 2016-16 1/1/2018 Balance Sheet Prepaid income taxes $ 44,944 $ — $ — $ (1,203) $ 43,741 Deferred income tax assets 26,976 (55) — 1,229 28,150 Customer deposits and deferred revenue (short-term) 47,324 (816) — — 46,508 Income taxes payable 15,773 37 — — 15,810 Deferred income tax liabilities 21,362 134 — — 21,496 Retained earnings 1,443,867 590 (10) 26 1,444,473 Accumulated other comprehensive loss (77,344) — 10 — (77,334) In January 2017, the FASB issued ASU No. 2017-04, "Intangibles—Goodwill and Other (Topic 350)" ("ASU 2017-04"). ASU 2017-04 simplifies the accounting for goodwill impairments by eliminating step 2 from the goodwill impairment test. The amendments are applied prospectively upon adoption. The Company early adopted this standard during the first quarter of 2018. The Company performs its annual goodwill impairment assessment on October 1 of each year. The new impairment test will be used in the annual assessment or if events or changes in circumstances indicate that the carrying amount may not be recoverable and an impairment analysis is performed. Other Pronouncements Currently Under Evaluation — In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02" or "the new lease standard"). ASU 2016-02 requires a lessee to recognize assets and liabilities on the balance sheet for leases with lease terms greater than twelve months. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. In July 2018, the FASB issued ASU 2018-11, which provides an additional transition method for implementing the new lease standard. The Company will adopt the provisions of ASU 2018-11 by applying the standard at the adoption date and recognizing a cumulative-effect adjustment. The Company is currently completing its review of the lease population and is in the process of implementing a software solution to assist with lease accounting and evaluating footnote disclosures. The Company does not expect that the standard will have a material effect on its consolidated financial statements upon adoption. In June 2018, the FASB issued ASU No. 2018-07, "Compensation - Stock Compensation (Topic 718)" ("ASU 2018-07"). ASU 2018-07 aligns the accounting for share-based payments issued to employees and non-employees. ASU 2018-07 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating the standard but does not expect that it will have a material effect on its consolidated financial statements upon adoption.

Revenue From Contracts With Cus

Revenue From Contracts With Customers	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Revenue From Contracts With Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS The following tables represent a disaggregation of revenue from contracts with customers for the three and nine months ended September 30, 2018: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Sales by Application Materials processing $ 334,498 $ 1,065,712 Other applications 21,848 64,111 Total $ 356,346 $ 1,129,823 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Sales by Product High Power Continuous Wave ("CW") Lasers $ 227,462 $ 724,111 Medium Power CW Lasers 15,825 65,092 Low Power CW Lasers 3,276 10,380 Pulsed Lasers 35,408 115,243 Quasi-Continuous Wave ("QCW") Lasers 18,276 54,568 Other Revenue including Amplifiers, Laser Systems, Service, Parts, Accessories and Change in Deferred Revenue 56,099 160,429 Total $ 356,346 $ 1,129,823 Sales by Geography United States and other North America $ 53,762 $ 140,704 Europe: Germany 21,714 86,939 Other including Eastern Europe/CIS 66,392 225,717 Asia and Australia: China 158,853 511,852 Japan 21,871 60,927 Other 31,953 99,476 Rest of World 1,801 4,208 Total $ 356,346 $ 1,129,823 Timing of Revenue Recognition Goods and services transferred at a point in time $ 355,191 $ 1,126,285 Services transferred over time 1,155 3,538 Total $ 356,346 $ 1,129,823 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 is met. The Company bills customers for extended warranties upon entering into the agreement with the customer, resulting in deferred revenue. Revenue is recognized ratably over the term of the extended warranty agreement as the customer receives and consumes the benefits of such services. Before the transition date (under ASC 605, Revenue Recognition ), the Company deferred revenue for installation services in an amount equal to the greater of the cash received or the fair value for installation. Under the new revenue standard, the standalone selling price for installation services is deferred until control has transferred. The standalone selling price for installation services is determined based on the estimated number of days of service technician time required for installation at standard service rates. The impact of applying ASC 606 was a decrease in revenue recognized during the three months ended September 30, 2018 of $37 and a decrease for the nine months ended September 30, 2018 of $84 as compared to revenue accounted for under ASC 605. The following table reflects the changes in the Company's contract liabilities for the nine months ended September 30, 2018: September 30, January 1, 2018 2018 Change Contract liabilities Customer deposits $ 36,967 $ 36,937 $ 30 0.1 % Deferred revenue - current 11,307 9,571 1,736 18.1 % Deferred revenue - long-term 1,374 182 1,192 654.9 % During the three and nine months ended September 30, 2018, the Company recognized revenue of $3,355 and $38,885, respectively, that was included in the customer deposits and deferred revenue balances at the beginning of the period. The following table represents the Company's remaining performance obligations for sales of installation services and extended warranties and contracts with customer acceptance provisions included in deferred revenue as of September 30, 2018: Remaining Performance Obligations 2018 2019 2020 2021 2022 2023 Total Revenue expected to be recognized upon customer acceptance $ 7,443 $ 24 $ 3 $ — $ — $ — $ 7,470 Revenue expected to be recognized on contracts for installation services 246 236 — — — — 482 Revenue expected to be recognized for extended warranty agreements 1,165 1,910 576 349 178 60 4,238 Revenue deferred based on volume discount incentives — 491 — — — — 491 Total $ 8,854 $ 2,661 $ 579 $ 349 $ 178 $ 60 $ 12,681

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The Company's financial instruments consist of cash equivalents, short-term and long-term investments, accounts receivable, accounts payable, drawings on revolving lines of credit, long-term debt, contingent purchase consideration, and an interest rate swap. 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 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 Company's bond securities are reported at fair value based upon quoted prices for instruments with identical terms in active markets. The Company's commercial paper securities reported at fair value are based upon model-driven valuations in which all significant inputs are observable or can be derived from or corroborated by observable market data for substantially the full term of the asset or liability, and are therefore classified as Level 2. At September 30, 2018 and December 31, 2017, the Company's long-term debt consisted of a variable rate long-term note and a fixed rate long-term note. The book value of the long-term notes approximates the fair market value. The following table presents information about the Company's assets and liabilities measured at fair value: Fair Value Measurements at September 30, 2018 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 316,442 $ 316,442 $ — $ — U.S. Treasury and agency obligations 8,999 8,999 — — Commercial paper 89,312 — 89,312 — Short-term investments U.S. Treasury and agency obligations 113,094 113,094 — — Corporate bonds 196,856 196,856 — — Commercial paper 164,255 — 164,255 — Long-term investments and other assets: Corporate bonds 13,771 13,771 — — Auction rate securities 967 — — 967 Interest rate swap 13 — 13 — Total $ 903,709 $ 649,162 $ 253,580 $ 967 Liabilities Long-term debt $ 46,285 $ — $ 46,285 $ — Contingent purchase consideration 902 — — 902 Total $ 47,187 $ — $ 46,285 $ 902 Fair Value Measurements at December 31, 2017 Total Level 1 Level 2 Level 3 Assets Cash equivalents Money market fund deposits and term deposits $ 425,917 $ 425,917 $ — $ — Short-term investments U.S. Treasury and agency obligations 41,217 41,217 — — Corporate bonds 131,048 131,048 — — Commercial paper 33,896 33,896 — — Long-term investments and other assets: Auction rate securities 1,016 — — 1,016 Interest rate swaps 16 — 16 — Total $ 633,110 $ 632,078 $ 16 $ 1,016 Liabilities Long-term debt $ 48,982 $ — $ 48,982 $ — Contingent purchase consideration 902 — — 902 Total $ 49,884 $ — $ 48,982 $ 902 The fair value of the short-term investments considered held-to-maturity as of September 30, 2018 and December 31, 2017 was $474,205 and $206,161, respectively, which represents an unrealized loss of $(217) and $(96), respectively, as compared to the book value recorded on the Consolidated Balance Sheets for the same periods. The fair value of the long-term investments considered held-to-maturity as of September 30, 2018 was $14,738, which represented an unrealized gain of $118, as compared to the book value of $14,620 recorded within Other Assets on the Consolidated Balance Sheets for the same period. The fair value of the interest rate swap considered pricing models whose inputs are observable for the securities held by the Company. The fair value of the auction rate securities was determined using prices observed in inactive markets with limited observable data for the securities held by the Company. The fair value of contingent purchase consideration 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 purchase 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, 2018 2017 2018 2017 Auction rate securities Balance, beginning of period $ 1,174 $ 1,148 $ 1,016 $ 1,144 Period transactions (207) (138) (207) (138) Change in fair value and accretion — 2 158 6 Balance, end of period $ 967 $ 1,012 $ 967 $ 1,012 Contingent purchase consideration Balance, beginning of period $ 902 $ — $ 902 $ — Balance, end of period $ 902 $ — $ 902 $ — The following table presents the effective maturity dates of held-to-maturity debt investments as of September 30, 2018 and December 31, 2017: September 30, 2018 December 31, 2017 Book Value Fair Value Book Value Fair Value Investment maturity Less than 1 year $ 572,815 $ 572,516 $ 206,161 $ 206,161 1 through 5 years 13,776 13,771 — — Greater than 5 years 844 967 1,016 1,016 Total $ 587,435 $ 587,254 $ 207,177 $ 207,177

Inventories

Inventories	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following: September 30, December 31, 2018 2017 Components and raw materials $ 240,635 $ 145,261 Work-in-process 40,763 43,646 Finished components and devices 116,011 118,805 Total $ 397,409 $ 307,712

Goodwill And Intangibles

Goodwill And Intangibles	9 Months Ended
	Sep. 30, 2018
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 for the nine months ended September 30, 2018: Amounts Balance at January 1 $ 55,831 Goodwill arising from acquisition 4,072 Adjustment to goodwill during measurement period (2,948) Foreign exchange adjustment (186) Balance at September 30 $ 56,769 Intangible assets, subject to amortization, consisted of the following: September 30, 2018 December 31, 2017 Gross Carrying Accumulated Net Carrying Weighted- Average Lives Gross Carrying Accumulated Net Carrying Weighted- Patents $ 8,036 $ (5,893) $ 2,143 8 Years $ 8,036 $ (5,486) $ 2,550 8 Years Customer relationships 25,577 (5,603) 19,974 11 Years 26,768 (5,584) 21,184 11 Years Production know-how 6,768 (5,595) 1,173 8 Years 6,820 (5,035) 1,785 8 Years Technology, trademark and trade names 32,358 (9,804) 22,554 7 Years 32,564 (6,860) 25,704 8 Years Total $ 72,739 $ (26,895) $ 45,844 $ 74,188 $ (22,965) $ 51,223 During the second quarter of 2018, the Company acquired 100% of the shares of robot concept GmbH ("RC"). RC is located near Munich, Germany, and is an integrator of laser-based systems. The Company paid $4,453 to acquire RC, which represents the fair value on that date. Any excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed is allocated to goodwill, which amounted to $4,072. The goodwill arising from the acquisition will not be deductible for tax purposes. As a result of the acquisition, the Company recorded intangible assets of $104 related to trademark and trade name with a weighted-average useful life of 1 year and $557 related to customer relationships with a weighted-average life of 10 years. Amortization expense for the three months ended September 30, 2018 and 2017 was $1,982 and $1,725, respectively. Amortization for the nine months ended September 30, 2018 and 2017 was $5,821 and $3,958, respectively. The estimated future amortization expense for intangibles for the remainder of 2018 and subsequent years is as follows: 2018 2019 2020 2021 2022 Thereafter Total $ 1,870 $ 7,400 $ 6,747 $ 6,574 $ 5,775 $ 17,478 $ 45,844

Accrued Expenses And Other Liab

Accrued Expenses And Other Liabilities	9 Months Ended
	Sep. 30, 2018
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, 2018 2017 Accrued compensation $ 57,037 $ 63,203 Customer deposits and deferred revenue 48,274 47,324 Current portion of accrued warranty 22,045 25,059 Other 9,704 8,831 Total $ 137,060 $ 144,417

Product Warranties

Product Warranties	9 Months Ended
	Sep. 30, 2018
Product Warranties Disclosures [Abstract]
Product Warranties	PRODUCT WARRANTIES The Company typically provides 1 to 3-year parts and service warranties on lasers and amplifiers. Most of the Company's sales offices provide support to customers in their respective geographic areas. Warranty reserves have generally been sufficient to cover product warranty repair and replacement costs. The following table summarizes product warranty accrual activity recorded during the nine months ended September 30, 2018 and 2017. 2018 2017 Balance at January 1 $ 47,517 $ 33,978 Provision for warranty accrual 19,050 20,284 Warranty claims (13,827) (11,746) Foreign currency translation (1,057) 2,459 Balance at September 30 $ 51,683 $ 44,975 Accrued warranty reported in the accompanying consolidated financial statements as of September 30, 2018 and December 31, 2017 consisted of $22,045 and $25,059 in accrued expenses and other liabilities and $29,638 and $22,458 in other long-term liabilities, respectively.

Financing Arrangements

Financing Arrangements	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Financing Arrangements	FINANCING ARRANGEMENTS The Company's borrowings under existing financing arrangements consist of the following: September 30, December 31, 2018 2017 Long-term notes 46,285 48,982 Less: current portion (3,654) (3,604) Total long-term debt $ 42,631 $ 45,378 At September 30, 2018, the Company has an unsecured long-term note with an outstanding principal balance $21,078, of which, $1,188 is the current portion. The interest on this unsecured long-term note is variable at 1.2% above LIBOR and is fixed using an interest rate swap at 2.9% 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, 2018, the Company has another long-term note that is secured by its corporate aircraft with a outstanding principal balance of $25,207, of which, $2,466 is the current portion. The interest on this collateralized long-term note is fixed at 2.7% per annum. The collateralized long-term note matures in July 2022, at which time the outstanding principal balance will be $15,375.

Derivative Financial Instrument

Derivative Financial Instruments	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	DERIVATIVE FINANCIAL INSTRUMENTS Derivative instruments – The Company's primary market exposures are to interest rates and foreign exchange rates. The Company from time to time may use certain derivative financial instruments to help manage these exposures. The Company executes these instruments with financial institutions it judges to be credit-worthy. The Company does not hold or issue derivative financial instruments for trading or speculative purposes. The Company recognizes all derivative financial instruments as either assets or liabilities at fair value in the consolidated balance sheets. During the second quarter of 2018, the Company entered into foreign currency forward contracts to hedge the value of intercompany dividends declared in Euros by the Company's German subsidiary. The dividends were paid in the second and third quarters of 2018. These contracts were not designated as hedging instruments for accounting purposes. There are no foreign currency forward contracts outstanding at September 30, 2018. The Company also has an interest rate swap that is classified as a cash flow hedge of its variable rate debt. The fair value amounts in the consolidated balance sheets were: Notional Amounts 1 Other Assets Other Current Liabilities September 30, December 31, September 30, December 31, September 30, December 31, 2018 2017 2018 2017 2018 2017 Derivative designated as a cash flow hedge: Interest rate swap $ 21,078 $ 21,969 $ 13 $ 16 $ — $ — (1) Notional amounts represent the gross contract/notional amount of the derivatives outstanding. Gains associated with derivative instruments not designated as hedging instruments are as follows: Three Months Ended September 30, Nine Months Ended September 30, Classification 2018 2017 2018 2017 Gain (loss) recognized in income Gain (loss) on foreign exchange $ 1,169 $ — $ (19) $ — The following table reflects the effect of the interest rate swap contract designated as a cash flow hedging instrument in the Company's financial statements: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Effective portion recognized in other comprehensive income, pretax: Interest rate swap $ (5) $ (7) $ (3) $ (47)

Commitments And Contingencies

Commitments And Contingencies	9 Months Ended
	Sep. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES From 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

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES The effective tax rates for the three months ended September 30, 2018 and 2017 were 21.4% and 28.0%, respectively. For the nine months ended September 30, 2018 and 2017, the effective tax rates were 24.2% and 27.0%, respectively. The reduction in the tax rate is partially due to the reduction in the U.S. statutory tax rate to 21%. There were discrete tax benefits of $660 and $5,714 for the three months ended September 30, 2018 and 2017, respectively, and $5,178 and $14,761 for the nine months ended September 30, 2018 and 2017, respectively. The discrete benefits for the three months ended September 30, 2018 include $1,026 related to excess equity based compensation and $4,247 for return to provision adjustments. These were offset by discrete detriments for a U.S. tax rate adjustment of $2,195 related to profit in inventory from 2017 that flowed through to consolidated earnings in 2018 and $3,046 related to a valuation allowance primarily related to state tax credits. The discrete benefits for the nine months ended September 30, 2018 include $10,920 related to excess equity based compensation and $4,001 related to provision to return adjustments. These were offset by discrete detriments for the U.S. tax rate adjustment of 6,584 related to profit in inventory from 2017 that flowed through to consolidated earnings in 2018 and 3,046 related to a valuation allowance reflected primarily for state tax credits that exceed state income taxes in specific states. The discrete benefits in the three months ended September 30, 2017 include $3,738 related to excess equity based compensation and $2,111 related to provision to return related adjustments. The discrete benefits for the nine months ended September 30, 2017 include $10,883 related to excess equity based compensation, $2,240 related to the reversal of a tax reserve and $2,111 related to provision to return adjustments. In addition to the discrete items above, the effective tax rate for the three months ended September 30, 2018 benefited from certain tax adjustments made in accordance with SAB 118. SAB 118 provides guidance on accounting for the tax effects of the Tax Cuts and Jobs Act and allows a measurement period of up to one year from enactment to complete the accounting under ASC 740. The Company reduced its annual effective rate because of changes in the Global Intangible Low Taxed Income ("GILTI") tax calculation resulting from newly proposed regulations issued by the Treasury. The impact reduced the estimated tax expense for the nine months ended September 30, 2018 by $7,939, of which $4,747 had been reflected in tax expense as of June 30, 2018. The Company also finalized its calculation of the liability due to the deemed repatriation tax included in the Tax Act and recorded a $3,621 tax benefit which is included in the discrete benefit for provision to return adjustments detailed above. The Company accounts for its uncertain tax return reporting 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, 2018 and 2017: 2018 2017 Balance at January 1 $ 10,370 $ 6,403 Change in prior period positions (1,067) (2,240) Additions for tax positions in current period 1,012 1,500 Foreign currency translation (771) — Balance at September 30 $ 9,544 $ 5,663 Substantially all of the liability for uncertain tax benefits related to various federal, state and foreign income tax matters would benefit the Company's effective tax rate, if recognized. The Company is under tax audit in Germany (2013 - 2016) and Japan (2015 - 2017) and has been notified that a tax audit in Korea (2013 – 2017) will start later this year.

Net Income Attributable To IPG

Net Income Attributable To IPG Photonics Corporation Per Share	9 Months Ended
	Sep. 30, 2018
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, 2018 2017 2018 2017 Net income attributable to IPG Photonics Corporation $ 100,517 $ 115,597 $ 328,468 $ 294,658 Weighted average shares 53,571 53,440 53,677 53,453 Dilutive effect of common stock equivalents 1,125 1,258 1,318 1,117 Diluted weighted average common shares 54,696 54,698 54,995 54,570 Basic net income attributable to IPG Photonics Corporation per share $ 1.88 $ 2.16 $ 6.12 $ 5.51 Diluted net income attributable to IPG Photonics Corporation per share $ 1.84 $ 2.11 $ 5.97 $ 5.40 For the three months ended September 30, 2018 and 2017, respectively, the computation of diluted weighted average common shares excludes 20,400 and 8,800 common stock equivalents because the effect of including them would be anti-dilutive. The shares excluded for the three months ended September 30, 2018 and 2017, respectively are comprised of 10,500 and 3,800 restricted stock units ("RSUs") and 5,100 and 0 performance stock units ("PSUs"), and 4,800 and 5,000 non-qualified stock options, respectively. For the nine months ended September 30, 2018 and 2017, respectively, the computation of diluted weighted average common shares excludes 28,100 and 53,600 common stock equivalents because the effect of including them would be anti-dilutive.The shares excluded for the nine months ended September 30, 2018 and 2017, respectively, are comprised of 18,400 and 14,900 RSUs, 3,800 and 35,900 non-qualified stock options and 5,900 and 2,800 performance stock units. On July 31, 2018, the Company announced that its Board of Directors authorized a new $125 million anti-dilutive stock repurchase program following the completion of its previous $100 million repurchase program. Under the new anti-dilutive program, IPG management is authorized to repurchase shares of common stock in an amount not to exceed the greater of (a) the number of shares issued to employees and directors under the Company's various employee and director equity compensation and employee stock purchase plans from January 1, 2018 through March 31, 2019 and (b) $125 million, exclusive of any fees, commissions or other expenses. For the three months ended September 30, 2018 and 2017, the Company repurchased 371,228 shares and 17,328 shares of its common stock with an average price of $163.95 per share and $161.55 per share in the open market, respectively. The impact on the reduction of weighted average shares for the three months ended September 30, 2018 and 2017 was 119,911 shares and 9,964 shares, respectively. During the nine months ended September 30, 2018 and 2017, the Company repurchased a total of 585,806 shares and 215,860 shares of its common stock with an average price of $191.06 per share and $124.67 per share in the open market, respectively. The impact on the reduction of weighted average shares for the nine months ended September 30, 2018 and 2017 was 177,159 shares and 136,184 shares, respectively.

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements (Policies)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Basis of Presentation	Basis of Presentation — The accompanying unaudited 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 consolidated financial statements include the Company's accounts and those of its subsidiaries. All intercompany balances have been eliminated in consolidation. These 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, 2017.
Revenue Recognition	Revenue Recognition — Revenue is recognized when transfer of control to the customer occurs in an amount reflecting the consideration that the Company expects to be entitled. In order to achieve this core principle, the Company applies the following five step approach: (1) identify the contract with a customer, (2) identify the performance obligations in the contract, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations in the contract, and (5) recognize revenue when a performance obligation is satisfied. The Company considers customer purchase orders, which in some cases are governed by master sales agreements, to be the contracts with a customer. As part of its consideration of the contract, the Company evaluates certain factors including the customer's ability to pay (or credit risk). For each contract, the Company considers the promise to transfer products, each of which is distinct as the identified performance obligations. In determining the transaction price, the Company evaluates whether the price is subject to refund or adjustment to determine the net consideration to which the Company expects to be entitled. As the Company's standard payment terms are less than one year, the Company has elected the practical expedient under ASC 606-10-32-18 to not assess whether a contract has a significant financing component. The Company allocates the transaction price to each distinct product based on its relative standalone selling price. Revenue is recognized when control of the product is transferred to the customer (i.e., when the Company's performance obligation is satisfied), which typically occurs at shipment. The Company often receives orders with multiple delivery dates that may extend across several reporting periods. The Company allocates the transaction price of the contract to each delivery based on the product standalone selling price. The Company invoices for each scheduled delivery upon shipment and recognizes revenues for such delivery at that point, assuming transfer of control has occurred. As scheduled delivery dates are generally within 1 year, under the optional exemption provided by ASC 606-10-50-14 revenues allocated to future shipments of partially completed contracts are not disclosed. Rights of return generally are not included in customer contracts. Accordingly, upon application of steps one through five above, product revenue is recognized upon shipment and transfer of control. Returns are infrequent and are recorded as a reduction of revenue. In certain subsidiaries the Company provides sales commissions to sales representatives based on sales volume. The Company has determined that the incentive portion of its sales commissions qualify as contract costs. The Company has elected the practical expedient in ASC 340-40-25-4 to expense sales commissions when incurred as the amortization period of the asset that would otherwise have been recognized is one year or less. Revenue Recognition at a Point in Time — Revenues recognized at a point in time consist primarily of product, installation and service sales. The Company sells products to original equipment manufacturers ("OEMs") that supply materials processing laser systems, communications systems, medical laser systems and other laser systems for advanced applications to end users. The Company also sells products to end users that use IPG products directly to build their own systems, which incorporate IPG products or use IPG products as an energy or light source. The Company recognizes revenue for laser and spare part sales following the transfer of control of such products to the customer, which typically occurs upon shipment or delivery depending on the terms of the underlying contracts. Installation revenue is recognized upon completion of the installation service, which typically occurs within 90 days of delivery. For laser systems that carry customer specific processing requirements, revenue is recognized at the latter of customer acceptance date or shipment date if the customer acceptance is made prior to shipment. When sales contracts contain multiple performance obligations, such as the shipment or delivery of products and installation, the Company allocates the transaction price to each performance obligation identified in the contract based on relative standalone selling prices and recognizes the related revenue as control of each individual product or service is transferred to the customer, in satisfaction of the corresponding performance obligations. Revenue Recognition over Time — The Company offers extended warranty agreements, which extend the standard warranty periods. Warranties are limited and provide that the product meets specifications and is free from defects in materials and workmanship. Extended warranties are sold separately from products and represent a distinct performance obligation. Revenue related to the performance obligation for extended warranties is recognized over time as the customer simultaneously receives and consumes the benefits provided by the Company. The customer receives the assurance that the product will operate in accordance with agreed-upon specifications evenly during the extended warranty period regardless of whether they make a claim during that period, and therefore, revenue at time of sale is deferred and recognized over the time period of the extended warranty period. Customer Deposits and Deferred Revenue — When the Company receives consideration from a customer or such consideration is unconditionally due prior to transferring goods or services under the terms of a sales contract, the Company records customer deposits or deferred revenue, which represent contract liabilities. The Company recognizes 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.
Reclassifications	Reclassifications —
Recent Accounting Pronouncements	RECENT ACCOUNTING PRONOUNCEMENTS Adopted Pronouncements — On January 1, 2018, the Company adopted ASC 606 and all related amendments using the modified retrospective method for contracts that were not completed as of the date of initial application. The Company recognized the cumulative effect of initially applying the new revenue standard as an adjustment to the opening balance of retained earnings. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. The Company expects the impact of the adoption of the new standard to be immaterial to net income on an ongoing basis. A majority of revenue continues to be recognized at a point in time when control transfers based on the terms of underlying contact. Under the new revenue standard, the Company changed from deferring revenue for installation services in an amount equal to the greater of the cash received related to installation or the fair value to deferring the standalone selling price for these services. In February 2018, the FASB issued ASU No. 2018-02, "Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income" ("ASU 2018-02"). ASU 2018-02 allows a reclassification from accumulated other comprehensive income to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act ("the Act"). The Company adopted this standard during the first quarter of 2018, which resulted in the reclassification of $10 related to the tax effect of unrealized gains on derivatives. In October 2016, the FASB issued ASU No. 2016-16, "Income Taxes (Topic 740) - Intra-Entity Transfers of Assets other than Inventory" ("ASU 2016-16"). ASU 2016-16 eliminates the current exception that prohibits the recognition of current and deferred income tax consequences for intra-entity asset transfers (other than inventory) until the asset has been sold to an outside party. The amendments have been applied on a modified retrospective basis through a cumulative effect adjustment to retained earnings. The Company adopted this standard during the first quarter of 2018, which resulted in the reclassification of prepaid income taxes, deferred income taxes and retained earnings. The cumulative effect of the changes made to the Company's consolidated January 1, 2018 balance sheet for the adoption of ASC 606, ASU 2018-02 and ASU 2016-16 was as follows: Balance at Adoption of Adoption of Adoption of Balance at 12/31/2017 ASC 606 ASU 2018-02 ASU 2016-16 1/1/2018 Balance Sheet Prepaid income taxes $ 44,944 $ — $ — $ (1,203) $ 43,741 Deferred income tax assets 26,976 (55) — 1,229 28,150 Customer deposits and deferred revenue (short-term) 47,324 (816) — — 46,508 Income taxes payable 15,773 37 — — 15,810 Deferred income tax liabilities 21,362 134 — — 21,496 Retained earnings 1,443,867 590 (10) 26 1,444,473 Accumulated other comprehensive loss (77,344) — 10 — (77,334) In January 2017, the FASB issued ASU No. 2017-04, "Intangibles—Goodwill and Other (Topic 350)" ("ASU 2017-04"). ASU 2017-04 simplifies the accounting for goodwill impairments by eliminating step 2 from the goodwill impairment test. The amendments are applied prospectively upon adoption. The Company early adopted this standard during the first quarter of 2018. The Company performs its annual goodwill impairment assessment on October 1 of each year. The new impairment test will be used in the annual assessment or if events or changes in circumstances indicate that the carrying amount may not be recoverable and an impairment analysis is performed. Other Pronouncements Currently Under Evaluation — In February 2016, the FASB issued ASU No. 2016-02, "Leases (Topic 842)" ("ASU 2016-02" or "the new lease standard"). ASU 2016-02 requires a lessee to recognize assets and liabilities on the balance sheet for leases with lease terms greater than twelve months. ASU 2016-02 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018. In July 2018, the FASB issued ASU 2018-11, which provides an additional transition method for implementing the new lease standard. The Company will adopt the provisions of ASU 2018-11 by applying the standard at the adoption date and recognizing a cumulative-effect adjustment. The Company is currently completing its review of the lease population and is in the process of implementing a software solution to assist with lease accounting and evaluating footnote disclosures. The Company does not expect that the standard will have a material effect on its consolidated financial statements upon adoption. In June 2018, the FASB issued ASU No. 2018-07, "Compensation - Stock Compensation (Topic 718)" ("ASU 2018-07"). ASU 2018-07 aligns the accounting for share-based payments issued to employees and non-employees. ASU 2018-07 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2018, and early adoption is permitted. The Company is currently evaluating the standard but does not expect that it will have a material effect on its consolidated financial statements upon adoption.

Recent Accounting Pronounceme_3

Recent Accounting Pronouncements (Tables)	9 Months Ended
	Sep. 30, 2018
Accounting Policies [Abstract]
Cumulative Effect of Change to Balance Sheet	The cumulative effect of the changes made to the Company's consolidated January 1, 2018 balance sheet for the adoption of ASC 606, ASU 2018-02 and ASU 2016-16 was as follows: Balance at Adoption of Adoption of Adoption of Balance at 12/31/2017 ASC 606 ASU 2018-02 ASU 2016-16 1/1/2018 Balance Sheet Prepaid income taxes $ 44,944 $ — $ — $ (1,203) $ 43,741 Deferred income tax assets 26,976 (55) — 1,229 28,150 Customer deposits and deferred revenue (short-term) 47,324 (816) — — 46,508 Income taxes payable 15,773 37 — — 15,810 Deferred income tax liabilities 21,362 134 — — 21,496 Retained earnings 1,443,867 590 (10) 26 1,444,473 Accumulated other comprehensive loss (77,344) — 10 — (77,334)

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	9 Months Ended
	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables represent a disaggregation of revenue from contracts with customers for the three and nine months ended September 30, 2018: Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Sales by Application Materials processing $ 334,498 $ 1,065,712 Other applications 21,848 64,111 Total $ 356,346 $ 1,129,823 Three Months Ended September 30, 2018 Nine Months Ended September 30, 2018 Sales by Product High Power Continuous Wave ("CW") Lasers $ 227,462 $ 724,111 Medium Power CW Lasers 15,825 65,092 Low Power CW Lasers 3,276 10,380 Pulsed Lasers 35,408 115,243 Quasi-Continuous Wave ("QCW") Lasers 18,276 54,568 Other Revenue including Amplifiers, Laser Systems, Service, Parts, Accessories and Change in Deferred Revenue 56,099 160,429 Total $ 356,346 $ 1,129,823 Sales by Geography United States and other North America $ 53,762 $ 140,704 Europe: Germany 21,714 86,939 Other including Eastern Europe/CIS 66,392 225,717 Asia and Australia: China 158,853 511,852 Japan 21,871 60,927 Other 31,953 99,476 Rest of World 1,801 4,208 Total $ 356,346 $ 1,129,823 Timing of Revenue Recognition Goods and services transferred at a point in time $ 355,191 $ 1,126,285 Services transferred over time 1,155 3,538 Total $ 356,346 $ 1,129,823 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 is met. The Company bills customers for extended warranties upon entering into the agreement with the customer, resulting in deferred revenue. Revenue is recognized ratably over the term of the extended warranty agreement as the customer receives and consumes the benefits of such services.
Changes in Contract Liabilities	The following table reflects the changes in the Company's contract liabilities for the nine months ended September 30, 2018: September 30, January 1, 2018 2018 Change Contract liabilities Customer deposits $ 36,967 $ 36,937 $ 30 0.1 % Deferred revenue - current 11,307 9,571 1,736 18.1 % Deferred revenue - long-term 1,374 182 1,192 654.9 %
Schedule of Remaining Performance Obligations	The following table represents the Company's remaining performance obligations for sales of installation services and extended warranties and contracts with customer acceptance provisions included in deferred revenue as of September 30, 2018: Remaining Performance Obligations 2018 2019 2020 2021 2022 2023 Total Revenue expected to be recognized upon customer acceptance $ 7,443 $ 24 $ 3 $ — $ — $ — $ 7,470 Revenue expected to be recognized on contracts for installation services 246 236 — — — — 482 Revenue expected to be recognized for extended warranty agreements 1,165 1,910 576 349 178 60 4,238 Revenue deferred based on volume discount incentives — 491 — — — — 491 Total $ 8,854 $ 2,661 $ 579 $ 349 $ 178 $ 60 $ 12,681

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	9 Months Ended
	Sep. 30, 2018
Fair Value Disclosures [Abstract]
Assets And Liabilities Measured At Fair Value	The following table presents information about the Company's assets and liabilities measured at fair value: Fair Value Measurements at September 30, 2018 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 316,442 $ 316,442 $ — $ — U.S. Treasury and agency obligations 8,999 8,999 — — Commercial paper 89,312 — 89,312 — Short-term investments U.S. Treasury and agency obligations 113,094 113,094 — — Corporate bonds 196,856 196,856 — — Commercial paper 164,255 — 164,255 — Long-term investments and other assets: Corporate bonds 13,771 13,771 — — Auction rate securities 967 — — 967 Interest rate swap 13 — 13 — Total $ 903,709 $ 649,162 $ 253,580 $ 967 Liabilities Long-term debt $ 46,285 $ — $ 46,285 $ — Contingent purchase consideration 902 — — 902 Total $ 47,187 $ — $ 46,285 $ 902 Fair Value Measurements at December 31, 2017 Total Level 1 Level 2 Level 3 Assets Cash equivalents Money market fund deposits and term deposits $ 425,917 $ 425,917 $ — $ — Short-term investments U.S. Treasury and agency obligations 41,217 41,217 — — Corporate bonds 131,048 131,048 — — Commercial paper 33,896 33,896 — — Long-term investments and other assets: Auction rate securities 1,016 — — 1,016 Interest rate swaps 16 — 16 — Total $ 633,110 $ 632,078 $ 16 $ 1,016 Liabilities Long-term debt $ 48,982 $ — $ 48,982 $ — Contingent purchase consideration 902 — — 902 Total $ 49,884 $ — $ 48,982 $ 902
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, 2018 2017 2018 2017 Auction rate securities Balance, beginning of period $ 1,174 $ 1,148 $ 1,016 $ 1,144 Period transactions (207) (138) (207) (138) Change in fair value and accretion — 2 158 6 Balance, end of period $ 967 $ 1,012 $ 967 $ 1,012 Contingent purchase consideration Balance, beginning of period $ 902 $ — $ 902 $ — Balance, end of period $ 902 $ — $ 902 $ —
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, 2018 2017 2018 2017 Auction rate securities Balance, beginning of period $ 1,174 $ 1,148 $ 1,016 $ 1,144 Period transactions (207) (138) (207) (138) Change in fair value and accretion — 2 158 6 Balance, end of period $ 967 $ 1,012 $ 967 $ 1,012 Contingent purchase consideration Balance, beginning of period $ 902 $ — $ 902 $ — Balance, end of period $ 902 $ — $ 902 $ —
Schedule of Effective Maturity Dates of Held To Maturity Investments	The following table presents the effective maturity dates of held-to-maturity debt investments as of September 30, 2018 and December 31, 2017: September 30, 2018 December 31, 2017 Book Value Fair Value Book Value Fair Value Investment maturity Less than 1 year $ 572,815 $ 572,516 $ 206,161 $ 206,161 1 through 5 years 13,776 13,771 — — Greater than 5 years 844 967 1,016 1,016 Total $ 587,435 $ 587,254 $ 207,177 $ 207,177

Inventories (Tables)

Inventories (Tables)	9 Months Ended
	Sep. 30, 2018
Inventory Disclosure [Abstract]
Components of Inventories	Inventories consist of the following: September 30, December 31, 2018 2017 Components and raw materials $ 240,635 $ 145,261 Work-in-process 40,763 43,646 Finished components and devices 116,011 118,805 Total $ 397,409 $ 307,712

Goodwill And Intangibles (Table

Goodwill And Intangibles (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table sets forth the changes in the carrying amount of goodwill for the nine months ended September 30, 2018: Amounts Balance at January 1 $ 55,831 Goodwill arising from acquisition 4,072 Adjustment to goodwill during measurement period (2,948) Foreign exchange adjustment (186) Balance at September 30 $ 56,769
Schedule of Intangible Assets	Intangible assets, subject to amortization, consisted of the following: September 30, 2018 December 31, 2017 Gross Carrying Accumulated Net Carrying Weighted- Average Lives Gross Carrying Accumulated Net Carrying Weighted- Patents $ 8,036 $ (5,893) $ 2,143 8 Years $ 8,036 $ (5,486) $ 2,550 8 Years Customer relationships 25,577 (5,603) 19,974 11 Years 26,768 (5,584) 21,184 11 Years Production know-how 6,768 (5,595) 1,173 8 Years 6,820 (5,035) 1,785 8 Years Technology, trademark and trade names 32,358 (9,804) 22,554 7 Years 32,564 (6,860) 25,704 8 Years Total $ 72,739 $ (26,895) $ 45,844 $ 74,188 $ (22,965) $ 51,223
Estimated Future Amortization Expense For Intangibles	The estimated future amortization expense for intangibles for the remainder of 2018 and subsequent years is as follows: 2018 2019 2020 2021 2022 Thereafter Total $ 1,870 $ 7,400 $ 6,747 $ 6,574 $ 5,775 $ 17,478 $ 45,844

Accrued Expenses And Other Li_2

Accrued Expenses And Other Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Payables and Accruals [Abstract]
Components of Accrued Expenses and Other Liabilities	Accrued expenses and other liabilities consist of the following: September 30, December 31, 2018 2017 Accrued compensation $ 57,037 $ 63,203 Customer deposits and deferred revenue 48,274 47,324 Current portion of accrued warranty 22,045 25,059 Other 9,704 8,831 Total $ 137,060 $ 144,417

Product Warranties (Tables)

Product Warranties (Tables)	9 Months Ended
	Sep. 30, 2018
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, 2018 and 2017. 2018 2017 Balance at January 1 $ 47,517 $ 33,978 Provision for warranty accrual 19,050 20,284 Warranty claims (13,827) (11,746) Foreign currency translation (1,057) 2,459 Balance at September 30 $ 51,683 $ 44,975

Financing Arrangements (Tables)

Financing Arrangements (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Borrowings Under Existing Financing Arrangements	The Company's borrowings under existing financing arrangements consist of the following: September 30, December 31, 2018 2017 Long-term notes 46,285 48,982 Less: current portion (3,654) (3,604) Total long-term debt $ 42,631 $ 45,378

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	9 Months Ended
	Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives	The fair value amounts in the consolidated balance sheets were: Notional Amounts 1 Other Assets Other Current Liabilities September 30, December 31, September 30, December 31, September 30, December 31, 2018 2017 2018 2017 2018 2017 Derivative designated as a cash flow hedge: Interest rate swap $ 21,078 $ 21,969 $ 13 $ 16 $ — $ — (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	Gains associated with derivative instruments not designated as hedging instruments are as follows: Three Months Ended September 30, Nine Months Ended September 30, Classification 2018 2017 2018 2017 Gain (loss) recognized in income Gain (loss) on foreign exchange $ 1,169 $ — $ (19) $ — The following table reflects the effect of the interest rate swap contract designated as a cash flow hedging instrument in the Company's financial statements: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Effective portion recognized in other comprehensive income, pretax: Interest rate swap $ (5) $ (7) $ (3) $ (47)

Income Taxes (Tables)

Income Taxes (Tables)	9 Months Ended
	Sep. 30, 2018
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, 2018 and 2017: 2018 2017 Balance at January 1 $ 10,370 $ 6,403 Change in prior period positions (1,067) (2,240) Additions for tax positions in current period 1,012 1,500 Foreign currency translation (771) — Balance at September 30 $ 9,544 $ 5,663

Net Income Attributable To IP_2

Net Income Attributable To IPG Photonics Corporation Per Share (Tables)	9 Months Ended
	Sep. 30, 2018
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, 2018 2017 2018 2017 Net income attributable to IPG Photonics Corporation $ 100,517 $ 115,597 $ 328,468 $ 294,658 Weighted average shares 53,571 53,440 53,677 53,453 Dilutive effect of common stock equivalents 1,125 1,258 1,318 1,117 Diluted weighted average common shares 54,696 54,698 54,995 54,570 Basic net income attributable to IPG Photonics Corporation per share $ 1.88 $ 2.16 $ 6.12 $ 5.51 Diluted net income attributable to IPG Photonics Corporation per share $ 1.84 $ 2.11 $ 5.97 $ 5.40

Basis Of Presentation And Sig_2

Basis Of Presentation And Significant Accounting Policies (Narrative) (Details)	9 Months Ended
	Sep. 30, 2018
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Scheduled delivery dates, period (within)	1 year
Installation services, completion period	90 days

Recent Accounting Pronounceme_4

Recent Accounting Pronouncements (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)
ASU 2018-02 | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Reclassification from AOCI to retained earnings, Tax Cuts and Jobs Act of 2017	$ 10

Recent Accounting Pronounceme_5

Recent Accounting Pronouncements (Cumulative Effect of Change to Balance Sheet) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid income taxes	$ 61,222	$ 43,741	$ 44,944
Deferred income tax assets	19,995	28,150	26,976
Customer deposits and deferred revenue (short-term)		46,508
Income taxes payable	47,777	15,810	15,773
Deferred income tax liabilities		21,496
Retained earnings	1,772,941	1,444,473	1,443,867
Accumulated other comprehensive loss	$ (144,409)	(77,334)	(77,344)
Before Adoption of Standard
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid income taxes			44,944
Deferred income tax assets			26,976
Customer deposits and deferred revenue (short-term)			47,324
Income taxes payable			15,773
Deferred income tax liabilities			21,362
Retained earnings			1,443,867
Accumulated other comprehensive loss			$ (77,344)
Adoption of Standard | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Deferred income tax assets		(55)
Customer deposits and deferred revenue (short-term)		(816)
Income taxes payable		37
Deferred income tax liabilities		134
Retained earnings		590
Adoption of Standard | ASU 2018-02
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings		(10)
Accumulated other comprehensive loss		10
Adoption of Standard | ASU 2016-16
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid income taxes		(1,203)
Deferred income tax assets		1,229
Retained earnings		$ 26

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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Sales by Application
Total	$ 356,346	$ 392,615	$ 1,129,823	$ 1,047,834
Materials processing
Sales by Application
Total	334,498		1,065,712
Other applications
Sales by Application
Total	$ 21,848		$ 64,111

Revenue From Contract With Cust

Revenue From Contract With Customers (Disaggregation of Revenue, By Product) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total	$ 356,346	$ 392,615	$ 1,129,823	$ 1,047,834
High Power Continuous Wave ("CW") Lasers
Disaggregation of Revenue [Line Items]
Total	227,462		724,111
Medium Power CW Lasers
Disaggregation of Revenue [Line Items]
Total	15,825		65,092
Low Power CW Lasers
Disaggregation of Revenue [Line Items]
Total	3,276		10,380
Pulsed Lasers
Disaggregation of Revenue [Line Items]
Total	35,408		115,243
Quasi-Continuous Wave ("QCW") Lasers
Disaggregation of Revenue [Line Items]
Total	18,276		54,568
Other Revenue including Amplifiers, Laser Systems, Service, Parts, Accessories and Change in Deferred Revenue
Disaggregation of Revenue [Line Items]
Total	$ 56,099		$ 160,429

Revenue From Contracts With C_4

Revenue From Contracts With Customers (Disaggregation of Revenue, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Sales by Geography
Total	$ 356,346	$ 392,615	$ 1,129,823	$ 1,047,834
United States and other North America
Sales by Geography
Total	53,762		140,704
Germany
Sales by Geography
Total	21,714		86,939
Other including Eastern Europe/CIS
Sales by Geography
Total	66,392		225,717
China
Sales by Geography
Total	158,853		511,852
Japan
Sales by Geography
Total	21,871		60,927
Other
Sales by Geography
Total	31,953		99,476
Rest of World
Sales by Geography
Total	$ 1,801		$ 4,208

Revenue From Contracts With C_5

Revenue From Contracts With Customers (Disaggregation of Revenue, By Timing) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Timing of Revenue Recognition
Total	$ 356,346	$ 392,615	$ 1,129,823	$ 1,047,834
Goods and services transferred at a point in time
Timing of Revenue Recognition
Total	355,191		1,126,285
Services transferred over time
Timing of Revenue Recognition
Total	$ 1,155		$ 3,538

Revenue From Contracts With C_6

Revenue From Contracts With Customers (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Decrease in revenue recognized	$ (356,346)	$ (392,615)	$ (1,129,823)	$ (1,047,834)
Revenue recognized that was included in the contract liability balance at the beginning of the period	3,355		38,885
Difference between Revenue Guidance in Effect before and after Topic 606 | ASC 606
Disaggregation of Revenue [Line Items]
Decrease in revenue recognized	$ 37		$ 84

Revenue From Contracts With C_7

Revenue From Contracts With Customers (Changes in Contract Assets and Contract Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jan. 01, 2018
Contract liabilities
Customer deposits - current	$ 36,967
Deferred revenue - current	11,307
Deferred revenue - long-term	$ 1,374
Calculated under Revenue Guidance in Effect before Topic 606
Contract liabilities
Customer deposits - current		$ 36,937
Deferred revenue - current		9,571
Deferred revenue - long-term		182
Difference between Revenue Guidance in Effect before and after Topic 606 | ASC 606
Contract liabilities
Customer deposits - current		$ 30
Customer deposits, Change		0.10%
Deferred revenue - current		$ 1,736
Deferred revenue - current, Change		18.10%
Deferred revenue - long-term		$ 1,192
Deferred revenue - long-term, Change		654.90%

Revenue From Contracts With C_8

Revenue From Contracts With Customer (Schedule of Remaining Performance Obligations) (Details) $ in Thousands	Sep. 30, 2018USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 8,854
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01 | Revenue expected to be recognized upon customer acceptance
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 7,443
Remaining Performance Obligations, Expected Timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01 | Revenue expected to be recognized on contracts for installation services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 246
Remaining Performance Obligations, Expected Timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 1,165
Remaining Performance Obligations, Expected Timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01 | Revenue deferred based on volume discount incentives
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 0
Remaining Performance Obligations, Expected Timing	3 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 2,661
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 | Revenue expected to be recognized upon customer acceptance
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 24
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 | Revenue expected to be recognized on contracts for installation services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 236
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 1,910
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01 | Revenue deferred based on volume discount incentives
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 491
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 579
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | Revenue expected to be recognized upon customer acceptance
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 3
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | Revenue expected to be recognized on contracts for installation services
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]: 2020-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 576
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | Revenue deferred based on volume discount incentives
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]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 349
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Revenue expected to be recognized upon customer acceptance
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]: 2021-01-01 | Revenue expected to be recognized on contracts for installation services
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]: 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	$ 349
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Revenue deferred based on volume discount incentives
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]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 178
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Revenue expected to be recognized upon customer acceptance
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]: 2022-01-01 | Revenue expected to be recognized on contracts for installation services
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]: 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	$ 178
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Revenue deferred based on volume discount incentives
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	$ 60
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Revenue expected to be recognized upon customer acceptance
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 expected to be recognized on contracts for installation services
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 expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 60
Remaining Performance Obligations, Expected Timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Revenue deferred based on volume discount incentives
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]: (nil)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 12,681
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil) | Revenue expected to be recognized upon customer acceptance
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	7,470
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil) | Revenue expected to be recognized on contracts for installation services
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	482
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil) | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	4,238
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: (nil) | Revenue deferred based on volume discount incentives
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining Performance Obligations	$ 491

Fair Value Measurements (Assets

Fair Value Measurements (Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Assets
Total	$ 903,709	$ 633,110
Liabilities
Long-term debt	46,285	48,982
Contingent purchase consideration	902	902
Total	47,187	49,884
Level 1
Assets
Total	649,162	632,078
Liabilities
Long-term debt	0	0
Contingent purchase consideration	0	0
Total	0	0
Level 2
Assets
Total	253,580	16
Liabilities
Long-term debt	46,285	48,982
Contingent purchase consideration	0	0
Total	46,285	48,982
Level 3
Assets
Total	967	1,016
Liabilities
Long-term debt	0	0
Contingent purchase consideration	902	902
Total	902	902
Money market fund deposits and term deposits
Assets
Cash equivalents	316,442	425,917
Money market fund deposits and term deposits | Level 1
Assets
Cash equivalents	316,442	425,917
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
U.S. Treasury and agency obligations
Assets
Cash equivalents	8,999
Short-term investments	113,094	41,217
U.S. Treasury and agency obligations | Level 1
Assets
Cash equivalents	8,999
Short-term investments	113,094	41,217
U.S. Treasury and agency obligations | Level 2
Assets
Cash equivalents	0
Short-term investments	0	0
U.S. Treasury and agency obligations | Level 3
Assets
Cash equivalents	0
Short-term investments	0	0
Commercial paper
Assets
Cash equivalents	89,312
Commercial paper | Level 1
Assets
Cash equivalents	0
Commercial paper | Level 2
Assets
Cash equivalents	89,312
Commercial paper | Level 3
Assets
Cash equivalents	0
Corporate bonds
Assets
Short-term investments	196,856	131,048
Long-term investments and other assets	13,771
Corporate bonds | Level 1
Assets
Short-term investments	196,856	131,048
Long-term investments and other assets	13,771
Corporate bonds | Level 2
Assets
Short-term investments	0	0
Long-term investments and other assets	0
Corporate bonds | Level 3
Assets
Short-term investments	0	0
Long-term investments and other assets	0
Commercial paper, not included in cash equivalents
Assets
Short-term investments	164,255	33,896
Commercial paper, not included in cash equivalents | Level 1
Assets
Short-term investments	0	33,896
Commercial paper, not included in cash equivalents | Level 2
Assets
Short-term investments	164,255	0
Commercial paper, not included in cash equivalents | Level 3
Assets
Short-term investments	0	0
Auction rate securities
Assets
Long-term investments and other assets	967	1,016
Auction rate securities | Level 1
Assets
Long-term investments and other assets	0	0
Auction rate securities | Level 2
Assets
Long-term investments and other assets	0	0
Auction rate securities | Level 3
Assets
Long-term investments and other assets	967	1,016
Interest rate swap
Assets
Long-term investments and other assets	13	16
Interest rate swap | Level 1
Assets
Long-term investments and other assets	0	0
Interest rate swap | Level 2
Assets
Long-term investments and other assets	13	16
Interest rate swap | Level 3
Assets
Long-term investments and other assets	$ 0	$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets. fair value	$ 903,709	$ 633,110
Book value	28,043	19,009
Held-to-maturity Securities | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets. fair value	474,205	206,161
Unrealized gain (loss)	(217)	$ (96)
Held-to-maturity Securities | Long-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets. fair value	14,738
Unrealized gain (loss)	118
Book value	$ 14,620

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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	$ 1,174	$ 1,148	$ 1,016	$ 1,144
Period transactions	(207)	(138)	(207)	(138)
Change in fair value and accretion	0	2	158	6
Balance, end of period	967	1,012	967	1,012
Contingent purchase consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	902	0	902	0
Balance, end of period	$ 902	$ 0	$ 902	$ 0

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Effective Maturity Dates of Held To Maturity Investments) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Investment maturity
Held-to-maturity Debt Maturities, Less than 1 year, Book Value	$ 572,815	$ 206,161
Held-to-maturity Debt Maturities, 1 through 5 years, Book Value	13,776	0
Held-to-maturity Debt Maturities, Greater than 5 years, Book Value	844	1,016
Held-to-maturity Debt Maturities, Total Book Value	587,435	207,177
Held-to-maturity Debt Maturities, Less than 1 year, Fair Value	572,516	206,161
Held-to-maturity Debt Maturities, 1 through 5 years, Fair Value	13,771	0
Held-to-maturity Debt Maturities, Greater than 5 years, Fair Value	967	1,016
Held-to-maturity Debt Maturities, Total Fair Value	$ 587,254	$ 207,177

Inventories (Components Of Inve

Inventories (Components Of Inventories) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Components and raw materials	$ 240,635	$ 145,261
Work-in-process	40,763	43,646
Finished components and devices	116,011	118,805
Total	$ 397,409	$ 307,712

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Inventory Disclosure [Abstract]
Inventory provisions	$ 3,076	$ 4,033	$ 9,930	$ 13,439

Goodwill And Intangibles (Sched

Goodwill And Intangibles (Schedule of Changes) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)
Goodwill [Roll Forward]
Balance at January 1	$ 55,831
Goodwill arising from acquisition	4,072
Adjustment to goodwill during measurement period	(2,948)
Foreign exchange adjustment	(186)
Balance at September 30	$ 56,769

Goodwill And Intangibles (Intan

Goodwill And Intangibles (Intangible Assets) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 72,739	$ 74,188
Accumulated Amortization	(26,895)	(22,965)
Net Carrying Amount	45,844	51,223
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	8,036	8,036
Accumulated Amortization	(5,893)	(5,486)
Net Carrying Amount	$ 2,143	$ 2,550
Weighted- Average Lives	8 years	8 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 25,577	$ 26,768
Accumulated Amortization	(5,603)	(5,584)
Net Carrying Amount	$ 19,974	$ 21,184
Weighted- Average Lives	11 years	11 years
Production know-how
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 6,768	$ 6,820
Accumulated Amortization	(5,595)	(5,035)
Net Carrying Amount	$ 1,173	$ 1,785
Weighted- Average Lives	8 years	8 years
Technology, trademark and trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 32,358	$ 32,564
Accumulated Amortization	(9,804)	(6,860)
Net Carrying Amount	$ 22,554	$ 25,704
Weighted- Average Lives	7 years	8 years

Goodwill And Intangibles (Narra

Goodwill And Intangibles (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2018	Jun. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Goodwill arising from acquisition				$ 4,072
Amortization expense	$ 1,982		$ 1,725	$ 5,821	$ 3,958
RC
Business Acquisition [Line Items]
Percentage of business acquired		100.00%
Purchase price		$ 4,453
Goodwill arising from acquisition		4,072
Trademarks and Trade Names | RC
Business Acquisition [Line Items]
Acquired finite-lived intangible assets		104
Weighted average useful life of acquired intangible assets				1 year
Customer relationships | RC
Business Acquisition [Line Items]
Acquired finite-lived intangible assets		$ 557
Weighted average useful life of acquired intangible assets				10 years

Goodwill And Intangibles (Estim

Goodwill And Intangibles (Estimated Future Amortization Expense For Intangibles) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
2,018	$ 1,870
2,019	7,400
2,020	6,747
2,021	6,574
2,022	5,775
Thereafter	17,478
Net Carrying Amount	$ 45,844	$ 51,223

Accrued Expenses And Other Li_3

Accrued Expenses And Other Liabilities (Components Of Accrued Expenses And Other Liabilities) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued compensation	$ 57,037	$ 63,203
Customer deposits and deferred revenue	48,274	47,324
Current portion of accrued warranty	22,045	25,059
Other	9,704	8,831
Total	$ 137,060	$ 144,417

Product Warranties (Narrative)

Product Warranties (Narrative) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Product Warranty Liability [Line Items]
Accrued warranty reported in accrued expenses and other liabilities	$ 22,045	$ 25,059
Accrued warranty reported in other long-term liabilities	$ 29,638	$ 22,458
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	3 years

Product Warranties (Summary Of

Product Warranties (Summary Of Product Warranty Activity) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Movement in Standard and Extended Product Warranty, Increase (Decrease) [Roll Forward]
Balance at January 1	$ 47,517	$ 33,978
Provision for warranty accrual	19,050	20,284
Warranty claims	(13,827)	(11,746)
Foreign currency translation	(1,057)	2,459
Balance at September 30	$ 51,683	$ 44,975

Financing Arrangements (Borrowi

Financing Arrangements (Borrowings Under Existing Financing Arrangements) (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Long-term notes	$ 42,631	$ 45,378
Less: current portion	(3,654)	(3,604)
Total long-term debt	42,631	45,378
Long-term notes
Debt Instrument [Line Items]
Long-term notes	$ 46,285	$ 48,982

Financing Arrangements (Narrati

Financing Arrangements (Narrative) (Details) € in Thousands	9 Months Ended
	Sep. 30, 2018USD ($)	May 31, 2023USD ($)	Jul. 31, 2022USD ($)	Sep. 30, 2018EUR (€)	Dec. 31, 2017USD ($)
Debt Instrument [Line Items]
Total unused credit lines and overdraft facilities	$ 108,152,000
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	2.90%			2.90%
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	$ 25,207,000
Current portion of long-term note	$ 2,466,000
Fixed interest rate swap	2.70%			2.70%
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	$ 21,078,000
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	955,000				520,000
Euro line-of-credit
Debt Instrument [Line Items]
Line of credit	0				0
Guarantees issued	1,222,000				$ 798,000
Euro overdraft facility
Debt Instrument [Line Items]
Line of credit	0
Letter of Credit | U.S. line-of-credit
Debt Instrument [Line Items]
Borrowing capacity	50,000,000
Letter of Credit | Euro line-of-credit
Debt Instrument [Line Items]
Borrowing capacity	58,009,000			€ 50,000
Letter of Credit | Euro overdraft facility
Debt Instrument [Line Items]
Borrowing capacity	$ 2,320,000			€ 2,000

Derivative Financial Instrume_3

Derivative Financial Instruments (Fair Value) (Details) - Derivative designated as a cash flow hedge - Interest rate swap - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivatives, Fair Value [Line Items]
Notional Amounts	$ 21,078,000	$ 21,969,000
Other Assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	13,000	16,000
Other Current Liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, fair value	$ 0	$ 0

Derivative Financial Instrume_4

Derivative Financial Instruments (Derivative Gains (Losses) In The Consolidated Statements Of Income Related To Interest Rate Swap Contracts) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Foreign currency forward contracts
Derivative Instruments, Gain (Loss) [Line Items]
Loss recognized in income	$ 1,169	$ 0	$ (19)	$ 0
Derivative designated as a cash flow hedge | Interest rate swap
Derivative Instruments, Gain (Loss) [Line Items]
Effective portion recognized in other comprehensive income, pretax	$ (5)	$ (7)	$ (3)	$ (47)

Commitments And Contingencies (

Commitments And Contingencies (Narrative) (Details)	Sep. 30, 2018USD ($)
Commitments and Contingencies Disclosure [Abstract]
Legal proceedings	$ 0

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	21.40%	28.00%		24.20%	27.00%
Discrete tax benefit	$ 660	$ 5,714		$ 5,178	$ 14,761
Discrete tax benefit, equity based compensation	1,026	3,738		10,920	10,883
Discrete tax benefit, provision adjustment	(4,247)	$ 2,111		4,001	2,111
Discrete tax rate adjustment, inventory	2,195			6,584
Discrete tax rate adjustment, valuation allowance	$ 3,046			3,046
Discrete tax benefit, reversal of tax reserve					$ 2,240
Decrease in income taxes				7,939
Tax Cuts and Jobs Act of 2017, income tax expense			$ 4,747
Tax benefit				$ 3,621

Income Taxes (Schedule of Unrec

Income Taxes (Schedule of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 10,370	$ 6,403
Change in prior period positions	(1,067)	(2,240)
Additions for tax positions in current period	1,012	1,500
Foreign currency translation	(771)	0
Balance at September 30	$ 9,544	$ 5,663

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, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income attributable to IPG Photonics Corporation	$ 100,517	$ 115,597	$ 328,468	$ 294,658
Weighted average shares (in shares)	53,571	53,440	53,677	53,453
Dilutive effect of common stock equivalents (in shares)	1,125	1,258	1,318	1,117
Diluted weighted average common shares (in shares)	54,696	54,698	54,995	54,570
Basic net income attributable to IPG Photonics Corporation per share (in dollars per share)	$ 1.88	$ 2.16	$ 6.12	$ 5.51
Diluted net income attributable to IPG Photonics Corporation per share (in dollars per share)	$ 1.84	$ 2.11	$ 5.97	$ 5.40

Net Income Attributable to IP_4

Net Income Attributable to IPG Photonics Corporation Per Share (Narrative) (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jul. 31, 2018	Jul. 30, 2018
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Excluded from computation of diluted weighted average common shares (in shares)	20,400	8,800	28,100	53,600
Share repurchase amount (no more than)					$ 125	$ 100
Stock repurchased during period (in shares)	371,228	17,328	585,806	215,860
Stock repurchase average price (in dollars per share)	$ 163.95	$ 161.55	$ 191.06	$ 124.67
Decrease in weighted average shares outstanding, treasury stock (in shares)	119,911	9,964	177,159	136,184
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)	10,500	3,800	18,400	14,900
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)	5,100	0	5,900	2,800
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)	4,800	5,000	3,800	35,900