IPG Photonics (IPGP) 10-K 24 Feb 20 2019 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Jun. 30, 2019
Cover page.
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	001-33155
Entity Registrant Name	IPG PHOTONICS CORP
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	04-3444218
Entity Address, Address Line One	50 Old Webster Road
Entity Address, City or Town	Oxford
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	01540
City Area Code	508
Local Phone Number	373-1100
Title of 12(b) Security	Common Stock, Par Value $0.0001 per share
Trading Symbol	IPGP
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 5.1
Entity Common Stock, Shares Outstanding		53,058,726
Documents Incorporated by Reference	Portions of the registrant's Proxy Statement for its 2020 Annual Meeting of Stockholders to be filed pursuant to Regulation 14A within 120 days of the end of the registrant's fiscal year ended December 31, 2019 are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein.
Amendment Flag	false
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2019
Entity Central Index Key	0001111928
Current Fiscal Year End Date	--12-31

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 680,070	$ 544,358
Short-term investments	502,546	500,432
Accounts receivable, net	238,479	255,509
Inventories	380,790	403,579
Prepaid income taxes	38,873	43,782
Prepaid expenses and other current assets	55,876	57,764
Total current assets	1,896,634	1,805,424
Deferred income taxes, net	31,395	19,165
Goodwill	82,092	100,722
Intangible assets, net	74,271	87,139
Property, plant and equipment, net	600,852	543,068
Other assets	45,192	18,932
Total assets	2,730,436	2,574,450
Current liabilities:
Current portion of long-term debt	3,740	3,671
Accounts payable	27,329	36,302
Accrued expenses and other liabilities	149,782	154,640
Income taxes payable	11,053	51,161
Total current liabilities	191,904	245,774
Deferred income taxes and other long-term liabilities	98,121	80,734
Long-term debt, net of current portion	37,968	41,707
Total liabilities	327,993	368,215
Commitments and contingencies (Note 14)
IPG Photonics Corporation equity:
Common stock, $0.0001 par value, 175,000,000 shares authorized; 54,743,227 and 53,010,875 shares issued and outstanding, respectively, at December 31, 2019; 54,371,701 and 52,941,607 shares issued and outstanding, respectively, at December 31, 2018.	5	5
Treasury stock, at cost, 1,732,352 and 1,430,094 shares held at December 31, 2019 and December 31, 2018, respectively.	(265,730)	(224,998)
Additional paid-in capital	785,636	744,937
Retained earnings	2,028,734	1,848,500
Accumulated other comprehensive loss	(146,919)	(162,896)
Total IPG Photonics Corporation stockholders' equity	2,401,726	2,205,548
Non-controlling interests	717	687
Total equity	2,402,443	2,206,235
Total liabilities and equity	$ 2,730,436	$ 2,574,450

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2019	Dec. 31, 2018
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)	54,743,227	54,371,701
Common stock, shares outstanding (in shares)	53,010,875	52,941,607
Treasury stock, shares (in shares)	1,732,352	1,430,094

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Net sales	$ 1,314,581	$ 1,459,874	$ 1,408,889
Cost of sales	708,372	659,606	611,978
Gross profit	606,209	800,268	796,911
Operating expenses:
Sales and marketing	77,745	57,815	49,801
Research and development	129,997	122,769	100,870
General and administrative	107,597	102,429	80,668
Goodwill impairment	37,120	0	0
Impairment of long-lived assets and other restructuring charges	7,130	0	0
Loss (gain) on foreign exchange	12,827	(6,150)	14,460
Total operating expenses	372,416	276,863	245,799
Operating income	233,793	523,405	551,112
Other income, net:
Interest income, net	14,238	9,057	737
Other income, net	345	1,933	22
Total other income	14,583	10,990	759
Income before provision for income taxes	248,376	534,395	551,871
Provision for income taxes	68,115	130,226	204,283
Net income	180,261	404,169	347,588
Less: net income (loss) attributable to non-controlling interests	27	142	(26)
Net income attributable to IPG Photonics Corporation	$ 180,234	$ 404,027	$ 347,614
Net income attributable to IPG Photonics Corporation per share:
Basic (in dollars per share)	$ 3.40	$ 7.55	$ 6.50
Diluted (in dollars per share)	$ 3.35	$ 7.38	$ 6.36
Weighted average shares outstanding:
Basic (in shares)	53,061	53,522	53,495
Diluted (in shares)	53,839	54,726	54,699

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 180,261	$ 404,169	$ 347,588
Other comprehensive income (loss), net of tax:
Foreign currency translation adjustments	15,997	(85,590)	101,056
Foreign currency translation adjustments			100,999
Unrealized (loss) gain on derivatives	(17)	15
Unrealized gain (loss) on derivatives			(58)
Effect of adopted accounting standards	0	10	0
Unrealized loss on available-for-sale investments, net of tax	0	0	(240)
Loss on available-for-sale investments, net of tax reclassified to net income	0	0	538
Total other comprehensive income (loss)	15,980	(85,565)	101,239
Comprehensive income	196,241	318,604	448,827
Comprehensive gain attributable to non-controlling interest	30	129	31
Comprehensive income attributable to IPG Photonics Corporation	$ 196,211	$ 318,475	$ 448,796

Consolidated Statements Of Equi

Consolidated Statements Of Equity - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive (Loss) Income	Non- controlling Interest
Beginning balance (in shares) at Dec. 31, 2016		53,251,805	102,774
Beginning balance at Dec. 31, 2016	$ 1,557,724	$ 5	$ (8,946)	$ 650,974	$ 1,094,108	$ (178,583)	$ 166
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of RSU's and PSU's (in shares)		617,662
Exercise of stock options and vesting of RSU's and PSU's	25,062			25,062
Common stock issued under employee stock purchase plan (in shares)		35,467
Common stock issued under employee stock purchase plan	3,592			3,592
Purchased common stock (in shares)		(275,495)	(275,495)
Purchased common stock	(39,987)		$ (39,987)
Stock-based compensation	23,021			23,021
Purchase of non-controlling interest	(197)						(197)
Net income	347,588				347,614		(26)
Foreign currency translation adjustments	101,056					100,999	57
Unrealized gain on derivatives, net of tax	(58)					(58)
Unrealized loss on available-for-sale investments, net of tax	(240)					(240)
Unrealized loss on available-for-sale investments, net of tax	538					538
Ending balance (in shares) at Dec. 31, 2017		53,629,439	378,269
Ending balance 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 vesting of RSU's and PSU's (in shares)		351,795
Exercise of stock options and vesting of RSU's and PSU's	9,895			9,895
Common stock issued under employee stock purchase plan (in shares)		12,198
Common stock issued under employee stock purchase plan	2,288			2,288
Purchased common stock (in shares)		(1,051,825)	(1,051,825)
Purchased common stock	(176,065)		$ (176,065)
Stock-based compensation	28,027			28,027
Purchase of non-controlling interest	558						558
Net income	404,169				404,027		142
Foreign currency translation adjustments	(85,590)					(85,577)	(13)
Unrealized loss on available-for-sale investments, net of tax	0
Unrealized loss on available-for-sale investments, net of tax	0
Unrealized loss on derivatives, net of tax	15					15
Ending balance (in shares) at Dec. 31, 2018		52,941,607	1,430,094
Ending balance at Dec. 31, 2018	2,206,235	$ 5	$ (224,998)	744,937	1,848,500	(162,896)	687
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options and vesting of RSU's and PSU's (in shares)		319,211
Exercise of stock options and vesting of RSU's and PSU's	805			805
Common stock issued under employee stock purchase plan (in shares)		52,315
Common stock issued under employee stock purchase plan	6,531			6,531
Purchased common stock (in shares)		(302,258)	(302,258)
Purchased common stock	(40,732)		$ (40,732)
Stock-based compensation	33,363			33,363
Net income	180,261				180,234		27
Foreign currency translation adjustments	15,997					15,994	3
Unrealized loss on available-for-sale investments, net of tax	0
Unrealized loss on available-for-sale investments, net of tax	0
Unrealized loss on derivatives, net of tax	(17)					(17)
Ending balance (in shares) at Dec. 31, 2019		53,010,875	1,732,352
Ending balance at Dec. 31, 2019	$ 2,402,443	$ 5	$ (265,730)	$ 785,636	$ 2,028,734	$ (146,919)	$ 717

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income	$ 180,261	$ 404,169	$ 347,588
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	96,268	80,271	64,568
Deferred income taxes	(15,489)	(4,576)	22,881
Stock-based compensation	33,363	28,027	23,021
Goodwill impairment	37,120	0	0
Impairment of long-lived assets	5,350	0	0
Unrealized losses (gains) on foreign currency transactions	11,004	(2,670)	7,949
Other	3,320	(3,586)	986
Provisions for inventory, warranty and bad debt	63,752	38,862	44,978
Changes in assets and liabilities that (used) provided cash, net of acquisitions:
Accounts receivable	9,776	(18,814)	(63,225)
Inventories	(28,105)	(135,440)	(71,080)
Prepaid expenses and other current assets	18,405	(7,062)	(911)
Accounts payable	(10,257)	(1,426)	2,309
Accrued expenses and other liabilities	(37,310)	(19,666)	9,612
Income and other taxes payable	(43,937)	35,212	16,719
Net cash provided by operating activities	323,521	393,301	405,395
Cash flows from investing activities:
Purchases of property, plant and equipment	(133,536)	(160,343)	(126,535)
Proceeds from sales of property, plant and equipment	661	1,026	15,882
Proceeds from short-term investments	768,078	470,328	212,515
Purchases of short and long-term investments	(760,300)	(765,310)	(211,832)
Acquisitions of businesses, net of cash acquired	(15,115)	(109,115)	(60,483)
Other	237	415	(352)
Net cash used in investing activities	(139,975)	(562,999)	(170,805)
Cash flows from financing activities:
Proceeds from line-of-credit facilities	15	255	6,761
Payments on line-of-credit facilities	(15)	(255)	(6,761)
Proceeds on long-term borrowings	0	0	28,000
Principal payments on long-term borrowings	(3,671)	(3,604)	(19,842)
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	7,336	12,183	28,654
Cash contributed by non-controlling interest	0	839	0
Purchase of non-controlling interests	0	0	(197)
Purchase of treasury stock, at cost	(40,732)	(176,065)	(39,987)
Net cash used in financing activities	(37,067)	(166,647)	(3,372)
Effect of changes in exchange rates on cash, cash equivalents and restricted cash	(7,853)	(29,197)	54,827
Net increase (decrease) in cash, cash equivalents and restricted cash	138,626	(365,542)	286,045
Cash and cash equivalents — Beginning of period	544,358	909,900	623,855
Cash, cash equivalents and restricted cash — End of period (Note 1)	682,984	544,358	909,900
Supplemental disclosure of cash flow information:
Cash paid for interest	2,683	3,052	2,583
Cash paid for income taxes	116,951	112,762	155,559
Non-cash transactions:
Demonstration units transferred from inventory to other assets	10,367	6,270	4,114
Property, plant and equipment transferred from inventory	7,659	2,535	8,425
Changes in accounts payable related to property, plant and equipment	1,304	(2,852)	1,594
Leased assets obtained in exchange for new operating lease liabilities	$ 14,670	$ 0	$ 0

Nature Of Business And Summary

Nature Of Business And Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature Of Business And Summary Of Significant Accounting Policies	NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Nature of Business — IPG Photonics Corporation (the "Company" or "IPG") develops, manufactures and sells high-performance fiber lasers, fiber amplifiers, diode lasers, laser systems, communications systems and optical accessories that are used for diverse applications, primarily in materials processing. The Company was incorporated as a Delaware corporation in December 1998. Its world headquarters are located in Oxford, Massachusetts. It also has facilities and sales offices elsewhere in North and South America, Europe and Asia. Principles of Consolidation — The accompanying financial statements include the accounts of the Company and its majority-owned subsidiaries. All intercompany accounts and transactions have been eliminated. Use of Estimates — The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates. Foreign Currency — The financial information for entities outside the United States is measured using local currencies as the functional currency. Assets and liabilities are translated into U.S. dollars at the exchange rate in effect on the respective balance sheet dates. Income and expenses are translated into U.S. dollars based on the average rate of exchange for the corresponding period. Exchange rate differences resulting from translation adjustments are accounted for directly as a component of accumulated other comprehensive loss. Cash and Cash Equivalents and Short-Term and Long-Term Investments — Cash and cash equivalents consist primarily of highly liquid investments, such as bank deposits, mutual funds and marketable securities with maturities of three months or less at the date of purchase with insignificant interest rate risk. Short-term and long-term investments consist primarily of similar highly liquid investments and marketable securities with insignificant interest rate risks. Accounts Receivable and Allowance for Doubtful Accounts — Accounts receivable include $16,484 and $27,335 of bank acceptance drafts at December 31, 2019 and 2018, respectively. Bank acceptance drafts are bank guarantees of payment on specified dates. The weighted average maturity of these bank acceptance drafts is less than 76 days. The Company maintains an allowance for doubtful accounts to provide for the estimated amount of accounts receivable that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience and the age of outstanding receivables. Activity related to the allowance for doubtful accounts was as follows: 2019 2018 2017 Balance at January 1 $ 1,731 $ 2,198 $ 2,016 Provision for bad debts, net of recoveries 677 14 51 Uncollectable accounts written off (111) (198) (38) Foreign currency translation 102 (283) 169 Balance at December 31 $ 2,399 $ 1,731 $ 2,198 Inventories — Inventories are stated at the lower of cost or market on a first-in, first-out basis. Inventories include parts and components that may be specialized in nature and subject to rapid obsolescence. The Company periodically reviews the quantities and carrying values of inventories to assess whether the inventories are recoverable. The costs associated with provisions for excess quantities, technological obsolescence, or component rejections are charged to cost of sales as incurred. Goodwill — Goodwill is the amount by which the cost of the acquired net assets in a business acquisition exceeded the fair values of the net identifiable assets on the date of purchase. Goodwill is assessed for impairment at least annually, on a reporting unit basis, or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. The process of evaluating the potential impairment of goodwill is subjective and requires significant judgment at many points during the analysis. If the book value of a reporting unit exceeds its fair value, the implied fair value of goodwill is compared with the carrying amount of goodwill. If the carrying amount of goodwill exceeds the implied fair value, an impairment loss is recorded in an amount equal to that excess. The results of the goodwill assessment for the year ended December 31, 2019 are discussed in Note 7. Intangible Assets — Intangible assets result from the Company's various business acquisitions. Intangible assets are reported at cost, net of accumulated amortization, and are amortized on a straight-line basis either over their estimated useful lives of one year to thirteen years or over the period the economic benefits of the intangible asset are consumed. Property, Plant and Equipment — Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is determined using the straight-line method based on the estimated useful lives of the related assets. In the case of leasehold improvements, the estimated useful lives of the related assets do not exceed the remaining terms of the corresponding leases. The following table presents the assigned economic useful lives of property, plant and equipment: Category Economic Useful Life Buildings 20-30 years Machinery and equipment 5-7 years Office furniture and fixtures 5-7 years Expenditures for maintenance and repairs are charged to operating expense. Long-Lived Assets — Long-lived assets, which consist primarily of property, plant and equipment and identifiable intangible assets, are reviewed by management for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. When undiscounted expected future cash flows are less than the carrying value, an impairment loss is recorded equal to the amount by which the carrying value exceeds the fair value of assets. Impairments of long-lived assets for the year ended December 31, 2019 are discussed in Note 7. Included in other long-term assets is certain demonstration equipment. The demonstration equipment is amortized over the respective estimated economic lives, generally 3 years. The carrying value of the demonstration equipment totaled $7,591 and $7,037 at December 31, 2019 and 2018, respectively. Amortization expense of demonstration equipment for the years ended December 31, 2019, 2018 and 2017, was $4,364, $3,870 and $3,769, respectively. Authorized Capital — The Company has authorized capital stock consisting of 175,000,000 shares of common stock, par value $0.0001 per share, and 5,000,000 shares of preferred stock, par value $0.0001 per share. There are no shares of preferred stock outstanding as of December 31, 2019. 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 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 but which can occur over time for certain of the Company's systems contracts. 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 one 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 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 — Warranties are limited and provide that the product meets specifications and is free from defects in materials and workmanship. The Company also offers extended warranty agreements, which extend the standard warranty periods. 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. With the acquisition of Genesis Systems Group, LLC in December 2018, the Company enters into contracts to sell customized robotic systems, for which revenue is generally recognized over time, depending on the terms of the contract. Recognizing revenue over time for these contracts is based on the Company’s judgment that the customized robotic system does not have an alternative use and the Company has an enforceable right to payment for performance completed to date. The determination of the revenue to be recognized in a given period for performance obligations over time is based on the input method. The Company generally uses the total cost-to-cost input method of progress because it best depicts the transfer of control to the customer that occurs as costs are incurred. Under the cost-to-cost method, the extent of progress towards completion is measured based on the proportion of costs incurred to date to the total estimated costs at completion of the performance obligation. 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. Warranties — The Company typically provides one five Stock-Based Compensation — The Company accounts for stock-based compensation expense using the fair value of the awards granted. The Company estimates the fair value of stock options granted using the Black-Scholes model, it values restricted stock units using the intrinsic value method, and it uses a Monte Carlo simulation model to estimate the fair value of market-based performance stock units. The Company accounts for forfeitures as they occur. The Company amortizes the fair value of stock options and awards on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods. Stock options and restricted stock units generally vest annually on the anniversary of the grant date over a four Advertising Expense — The cost of advertising is expensed as incurred. The Company conducts substantially all of its sales and marketing efforts through trade shows, professional and technical conferences, direct sales and the Company's website. The Company's advertising costs were not material for the periods presented. Research and Development — Research and development costs are expensed as incurred. Restructuring — The Company records charges associated with approved restructuring plans to reorganize operations, to remove redundant headcount and infrastructure associated with business acquisitions or to improve the efficiency of business processes. Restructuring charges can include severance costs to eliminate a specific number of employees, infrastructure charges to vacate facilities and consolidate operations and contract cancellation costs. The Company records restructuring charges when they are probable and estimable. The Company accrues for severance and other employee separation costs under these plans when the employees accept the offer and the amount can be reasonably estimated. Income Taxes — Deferred tax assets and liabilities are recognized for the future tax consequences of temporary differences between the financial statement carrying amounts and tax basis of assets and liabilities and net operating loss and credit carryforwards using enacted rates in effect when those differences are expected to reverse. Valuation allowances are provided against deferred tax assets that are not deemed to be recoverable. The Company recognizes tax positions that are more likely than not to be sustained upon examination by relevant tax authorities. The tax positions are measured at the greatest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement. The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions and other issues. The reserves are based on a determination of whether and how much of a tax benefit taken in its tax filings or positions is more likely than not to be realized following resolution of uncertainties related to the tax benefit, assuming that the matter in question will be raised by the tax authorities. Concentration of Credit Risk — Financial instruments that potentially subject the Company to credit risk consist primarily of cash and cash equivalents, short and long-term investments, auction rate securities and accounts receivable. The Company maintains substantially all of its cash, short-term and long-term investments and marketable securities in various financial institutions, which it believes to be high-credit quality financial institutions. The Company grants credit to customers in the ordinary course of business and provides a reserve for potential credit losses. Such losses historically have been within management's expectations. One customer comprised 9%, 12% and 13% of net sales during the years ended December 31, 2019, 2018 and 2017 respectively. The same customer accounted for 24% and 25% of our net accounts receivable as of December 31, 2019 and 2018, respectively. The Company has historically depended on a few customers for a significant percentage of its annual net sales. The composition of this group can change from year to year. Net sales derived from the Company's five largest customers as a percentage of its annual net sales were 21%, 26% and 28% in 2019, 2018 and 2017, respectively. Comprehensive Income — Comprehensive income includes charges and credits to equity that are not the result of transactions with stockholders. Included within comprehensive income is the cumulative foreign currency translation adjustment, change in carrying value of auction rate securities, unrealized gains or losses on derivatives and unrealized gains or losses on available-for-sale investments. These adjustments are accumulated within the consolidated statements of comprehensive income. Total components of accumulated other comprehensive loss were as follows: December 31, 2019 2018 Foreign currency translation adjustments $ (147,161) $ (163,155) Unrealized gain on auction rate securities 232 232 Unrealized gain on derivatives, net of tax of $3 and $4, respectively 10 27 Accumulated other comprehensive loss $ (146,919) $ (162,896) 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. Business Segment Information — The Company operates in one segment which involves the design, development, production and distribution of fiber lasers, laser and non-laser systems, fiber amplifiers, and related optical components. The Company has a single, company-wide management team that administers all properties as a whole rather than as discrete operating segments. The chief operating decision maker, who is the Company's chief executive officer, measures financial performance as a single enterprise, and not on geography, legal entity, or end market basis. Throughout the year, the chief operating decision maker allocates capital resources on a project-by-project basis across the Company's entire asset base to maximize profitability without regard to geography, legal entity, or end market basis. The Company operates in a number of countries throughout the world in a variety of product lines. Information regarding product lines and geographic financial information is provided in Note 2, "Revenue from Contracts with Customers" and Note 8, "Property, Plant and Equipment." Earnings Per Share — Basic net income per share is computed by dividing net income attributable to shareholders of the Company by the weighted-average number of common shares outstanding during the reporting period. Diluted net income per share is computed similarly to basic net income per share, except that it includes the potential dilution that could occur if dilutive securities were exercised. Information about potentially dilutive and antidilutive shares for the reporting period is provided in Note 18, "Net Income Attributable to IPG Photonics Corporation Per Share." Leases — The Company determines if an arrangement is a lease at inception. Operating leases are included in other assets, other current liabilities, and other long-term liabilities on the Company's consolidated balance sheets. Right of use ("ROU") assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of the Company's leases do not provide an implicit rate, IPG uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The ROU assets also include any lease payments made and initial direct costs incurred and exclude lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company has lease agreements with lease and non-lease components, which are accounted for as a single lease component. Recent Accounting Pronouncements Adopted Pronouncements — In February 2016, the Financial Accounting Standards Board (“FASB”) issued a new standard related to leases to increase transparency and comparability among organizations by requiring the recognition of ROU assets and lease liabilities on the balance sheet. Most prominent among the changes in the standard is the recognition of ROU assets and lease liabilities by lessees for those leases classified as operating leases. The Company adopted ASC 842, as of January 1, 2019, using the modified retrospective approach as of the date of adoption. Under this approach, comparative periods have not been restated. In addition, IPG elected the package of three practical expedients permitted under the transition guidance within the new standard, which among other things, allowed for the carry forward of the historical lease classification. The cumulative effect of the changes made to the Company's consolidated January 1, 2019 balance sheet for the adoption of ASC 842 related to operating leases was as follows: Balance at Adoption of Balance at December 31, 2018 ASC 842 January 1, 2019 Balance Sheet Prepaid expenses and other current assets $ 57,764 $ (324) $ 57,440 Other assets 18,932 19,463 38,395 Accrued expenses and other current liabilities 154,640 5,292 159,932 Deferred income taxes and other long-term liabilities 80,734 13,847 94,581 On January 1, 2018, the Company adopted FASB ASU No. 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash" ("ASU 2016-18"), which enhances and clarifies the guidance on the classification and presentation of restricted cash in the statement of cash flows and requires additional disclosure about restricted cash balances. The Company considers cash to be restricted when withdrawal or general use is legally restricted. The Company records restricted cash in other assets on the consolidated balance sheets and determines classification as current or long-term based on the expected duration of the restriction. The reconciliation of the Company's cash and cash equivalents in the consolidated balance sheets to cash, cash equivalents and restricted cash in the consolidated statement of cash flows is as follows: Balance at Balance at December 31, 2019 December 31, 2018 Cash and cash equivalents $ 680,070 $ 544,358 Restricted cash included in other assets 2,914 — Cash, cash equivalents and restricted cash $ 682,984 $ 544,358 Also on January 1, 2018, the Company adopted ASC 606 "Revenue from Contracts with Customers," ("ASC 606" or the "new revenue standard") 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. 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 allowed 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 eliminated the exception that prohibited 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. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles—Goodwill and Other (Topic 350)" ("ASU 2017-04"). ASU 2017-04 simplified the accounting for goodwill impairments by eliminating step 2 from the goodwill impairment test. The Company early adopted this standard, which was applied prospectively, during the first quarter of 2018. The Company performs its annual goodwill impairment assessment on October 1 of each year. 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 March 2016, the FASB issued ASU No. 2016-09, "Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting" ("ASU 2016-09"). ASU 2016-09 was intended to simplify several areas of accounting for share-based compensation arrangements, including income tax impact and classification on the consolidated statement of cash flows. ASU 2016-09 was effective for fiscal years, and interim periods within those years, beginning after December 15, 2016, and the Company adopted this statement effective January 1, 2017. Under ASU 2016-09, excess tax benefits and deficiencies as a result of stock option exercises and restricted stock unit vesting are being recognized as discrete items within income tax expense or benefit in the consolidated statements of comprehensive income in the reporting period in which they occur. The adoption of ASU 2016-09 also required the cumulative effect of initially applying the standard to be recorded as an adjustment to the opening balance of retained earnings of the annual reporting period that included the date of initial application. This resulted in a cumulative effect increase of $3,464 to retained earnings and deferred tax assets. Also, as a result of the adoption of ASU 2016-09, the Company made an accounting policy election to record forfeitures as they occur rather than by estimating expected forfeitures. The calculated cumulative effect was a decrease in retained earnings of $1,319 and an increase in deferred tax assets and additional paid-in capital of $759 and $2,078, respectively, as of January 1, 2017. Other Pronouncements Currently Under Evaluation — In June 2016, the FASB issued ASU No. 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"), which adds an impairment model (known as the current expected credit loss ("CECL") model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce the complexity by decreasing the number of credit impairment models that entities use to account for debt instruments. ASU 2016-03, along with its subsequent clarifications, is effective for fiscal years beginning after December 15, 2019. The Company does not expect this standard will have a material impact to net income.

Revenue From Contracts With Cus

Revenue From Contracts With Customers	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue From Contracts With Customers	REVENUE FROM CONTRACTS WITH CUSTOMERS Sales are derived from products for different applications: fiber lasers, diode lasers, diodes and systems for materials processing, fiber lasers and amplifiers for advanced applications, fiber amplifiers for communications applications, and fiber lasers for medical applications. The following tables represent a disaggregation of revenue from contracts with customers for the years ended December 31, 2019 and 2018: Twelve Months Ended December 31, 2019 2018 Sales by Application Materials processing $ 1,229,211 $ 1,374,448 Other applications 85,370 85,426 Total $ 1,314,581 $ 1,459,874 Twelve Months Ended December 31, 2019 2018 Sales by Product High Power Continuous Wave ("CW") Lasers $ 734,745 $ 909,726 Medium and Low Power CW Lasers 56,625 95,764 Pulsed Lasers 137,675 162,048 Quasi-Continuous Wave ("QCW") Lasers 56,440 66,700 Laser and Non-Laser Systems 141,647 59,330 Other Revenue including Amplifiers, Service, Parts, Accessories and Change in Deferred Revenue 187,449 166,306 Total $ 1,314,581 $ 1,459,874 Sales by Geography North America $ 280,886 $ 202,743 Europe: Germany 81,365 111,259 Other including Eastern Europe/CIS 249,871 296,917 Asia and Australia: China 491,890 629,079 Japan 71,757 87,619 Other 121,586 127,251 Rest of World 17,226 5,006 Total $ 1,314,581 $ 1,459,874 Timing of Revenue Recognition Goods and services transferred at a point in time $ 1,233,065 $ 1,447,343 Goods and services transferred over time 81,516 12,531 Total $ 1,314,581 $ 1,459,874 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 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 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. The timing of customer payments on contracts for the sale of customized robotic systems generally differs from the timing of revenue recognized, resulting in contract assets and liabilities. Contract assets are included within prepaid expense and other current assets on the consolidated balance sheets. Contract liabilities are included within accrued expenses and other current liabilities on the consolidated balance sheets. The following table reflects the changes in the Company's contract assets and liabilities for the years ended December 31, 2019 and 2018: December 31, December 31, December 31, January 1, 2019 2018 Change 2018 2018 Change Contract assets Contract assets $ 9,645 $ 10,102 $ (457) $ 10,102 $ — $ 10,102 Contract liabilities Contract liabilities - current 59,531 52,606 6,925 52,606 46,508 6,098 Contract liabilities - long-term 1,820 1,413 407 1,413 182 1,231 During the year ended December 31, 2019 and 2018, the Company recognized revenue of $45,223 and $40,944, respectively, that was included in the contract liabilities at the beginning of the period. The Company has elected the practical expedient in ASC 606-10-50-14, whereby the performance obligations for contracts with an original expected duration of one year or less are not disclosed. The following table represents the Company's remaining performance obligations from contracts that are recognized over time as of December 31, 2019: Remaining Performance Obligations 2020 2021 2022 2023 2024 2025 Total Revenue expected to be recognized for extended warranty agreements $ 4,105 $ 914 $ 498 $ 301 $ 87 $ 18 $ 5,923 Revenue to be earned over time from contracts to sell robotic systems 28,170 1,325 — — — — 29,495 Total $ 32,275 $ 2,239 $ 498 $ 301 $ 87 $ 18 $ 35,418

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS The Company's financial instruments consist of cash equivalents, short-term investments, accounts receivable, auction rate securities, accounts payable, drawings on revolving lines of credit, long-term debt, interest rate swaps and contingent purchase consideration. The valuation techniques used to measure fair value are based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect internal market assumptions. These two types of inputs create the following fair value hierarchy: Level 1, defined as observable inputs such as quoted prices for identical instruments in active markets; Level 2, defined as inputs other than quoted prices in active markets that are either directly or indirectly observable; and Level 3, defined as unobservable inputs for which little or no market data exists, therefore requiring an entity to develop its own assumptions. The 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 December 31, 2019, the Company's long-term notes consisted of a variable rate note and a fixed rate note, and the book value is considered a reasonable estimate of fair market value. The following table presents fair value information related to the Company's assets and liabilities measured at amortized cost on the Consolidated Balance Sheets with the exception of the interest rate swap, which is measured at fair value: Fair Value Measurements at December 31, 2019 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 155,080 $ 155,080 $ — $ — Commercial paper 54,712 — 54,712 — Short-term investments: Corporate bonds 259,422 259,422 — — Commercial paper 236,752 — 236,752 — Certificate of deposit 6,501 6,501 — — Long-term investments and other assets: Auction rate securities 592 — — 592 Interest rate swap 12 — 12 — Total assets $ 713,071 $ 421,003 $ 291,476 $ 592 Liabilities Long-term notes $ 42,004 $ — $ 42,004 $ — Contingent purchase consideration 273 — — 273 Total liabilities $ 42,277 $ — $ 42,004 $ 273 Fair Value Measurements at December 31, 2018 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 180,965 $ 180,965 $ — $ — U.S. Treasury and agency obligations 6,495 6,495 — — Commercial paper 78,948 — 78,948 — Short-term investments: U.S. Treasury and agency obligations 116,800 116,800 — — Corporate bonds 227,009 227,009 — — Commercial paper 156,321 — 156,321 — Long-term investments and other assets: Corporate bonds 3,859 3,859 — — Auction rate securities 847 — — 847 Interest rate swap 31 — 31 — Total assets $ 771,275 $ 535,128 $ 235,300 $ 847 Liabilities Long-term notes $ 45,378 $ — $ 45,378 $ — Contingent purchase consideration 898 — — 898 Total liabilities $ 46,276 $ — $ 45,378 $ 898 Short-term investments consist of liquid investments including U.S. government and government agency notes, corporate bonds, commercial paper and certificates of deposit with original maturities of greater than three months but less than one year and are recorded at amortized cost. The fair value of the short-term investments considered held-to-maturity as of December 31, 2019 and December 31, 2018 was $502,675 and $500,130, respectively, which represents an unrealized gain of $129 and unrealized loss of $302, respectively, as compared to the book value recorded on the consolidated balance sheets for the same periods. There were no long-term investments considered held-to-maturity as of December 31, 2019. The fair value of the long-term investments considered held-to-maturity as of December 31, 2018 was $3,859, which represents the book value recorded on the consolidated balance sheets for the same period. There were no impairments for the investments considered held-to-maturity at December 31, 2019 and December 31, 2018. The Company entered into an interest rate swap that is designated as a cash flow hedge associated with a new long-term note issued during the second quarter of 2016 that will terminate with the long-term note in May 2023. The fair value at December 31, 2019 for the interest rate swap considered pricing models whose inputs are observable for the securities held by the Company. Auction rate securities and contingent consideration are measured at fair value on a recurring basis using significant unobservable inputs (Level 3). 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 auction rate securities are considered available-for-sale securities. They had a cost basis of $592 and $847 at December 31, 2019 and December 31, 2018, respectively. There were no impairments for the available-for-sale securities at December 31, 2019 and December 31, 2018. The fair value of contingent 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 consideration. The following table presents information about the Company's movement in Level 3 assets and liabilities measured at fair value: 2019 2018 2017 Auction rate securities Balance, January 1 $ 847 $ 1,016 $ 1,144 Period transactions (264) (207) — Change in fair value 9 38 (128) Balance, December 31 $ 592 $ 847 $ 1,016 Contingent purchase consideration Balance, January 1 $ 898 $ 902 $ — Period transactions — — 902 Cash payments (632) — — Change in fair value (29) 48 — Foreign exchange adjustment 36 (52) — Balance, December 31 $ 273 $ 898 $ 902 The following table presents the effective maturity dates of debt investments as of December 31, 2019 and December 31, 2018: December 31, 2019 December 31, 2018 Book Value Fair Value Book Value Fair Value Investment maturity Held-to-maturity Less than 1 year $ 502,546 $ 502,675 $ 585,875 $ 585,573 1 through 5 years — — 3,859 3,859 Total $ 502,546 $ 502,675 $ 589,734 $ 589,432 Available-for-sale Greater than 5 years $ 592 $ 592 $ 847 $ 847

Inventories

Inventories	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following: December 31, 2019 2018 Components and raw materials $ 200,390 $ 233,594 Work-in-process 49,620 66,498 Finished goods 130,780 103,487 Total $ 380,790 $ 403,579 The Company recorded inventory provisions totaling $38,902, $12,981 and $16,946 for the years ended December 31, 2019, 2018 and 2017, respectively. These provisions relate to the recoverability of the value of inventories due to technological changes and excess quantities. These provisions are reported as a reduction to components and raw materials and finished goods.

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2019
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS During the first quarter of 2019, the Company acquired a provider of submarine networking technology and services based in Brazil ("SND") for $19,560, which represents the fair value on that date. Of the purchase price, $1,956 ($1,861 at December 31, 2019) was held back for potential post-closing adjustments related to government approval of licenses. This balance is included within accrued expenses and other liabilities on the consolidated balance sheets. In addition, $2,934 ($2,914 at December 31, 2019) was held back in a restricted bank account for potential post-closing adjustments related to seller indemnities. This restricted cash balance is included within other assets, and the liability related to the amount due to the sellers if the indemnities are satisfied is included within deferred income taxes and other long-term liabilities on the consolidated balance sheets. During the fourth quarter of 2019, the Company finalized the purchase price allocations related to the acquisition, which resulted in adjusting the amounts that were provisionally reported as intangible assets for production know-how and customer relationships to goodwill. This adjustment reduced intangible assets by $9,650 and increased goodwill by the same amount. Additionally, the change in the provisional amounts resulted in a decrease in amortization expense and accumulated amortization of $848, which relates to the previous quarters. After completion of the purchase price allocations, the $19,076 excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed was recorded to goodwill. The goodwill arising from this acquisition will not be deductible for tax purposes. During the fourth quarter of 2018, the Company acquired 100% of the membership units of Genesis System Group, LLC (“Genesis Systems”). Genesis Systems is based in Davenport, Iowa, and has production facilities in the United States, Mexico, and Japan. Genesis Systems develops innovative robotic system solutions for applications that include welding, non-destructive inspection, machine vision, materials handling, removal and dispensing. The Company paid $107,987 to acquire Genesis Systems, which represents the fair value on that date. The purchase price includes $448, which was paid for the working capital adjustment finalized in the first quarter of 2019. Of the purchase price, $1,350 remains in escrow for indemnities provided by the seller. As a result of the acquisition, the Company recorded intangible assets of $32,350 related to customer relationships with a weighted-average estimated useful life of 11 years and $11,350 related to technology, trademark and tradename with a weighted-average estimated useful life of 6 years. Any excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed is allocated to goodwill, which amounted to $45,684, most of which will be deductible for tax purposes. During the second quarter of 2018, the Company acquired 100% of the shares of robot concept GmbH (“RC”). RC is located near Munich, Germany, designs and manufactures customized laser systems. The purchase price was $4,453, which represents the fair value on that date. As a result of the acquisition, the Company recorded intangible assets of $111 related to customer relationships with a weighted-average estimated useful life of 1 year and $594 related to technology, trademark and tradename with a weighted-average estimated useful life of 10 years. 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 this acquisition will not be deductible for tax purposes. The fair values of net tangible assets and intangible assets acquired were based upon the Company's estimates and assumptions at the acquisition dates. The following table summarizes the allocation of the assets acquired and liabilities assumed at the acquisition dates for the year ended December 31, 2018: Genesis Systems RC Total Cash and cash equivalents $ 2,847 $ 30 $ 2,877 Assets acquired excluding cash and cash equivalents and deferred tax assets 39,262 2,151 41,413 Liabilities assumed excluding deferred tax liabilities (23,506) (1,932) (25,438) Deferred tax liabilities, net — (573) (573) Intangible assets 43,700 705 44,405 Total identifiable net assets 62,303 381 62,684 Goodwill 45,684 4,072 49,756 Total purchase price $ 107,987 $ 4,453 $ 112,440 The operating results of Genesis Systems are included in the consolidated results of operations from the date of acquisition. The impact of earnings from Genesis Systems from January 1, 2017 to the date of acquisition were not material to the Company. The following table presents consolidated pro forma information as if the acquisition had occurred on January 1, 2017: Pro forma (Unaudited) Years ended December 31, 2018 2017 Net sales $ 1,551,373 $ 1,511,051 During the fourth quarter of 2017, the Company acquired 100% of the shares of Laser Depth Dynamics Inc. (“LDD”). LDD, located in Kingston, Ontario, Canada, provides in-process quality monitoring and control solutions for laser-based welding applications. The purchase price was $9,992, which represents the fair value on that date. As a result of the acquisition, the Company recorded intangible assets of $1,006 related to customer relationships with a weighted-average estimated useful life of 6 years and $2,608 related to technology, trademark and tradename with a weighted-average estimated useful life of 6 years. Any excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed is allocated to goodwill, which amounted to $5,276. The goodwill arising from this acquisition will be deductible for tax purposes. During the third quarter of 2017, the Company acquired 100% of the membership units of Innovative Laser Technologies, LLC ("ILT") located in Minneapolis, Minnesota. ILT produces high precision laser-based systems for the medical device industry and other end user markets. The Company paid $40,256 to acquire ILT, which represents the fair value on that date. As a result of the acquisition, the Company recorded intangible assets of $11,660 related to customer relationships with an estimated useful life of 13 years and $7,480 related to technology, trademark and tradename with a weighted-average estimated useful life of 8 years. Any excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed is allocated to goodwill, which amounted to $19,467. The majority of goodwill arising from this acquisition will not be deductible for tax purposes. During the second quarter of 2017, the Company acquired 100% of the shares of OptiGrate Corporation ("OptiGrate") located in Oviedo, Florida. OptiGrate is a developer and manufacturer of volume Bragg gratings used in the production of lasers and laser diodes. The Company paid $16,870 to acquire OptiGrate, which represents the fair value on that date. As a result of the acquisition, the Company recorded intangible assets of $1,010 related to customer relationships with an estimated useful life of 4 years and $4,650 related to technology, trademark and tradename with a weighted-average estimated useful life of 9 years. Any excess of the acquisition consideration over the fair value of assets acquired and liabilities assumed is allocated to goodwill, which amounted to $8,900. The goodwill arising from this acquisition will not be deductible for tax purposes. The following table summarizes the allocation of the assets acquired and liabilities assumed at the acquisition dates for the year ended December 31, 2017: LDD ILT OptiGrate Total Cash and cash equivalents $ 1,002 $ 969 $ 3,714 $ 5,685 Assets acquired excluding cash and cash equivalents and deferred tax assets 1,346 14,353 1,351 17,050 Liabilities assumed excluding deferred tax liabilities (708) (11,669) (687) (13,064) Deferred tax liabilities, net (538) (2,004) (2,068) (4,610) Intangible assets 3,614 19,140 5,660 28,414 Total identifiable net assets 4,716 20,789 7,970 33,475 Goodwill 5,276 19,467 8,900 33,643 Total purchase price $ 9,992 $ 40,256 $ 16,870 $ 67,118 Results of operations for the businesses acquired above have been included in the Company's consolidated financial statements after the date of such acquisitions. Also, pro forma results of operations in accordance with authoritative guidance for prior periods have not been presented because the effect of the acquisitions were not material to the Company's prior period consolidated financial results.

Restructuring

Restructuring	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring	RESTRUCTURING In the second half of 2019, the Company undertook a strategic analysis of investments in new markets and solutions, including the additional investment required to enter and obtain significant market share in the submarine telecommunications industry. As a result of this analysis, in the fourth quarter of 2019, the Company decided to cease further investment in SND and is pursuing strategic alternatives for this business. As of December 31, 2019, the Company incurred cumulative pre-tax charges of $21,163, which includes a non-cash goodwill impairment loss of $17,795 and non-cash asset-related costs of $2,852. In addition, $202 of severance and employee benefit costs were incurred and $314 related to contract cancellations. In addition to the SND plan discussed above, the Company also implemented other restructuring programs globally, which were primarily focused on workforce reduction and facility consolidation. These programs resulted in expenses of $3,762, including $1,264 of severance and employee benefit costs and $2,498 of non-cash asset-related costs. The following table summarizes the Company's restructuring accrual at December 31, 2019 and changes during the year ended December 31, 2019: Severance and Employee Benefit Costs Contract Cancellations Total Balance at January 1, 2019 $ — $ — $ — Charges 1,466 314 1,780 Cash payments (1,317) (275) (1,592) Balance at December 31, 2019 $ 149 $ 39 $ 188

Goodwill And Intangible Assets

Goodwill And Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill And Intangible Assets	GOODWILL AND INTANGIBLE ASSETS The following table sets forth the changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018: 2019 2018 Balance at January 1 $ 100,722 $ 55,831 Adjustments to goodwill during the measurement period 448 (2,362) Goodwill arising from business combinations 19,076 47,705 Impairment losses (37,120) — Foreign exchange adjustment (1,034) (452) Balance at December 31 $ 82,092 $ 100,722 The Company tests its reporting units for impairment annually as of the first day of the fourth quarter, or more frequently if events or circumstances indicate it is more likely than not that the fair value of a reporting unit is less than its carrying amount. The Company performed the 2019 annual impairment test as of October 1, 2019. For certain reporting units, the Company performed a quantitative assessment using the discounted cash flow method under the income approach to estimate the fair value. As a result of the 2019 annual impairment test for the transceivers reporting unit, the Company recognized a non-cash impairment loss of $19,325, which was equal to the goodwill carrying amount prior to its impairment. The analysis considered lower than forecasted sales and profitability, as well as the impact of delays in new product launches. As part of the restructuring of the submarine telecommunications reporting unit discussed in Note 6, the Company recognized a non-cash impairment loss of $17,795, which decreases the net assets to the estimated net realizable value as of December 31, 2019. The carrying balance of goodwill at December 31, 2019 was net of accumulated impairments of $37,120. Intangible assets, subject to amortization, consisted of the following: December 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Customer relationships $ 57,866 $ (11,993) $ 45,873 11 years $ 57,849 $ (6,427) $ 51,422 11 years Technology, trademark and trade name 41,297 (16,128) 25,169 7 years 41,184 (10,474) 30,710 7 years Production know-how 9,180 (7,415) 1,765 7 years 9,211 (6,212) 2,999 7 years Patents 8,036 (6,572) 1,464 8 years 8,036 (6,028) 2,008 8 years Total $ 116,379 $ (42,108) $ 74,271 $ 116,280 $ (29,141) $ 87,139 Amortization expense for the years ended December 31, 2019, 2018 and 2017 was $12,945, $8,170 and $5,899, respectively. The estimated future amortization expense for intangibles as of December 31, 2019 is as follows: 2020 2021 2022 2023 2024 Thereafter Total $ 12,059 $ 11,692 $ 10,783 $ 9,855 $ 7,515 $ 22,367 $ 74,271

Property, Plant And Equipment

Property, Plant And Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant And Equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant, and equipment consist of the following: December 31, 2019 2018 Land $ 45,676 $ 41,937 Buildings 400,617 332,150 Machinery and equipment 449,783 384,259 Office furniture and fixtures 70,001 65,775 Construction-in-progress 44,201 54,454 Total property, plant and equipment 1,010,278 878,575 Accumulated depreciation (409,426) (335,507) Total property, plant and equipment — net $ 600,852 $ 543,068 The Company recorded depreciation expense of $78,959, $68,231 and $54,900 for the years ended December 31, 2019, 2018 and 2017, respectively. Long-lived assets include property, plant and equipment, related deposits on such assets and demonstration equipment. The geographic locations of the Company's long-lived assets, net, based on physical location of the assets, as of December 31, 2019 and 2018 are as follows: December 31, 2019 2018 United States $ 366,059 $ 346,343 Germany 86,881 81,218 Russia 84,471 76,359 China 8,933 9,123 Other 71,616 40,689 Total $ 617,960 $ 553,732

Accrued Expenses And Other Liab

Accrued Expenses And Other Liabilities	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Accounts Expenses And Other Liabilities	ACCRUED EXPENSES AND OTHER LIABILITIES Accrued expenses and other liabilities consist of the following: December 31, 2019 2018 Accrued compensation $ 48,881 $ 60,107 Contract liabilities 59,531 52,606 Current portion of accrued warranty 23,114 23,106 Short-term lease liabilities 5,300 — Other 12,956 18,821 Total $ 149,782 $ 154,640

Product Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2019
Product Warranties Disclosures [Abstract]
Product Warranties	PRODUCT WARRANTIES Activity related to the warranty accrual was as follows: 2019 2018 2017 Balance at January 1 $ 51,422 $ 47,517 $ 33,978 Provision for warranty accrual 22,613 24,948 26,995 Warranty claims (24,826) (18,922) (16,250) Foreign currency translation and other (343) (2,121) 2,794 Balance at December 31 $ 48,866 $ 51,422 $ 47,517 Accrued warranty reported in the accompanying consolidated financial statements as of December 31, 2019 and December 31, 2018 consists of $23,114 and $23,106 in accrued expenses and other liabilities and $25,752 and $28,316 in other long-term liabilities, respectively.

Financing Arrangements

Financing Arrangements	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Financing Arrangements	FINANCING ARRANGEMENTS The Company's borrowings under existing financing arrangements consist of the following: December 31, 2019 2018 Term debt: Long-term notes $ 41,708 $ 45,378 Less: current portion (3,740) (3,671) Total long-term debt $ 37,968 $ 41,707 Term Debt: Long-Term Notes — At December 31, 2019, the outstanding principal balance on the long-term notes was $41,708 of which $3,740 is the current portion. The Company has an unsecured long-term note of $19,594 of which $1,188 is the current portion. The interest on this unsecured long-term note is variable at 1.20% above LIBOR and is fixed using an interest rate swap at 2.85% per annum. The unsecured long-term note matures in May 2023, at which time the outstanding principal balance will be $15,438. The Company has another note that is secured by the corporate aircraft with an outstanding principal balance of $22,114 of which $2,552 is the current portion. The interest on this collateralized long-term note is fixed at 2.74% per annum. The collateralized long-term note matures in July 2022, at which time the outstanding principal balance will be $15,375. The future principal payments for the Company’s Notes as of December 31, 2019 are as follows: 2020 $ 3,740 2021 3,810 2022 18,126 2023 16,032 Total $ 41,708 Revolving Line of Credit Facilities: U.S. Line of Credit — The Company maintains an unsecured revolving line of credit with available principal of up to $50,000, expiring in April 2020. The line of credit bears interest at a variable rate of LIBOR plus 0.80% to 1.20% depending on the Company's financial performance. Part of this credit facility is available to the Company's foreign subsidiaries including those in India, China, Japan and South Korea based on management discretion. At December 31, 2019, there were no outstanding drawings, however, there were $1,426 of guarantees issued against the line which reduced the total availability. At December 31, 2019, the remaining availability under this line was $48,574. The Company is required to meet certain financial covenants associated with its U.S. line of credit and collateralized long-term note. These covenants, tested quarterly, include a debt service coverage ratio and a funded debt to earnings before interest, taxes, depreciation and amortization ("EBITDA") ratio. The debt service coverage covenant requires the Company to maintain a trailing twelve month ratio of cash flow to debt service that is greater than 1.5:1. Debt service in the calculation is decreased by cash held in the U.S. in excess of $50,000 up to a maximum of $250,000. Cash flow is defined as EBITDA less unfunded capital expenditures. The funded debt to EBITDA covenant requires that the sum of all indebtedness for borrowed money on a consolidated basis be less than three times the Company's trailing twelve months EBITDA. Euro Line of Credit — The Company maintains an unsecured revolving line of credit with a principal amount of Euro 50,000 ($56,074 at December 31, 2019), expiring in July 2020. The line of credit bears interest at various rates based upon the type of loan. This credit facility is available to the Company's foreign subsidiaries including those in Germany, Russia, China and Italy based on management discretion. At December 31, 2019, there were no drawings, however, there were $1,422 of guarantees issued against the line which reduced the total availability. At December 31, 2019, the remaining availability under this line was $54,652. Other European Facilities — The Company maintains two Euro credit lines in Italy with aggregate available principal of Euro 2,000 ($2,243 as of December 31, 2019), with no expiration date, which bear interest at market rates that reset at the beginning of each quarter. At December 31, 2019, there were no outstanding drawings and the aggregate remaining availability under these lines was $2,243. These facilities are collateralized by a common pool of the assets of the Company's Italian subsidiary.

Derivative Instruments

Derivative Instruments	12 Months Ended
	Dec. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments	DERIVATIVE INSTRUMENTS The Company's only outstanding derivative financial instrument is an interest rate swap that is classified as a cash flow hedge of its variable rate debt. The fair value amounts in the consolidated balance sheets were: Notional Amounts 1 Other Assets December 31, December 31, 2019 2018 2019 2018 $ 19,594 $ 20,781 $ 13 $ 31 1. Notional amounts represent the gross contract/notional amount of the derivative outstanding. The derivative gains and losses in the consolidated financial statements for the years ended December 31, 2019, 2018 and 2017, related to the Company's current and previous interest rate swap contracts were as follows: Year Ended December 31, 2019 2018 2017 Effective portion recognized in other comprehensive income (loss), pretax: Interest rate swap $ (18) $ 15 $ (61) During the year ended December 31, 2018, the Company also entered into foreign currency forward contracts to hedge the value of intercompany dividends declared and paid in Euros by the Company's German subsidiary. These contracts were not designated as hedging instruments for accounting purposes and were fully settled during 2018. Losses associated with derivative instruments not designated as hedging instruments were as follows: Year Ended December 31, Classification 2019 2018 2017 Losses recognized in income Gain (loss) on foreign exchange $ — $ (19) $ —

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Leases	LEASES The Company leases certain warehouses, office spaces, land, vehicles and equipment under operating lease agreements. The remaining terms of these leases range from less than 1 year to 46 years. The operating lease expense for the years ended December 31, 2019, 2018 and 2017, totaled $8,800, $6,175 and $8,095, respectively. The cash paid for amounts included in the measurement of lease liabilities included in the operating cash flows from operating leases was $6,802 for the year ended December 31, 2019. The Company does not have any finance lease arrangements. The Company's operating lease assets and lease liabilities consist of the following as of December 31, 2019: Account Classification Amount Right-of-use assets Other assets $ 23,028 Short-term lease liabilities Accrued expenses and other liabilities 5,300 Long-term lease liabilities Deferred income taxes and other long-term liabilities 20,410 Total lease liabilities $ 25,710 The table below presents the future minimum lease payments to be made under non-cancelable operating leases as of December 31, 2018: Years ending December 31, 2019 $ 6,314 2020 4,603 2021 3,358 2022 2,596 2023 2,078 Thereafter 11,340 Total $ 30,289 The table below presents the maturities of operating lease liabilities as of December 31, 2019: 2020 $ 6,004 2021 4,785 2022 3,581 2023 2,964 2024 2,136 Thereafter 10,327 Total future minimum lease payments 29,797 Less: imputed interest (4,087) Present value of lease liabilities $ 25,710 Other information relevant to the Company's operating leases consist of the following as of December 31, 2019: Weighted-average remaining lease term 9 years Weighted-average discount rate 3.58 %

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES Employment Agreements — The Company has entered into employment agreements with certain members of senior management. The terms of these agreements are up to three Contractual Obligations — The Company has entered into various purchase obligations that include agreements for construction of buildings, raw materials and equipment. Obligations under these agreements were $53,922 and $114,396 as of December 31, 2019 and 2018, respectively. Legal proceedings — 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 matters. As of December 31, 2019 and through the date of the Company's subsequent review period of February 24, 2020, the Company has no legal proceedings ongoing that management estimates could have a material effect on the Company's Consolidated Financial Statements.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION Stock-based compensation is included in the following financial statement captions: Year Ended December 31, 2019 2018 2017 Cost of sales $ 9,249 $ 6,535 $ 5,863 Sales and marketing 3,815 2,550 2,041 Research and development 7,690 6,410 5,001 General and administrative 12,824 12,532 10,116 Total stock-based compensation 33,578 28,027 23,021 Tax benefit recognized (5,114) (6,632) (7,367) Net stock-based compensation $ 28,464 $ 21,395 $ 15,654 Incentive Plans — In February 2006, the Company's board of directors adopted the 2006 Incentive Compensation Plan (the "2006 Plan"), which provides for the issuance of stock options, restricted stock units, performance stock units, other equity-based awards and cash awards to the Company's directors, employees, consultants and advisors. In June 2006, the Company's board of directors adopted the Non-Employee Directors Stock Plan (the "Directors Plan") for non-employee directors, which was subsequently merged into the 2006 Plan. A total of 10,363,465 shares are reserved under the 2006 Plan. At December 31, 2019, 3,172,643 shares of the Company's stock were available for future grant under the 2006 Plan. The Company may grant stock options only at an exercise price equal to or greater than the fair market value of its common stock on the date of grant. Equity awards generally become exercisable over periods of one four ten two The Company grants performance stock units to executive officers. The performance stock unit agreements provide for the award of performance stock units with each unit representing the right to receive one share of the Company's common stock to be issued after the applicable award vesting period. The final number of units awarded, if any, for these performance grants will be determined as of the vesting dates, based upon the Company's total shareholder return over the performance period compared to the Russell 3000 Index for those awards granted prior to 2019 or compared to the S&P 1500 Composite / Electronic Equipment Instruments & Components Index for awards granted in 2019 and could range from between 0% and 200% of the amount of awarded units. The assumptions used in the Black-Scholes model for the calculation of compensation were as follows for the years ended December 31: 2019 2018 2017 Expected term 4.3 - 5.1 years 4.1 - 4.9 years 3.8 - 5.0 years Volatility 37% - 38% 31% - 36% 31% - 35% Risk-free rate of return 1.66% - 2.55% 2.54% - 3.01% 1.57% - 1.97% Dividend yield 0.25% 0.25% 0.25% Forfeiture rate —% —% —% The following table summarizes the option activity for the years ended December 31: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2017 2,064,253 $ 60.65 Granted 293,284 124.57 Exercised (546,931) 50.50 Forfeited (13,113) 90.81 Outstanding — December 31, 2017 1,797,493 73.95 6.02 $ 251,970 Granted 257,111 232.26 Exercised (282,720) 58.94 Forfeited (24,810) 131.36 Outstanding — December 31, 2018 1,747,074 98.93 5.80 $ 58,084 Granted 334,740 153.78 Exercised (192,533) 56.58 Forfeited (46,839) 149.64 Outstanding — December 31, 2019 1,842,442 $ 112.03 5.73 $ 85,110 Unvested — December 31, 2019 797,960 $ 149.66 7.96 $ 14,576 Exercisable — December 31, 2019 1,044,482 $ 83.29 4.02 $ 70,534 The intrinsic value of the options exercised during the years ended December 31, 2019, 2018 and 2017, was $17,891, $51,266 and $50,131, respectively. The weighted-average grant fair value per share for options granted during the years ended December 31, 2019, 2018 and 2017, was $53.52, $71.06 and $38.01, respectively. The total compensation cost related to non-vested awards not yet recorded at December 31, 2019 was $25,517 which is expected to be recognized over a weighted-average of 2.6 years. The following table summarizes the restricted stock units ("RSU's") activity for the years ended December 31: Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2017 366,770 $ 79.72 Granted 106,764 127.29 Vested (90,385) 66.18 Canceled (4,888) 90.54 Outstanding — December 31, 2017 378,261 96.23 2.55 $ 80,997 Granted 80,254 227.45 Vested (97,997) 91.62 Canceled (9,497) 121.37 Outstanding — December 31, 2018 351,021 126.93 2.62 $ 39,767 Granted 120,090 151.94 Vested (147,606) 120.58 Canceled (16,667) 139.73 Outstanding — December 31, 2019 306,838 $ 139.09 2.57 $ 44,467 The intrinsic value of the RSU's that vested during the years ended December 31, 2019, 2018 and 2017, was $22,638, $22,978 and $11,684, respectively. The weighted-average grant fair value per share for RSU's granted during the years ended December 31, 2019, 2018 and 2017, was $151.94, $227.45 and $127.29, respectively. The total compensation cost related to non-vested awards not yet recorded at December 31, 2019 was $26,231 which is expected to be recognized over a weighted-average of 2.6 years. The aggregate fair value of awards vested during the year ended December 31, 2019 was $17,799. The weighted-average fair value of the performance units was determined using the Monte Carlo simulation model incorporating the following weighted-average assumptions: 2019 2018 2017 Performance term 3.0 years 3.0 years 3.0 years Volatility 18% - 40% 13% - 32% 13% - 31% Risk-free rate of return 2.48% 2.41% 1.49% Dividend yield —% —% —% Weighted-average fair value per share $192.46 $284.78 $147.25 The following table summarizes the performance stock units ("PSU's") activity for the years ended December 31: Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2017 54,505 $ 108.51 Granted 21,444 147.25 Vested — Canceled — Outstanding — December 31, 2017 75,949 119.45 1.93 $ 16,263 Granted 33,706 238.12 Vested — Canceled — Outstanding — December 31, 2017 109,655 146.96 1.77 $ 12,423 Granted 34,989 190.83 Vested (43,594) 128.54 Canceled (1,208) 228.68 Outstanding — December 31, 2019 99,842 $ 162.34 1.84 $ 14,469 PSU's are included at 100% of target goal. The intrinsic value of the PSU's vested during the year ended December 31, 2019 was $6,830. The total compensation cost related to nonvested awards not yet recorded at December 31, 2019 was $5,833 which is expected to be recognized over a weighted average of 1.8 years. The aggregate fair value of awards vested during the year ended December 31, 2019 was $5,604.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Compensation Related Costs [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANSThe Company maintains a defined contribution retirement plan offered to all of its U.S. employees, as well as plans at certain foreign and domestic subsidiaries. The Company makes matching contributions to each plan, which amounted to approximately $6,005, $4,261 and $3,363, respectively for years ended December 31, 2019, 2018 and 2017.The Company has an employee stock purchase plan offered to its U.S. and German employees. The plan allows employees who participate to purchase shares of common stock through payroll deductions at a 15% discount to the lower of the stock price on the first day or the last day of the six

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES Income before the impact of income taxes for the years ended December 31 consisted of the following: 2019 2018 2017 U.S. $ 59,790 $ 146,855 $ 190,480 Foreign 188,586 387,540 361,391 Total $ 248,376 $ 534,395 $ 551,871 The Company's provision for income taxes for the years ended December 31 consisted of the following: 2019 2018 2017 Current: Federal $ 7,127 $ 7,274 $ 85,761 State 2,405 2,097 2,387 Foreign 74,072 125,431 93,254 Total current 83,604 134,802 181,402 Deferred: Federal (4,896) 2,497 12,459 State (1,658) 8,449 649 Foreign (8,935) (15,522) 9,773 Total deferred (15,489) (4,576) 22,881 Provision for income taxes $ 68,115 $ 130,226 $ 204,283 A reconciliation of income tax expense at the U.S. federal statutory income tax rate to the recorded tax provision for the years ended December 31, were as follows: 2019 2018 2017 Tax at statutory rate $ 52,159 $ 112,223 $ 193,155 Non-U.S. rate differential — net 14,958 26,985 (25,795) State income taxes — net 2,362 3,367 3,413 Stock-based compensation - tax benefit (5,114) (13,298) (14,015) Foreign derived intangible income benefit ("FDII") (4,763) (7,930) — Global intangible low-taxed income taxed in the U.S. ("GILTI") 4,648 5,955 — Goodwill impairment 10,009 — — Effect of 2017 U.S. Tax Cuts and Jobs Act — (4,747) 48,126 Withholding tax on intercompany dividend 3,122 — 2,225 Effect of changes in enacted tax rates on deferred tax assets and liabilities (639) 8,007 1,281 Federal and state tax credits (12,173) (11,024) (9,210) Change in reserves, including interest and penalties 779 2,290 4,350 Change in valuation allowance 4,515 7,421 (51) Other — net (1,748) 977 804 Provision for income taxes $ 68,115 $ 130,226 $ 204,283 The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, were as follows: 2019 2018 Property, plant and equipment $ (18,607) $ (22,443) Inventory provisions 23,611 12,963 Allowances and accrued liabilities 10,502 (2,599) Withholding tax on intercompany dividend (3,597) (2,225) Other tax credits 15,001 12,996 Deferred compensation 9,428 17,481 Net operating loss carryforwards 5,748 3,364 Valuation allowance (14,384) (7,910) Net deferred tax assets $ 27,702 $ 11,627 On December 22, 2017, the U.S. government enacted comprehensive tax legislation commonly referred to as the Tax Cuts and Jobs Act (the "Tax Act"). The Tax Act makes broad and complex changes to the U.S. tax code including, but not limited to, (1) reducing the U.S. federal corporate tax rate from 35% to 21%, (2) requiring a one-time transition tax on certain undistributed earnings of foreign subsidiaries that is payable over eight years, (3) generally eliminating U.S. federal income taxes on dividends from foreign subsidiaries, (4) providing an incentive benefit for U.S. income from intangibles (Foreign Derived Intangible Income); (5) increasing U.S. taxable income to include all income earned by foreign subsidiaries in excess of ten percent of the fixed assets in those entities (Global Intangible Low-taxed Income) and (6) providing for bonus depreciation that will allow for full expensing of qualified property. The Securities and Exchange Commission ("SEC") staff issued Staff Accounting Bulletin ("SAB") 118, which provides guidance on accounting for the tax effects of the Tax Act. SAB 118 provides a measurement period that should not extend beyond one year from the Tax Act enactment date for companies to complete the accounting under ASC 740. In accordance with SAB 118, a company must reflect the income tax effects of those aspects of the Tax Act for which the accounting under ASC 740 is complete. To the extent that a company's accounting for certain income tax effects of the Tax Act is incomplete but it is able to determine a reasonable estimate, it must record a provisional estimate in the financial statements. If a company cannot determine a provisional estimate to be included in the financial statements, it should continue to apply ASC 740 on the basis of the provisions of the tax laws that were in effect immediately before the enactment of the Tax Act. The final calculation for Deemed Repatriation Transition Tax on the 2017 tax return was $43,379. As of December 31, 2017, the Company had recorded a provisional expense for the Transition Tax of $48,126. The decrease of $4,747 was recorded as a reduction in tax expense in the third quarter of 2018. As the Transition Tax is payable over 8 years, $30,263 of this amount is included within other long-term liabilities on the consolidated balance sheets at both December 31, 2019 and 2018. In addition, the Company has calculated a $1,422 reduction in the valuation of net deferred tax assets related to the decrease in the U.S. federal tax rate. As of December 31, 2017, the Company had recorded a provisional decrease of $1,281. The increase of $141 was recorded as an increase to tax expense in the third quarter of 2018. The impact of other provisions in the Tax Act that were effective January 1, 2018, including the tax impact of the FDII and GILTI sections, are included in the effective tax rate calculation for 2019 and 2018. The Company has recorded $3,597 and $2,225 as a deferred tax liability on December 31, 2019 and 2018, respectively, for certain withholding and dividend taxes related to possible future distributions from its Russian subsidiary to their non-U.S. parent. The Company has paid dividends from its German subsidiary and continues to plan for future dividends to the extent the entity’s cash exceeds its operational and investment needs. Since there is no federal or withholding tax on such distributions, the Company has accrued only a state tax of $130 on a planned dividend of €150,000. With regard to future repatriation of undistributed earnings of other non-U.S. subsidiaries, the Company continues to consider these earnings to be indefinitely reinvested and, accordingly, has not recorded any deferred income taxes for the potential withholding or other taxes that would be assessed on such a repatriation to the U.S. At December 31, 2019 and 2018 , the cumulative undistributed earnings in non-U.S. subsidiaries were approximately $1,078,879 and $930,993 , respectively. In determining the Company’s 2019 and 2018 tax provisions under ASC 740, the Company calculated the deferred tax assets and liabilities for each separate tax entity. The Company then considered a number of factors including the positive and negative evidence regarding the realization of our deferred tax assets to determine whether a valuation allowance should be recognized with respect to our deferred tax assets. As of December 31, 2019 and 2018, the Company had state tax credit carry-forwards of $15,003 and $11,801, respectively. The state tax credit carry-forwards begin expiring in 2020. The Company has determined that it is not more likely than not that some of the state credits will be used before the expiration date and has accrued a valuation allowance of $10,632 and $7,439 as of December 31, 2019 and 2018, respectively. The Company has tax loss carryforwards in foreign jurisdictions totaling $13,218 and $2,888 as of December 31, 2019 and 2018, respectively. Some of these loss carryforwards start to expire in 2023 and some have an indefinite life but are limited in the amount that can be used in any year. The Company does not believe it is more likely than not that any of the loss carryforwards can be used and has provided a valuation allowance against the tax benefit of the losses in foreign jurisdictions of $3,753 and $474 at December 31, 2019 and 2018, respectively. The Company's acquisition of Menara Networks, Inc. ("Menara") in 2016 included net operating loss carry-forwards of $22,242. As of December 31, 2019 and 2018, the Company had $8,953 and $12,577 of these net operating loss carry-forwards remaining, respectively. No valuation allowance has been provided for these carry-forwards as the Company expects to be able to fully utilize them to offset future income. The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions and other issues. Reserves recorded are based on a determination of whether and how much of a tax benefit taken by us in our tax filings or positions is "more likely than not" to be realized following resolution of any potential contingencies present related to the tax benefit, assuming that the matter in question will be raised by the tax authorities. The following is a tabular reconciliation of the total amounts of unrecognized tax benefits: 2019 2018 Balance at January 1 $ 11,206 $ 10,370 Change in prior period positions (1,776) (1,067) Settlement of prior period position (230) — Additions for tax positions in current period 2,000 2,726 Foreign exchange adjustments $ 216 $ (823) Balance at December 31 $ 11,416 $ 11,206 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. Estimated penalties and interest related to the underpayment of income taxes were $543, $631 and $121 for the years ended December 31, 2019, 2018 and 2017, respectively, and are included within the provision for income taxes. Total accrued penalties and interest related to the underpayment of income taxes were $1,672 and $1,419 at December 31, 2019 and 2018, respectively. The Company's uncertain tax positions are related to tax years that remain subject to examination by the relevant taxing authorities. If these uncertain tax positions were realized, they would benefit the Company’s effective tax rate. The Company is currently under a tax audit in the U.S. for the years 2017 to 2018. Open tax years by major jurisdictions are: United States 2016 - 2019 Germany 2017 - 2019 Russia 2015 - 2019

Net Income Attributable To IPG

Net Income Attributable To IPG Photonics Corporation Per Share	12 Months Ended
	Dec. 31, 2019
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: Year Ended December 31, 2019 2018 2017 Net income attributable to IPG Photonics Corporation $ 180,234 $ 404,027 $ 347,614 Net income attributable to common stockholders 180,234 404,027 347,614 Weighted average shares 53,061 53,522 53,495 Dilutive effect of common stock equivalents 778 1,204 1,204 Diluted weighted average common shares 53,839 54,726 54,699 Basic net income attributable to IPG Photonics Corporation per share $ 3.40 $ 7.55 $ 6.50 Basic net income attributable to common stockholders $ 3.40 $ 7.55 $ 6.50 Diluted net income attributable to IPG Photonics Corporation per share $ 3.35 $ 7.38 $ 6.36 Diluted net income attributable to common stockholders $ 3.35 $ 7.38 $ 6.36 For the years ended December 31, 2019, 2018 and 2017, respectively, the computation of diluted weighted average common shares excludes common stock equivalents of 670,600 shares, 279,700 shares and 182,900 shares which includes RSU's of 58,700, 60,500 and 11,900, PSU's of 40,900, 14,900 and nil, and non-qualified stock options of 571,000, 204,300, and 171,000, respectively, because the effect would be anti-dilutive. On February 12, 2019, the Company announced that its board of directors authorized an anti-dilutive stock repurchase program (the "2019 Program"). Under the 2019 Program, IPG is authorized to repurchase shares of common stock in an amount not to exceed the lesser 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, 2019 through December 31, 2020 and (b) $125,000, exclusive of any fees, commissions or other expenses. Share repurchases will be made periodically in open market transactions using the Company's working capital, and are subject to market conditions, legal requirements and other factors. The 2019 Program authorization does not obligate the Company to repurchase any dollar amount or number of its shares, and repurchases may be commenced or suspended from time to time without prior notice. For the years ended December 31, 2019, 2018 and 2017, respectively, the Company repurchased 301,262 shares, 1,051,825 shares, and 275,495 shares of its common stock with an average price of $135.21, $167.39 and $145.15 per share in the open market. As of December 31, 2019 the remaining amount authorized under the 2019 Program is up to $84,268, but may be less depending upon the equity compensation and employee stock purchase plan dilution during the 2019 Program. The impact on the reduction of weighted average shares for years ended December 31, 2019, 2018 and 2017 was 97,054 shares, 363,936 shares and 160,440 shares, respectively.

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2019
Related Party Transactions [Abstract]
Related-Party Transactions	RELATED-PARTY TRANSACTIONSThe Company's Chief Executive Officer ("CEO") leases the annual right to use 25% of the Company's corporate aircraft under an October 2014 lease, which was superseded by a new lease signed in July 2017 in connection with the purchase of a different aircraft. The 2017 lease expires July 2022. The annual lease rate under the 2017 lease was $925 and future rent payments are adjusted annually. The annual lease rate under the 2014 lease was $651. The CEO paid the Company $924, $925, and $753 in 2019, 2018, and 2017, respectively, under the aircraft leases. There were no amounts due to the Company at December 31, 2019 or at December 31, 2018. The CEO directly pays an unrelated flight management firm for the operating costs of his private use including pilot fees, fuel and other costs. In 2019, 2018 and 2017, the Company purchased various equipment, parts and services from a company for which one of the Company's independent directors is chairman of its board of directors. The payments for 2019, 2018 and 2017 totaled $51, $947 and $2,296, respectively. There were no amounts due to this company at December 31, 2019 or at December 31, 2018.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2019
Selected Quarterly Financial Information [Abstract]
Selected Quarterly Financial Data (Unaudited)	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) 2019 First Quarter Second Quarter Third Quarter Fourth Quarter Net sales $ 315,047 $ 363,769 $ 329,138 $ 306,627 Gross profit 148,911 180,237 152,858 124,203 Net income (loss) attributable to IPG Photonics Corporation 55,159 72,272 57,253 (4,450) Net income (loss) per share, basic 1.04 1.36 1.08 (0.08) Net income (loss) per share, diluted 1.02 1.34 1.07 (0.08) 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Net sales $ 359,864 $ 413,613 $ 356,346 $ 330,051 Gross profit 203,362 234,975 195,184 166,747 Net income attributable to IPG Photonics Corporation 106,334 121,617 100,517 75,559 Net income per share, basic 1.98 2.27 1.88 1.42 Net income per share, diluted 1.93 2.21 1.84 1.40 Net income attributable to IPG Photonics Corporation as well as the basic and diluted loss per share in the fourth quarter of the year ended December 31, 2019 were impacted by goodwill impairment, impairment of long-lived assets and other restructuring charges discussed in Notes 6 and 7.

Nature Of Business And Summar_2

Nature Of Business And Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation — The accompanying financial statements include the accounts of the Company and its majority-owned subsidiaries. All intercompany accounts and transactions have been eliminated.
Use of Estimates	Use of Estimates — The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The Company bases its estimates on historical experience and on various other assumptions that are believed to be reasonable under the circumstances. Actual results could differ from those estimates.
Foreign Currency	Foreign Currency — The financial information for entities outside the United States is measured using local currencies as the functional currency. Assets and liabilities are translated into U.S. dollars at the exchange rate in effect on the respective balance sheet dates. Income and expenses are translated into U.S. dollars based on the average rate of exchange for the corresponding period. Exchange rate differences resulting from translation adjustments are accounted for directly as a component of accumulated other comprehensive loss.
Cash and Cash Equivalents and Short-Term and Long-term Investments	Cash and Cash Equivalents and Short-Term and Long-Term Investments — Cash and cash equivalents consist primarily of highly liquid investments, such as bank deposits, mutual funds and marketable securities with maturities of three months or less at the date of purchase with insignificant interest rate risk. Short-term and long-term investments consist primarily of similar highly liquid investments and marketable securities with insignificant interest rate risks.
Accounts Receivable and Allowance for Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts — Accounts receivable include $16,484 and $27,335 of bank acceptance drafts at December 31, 2019 and 2018, respectively. Bank acceptance drafts are bank guarantees of payment on specified dates. The weighted average maturity of these bank acceptance drafts is less than 76 days. The Company maintains an allowance for doubtful accounts to provide for the estimated amount of accounts receivable that will not be collected. The allowance is based upon an assessment of customer creditworthiness, historical payment experience and the age of outstanding receivables.
Inventories	Inventories — Inventories are stated at the lower of cost or market on a first-in, first-out basis. Inventories include parts and components that may be specialized in nature and subject to rapid obsolescence. The Company periodically reviews the quantities and carrying values of inventories to assess whether the inventories are recoverable. The costs associated with provisions for excess quantities, technological obsolescence, or component rejections are charged to cost of sales as incurred.
Goodwill	Goodwill — Goodwill is the amount by which the cost of the acquired net assets in a business acquisition exceeded the fair values of the net identifiable assets on the date of purchase. Goodwill is assessed for impairment at least annually, on a reporting unit basis, or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. The process of evaluating the potential impairment of goodwill is subjective and requires significant judgment at many points during the analysis. If the book value of a reporting unit exceeds its fair value, the implied fair value of goodwill is compared with the carrying amount of goodwill. If the carrying amount of goodwill exceeds the implied fair value, an impairment loss is recorded in an amount equal to that excess. The results of the goodwill assessment for the year ended December 31, 2019 are discussed in Note 7.
Intangible Assets	Intangible Assets — Intangible assets result from the Company's various business acquisitions. Intangible assets are reported at cost, net of accumulated amortization, and are amortized on a straight-line basis either over their estimated useful lives of one year to thirteen years or over the period the economic benefits of the intangible asset are consumed.
Property, Plant and Equipment	Property, Plant and Equipment — Property, plant and equipment are stated at cost, less accumulated depreciation. Depreciation is determined using the straight-line method based on the estimated useful lives of the related assets. In the case of leasehold improvements, the estimated useful lives of the related assets do not exceed the remaining terms of the corresponding leases.
Long-Lived Assets	Long-Lived Assets — Long-lived assets, which consist primarily of property, plant and equipment and identifiable intangible assets, are reviewed by management for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. When undiscounted expected future cash flows are less than the carrying value, an impairment loss is recorded equal to the amount by which the carrying value exceeds the fair value of assets.
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 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 but which can occur over time for certain of the Company's systems contracts. 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 one 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 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 — Warranties are limited and provide that the product meets specifications and is free from defects in materials and workmanship. The Company also offers extended warranty agreements, which extend the standard warranty periods. 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. With the acquisition of Genesis Systems Group, LLC in December 2018, the Company enters into contracts to sell customized robotic systems, for which revenue is generally recognized over time, depending on the terms of the contract. Recognizing revenue over time for these contracts is based on the Company’s judgment that the customized robotic system does not have an alternative use and the Company has an enforceable right to payment for performance completed to date. The determination of the revenue to be recognized in a given period for performance obligations over time is based on the input method. The Company generally uses the total cost-to-cost input method of progress because it best depicts the transfer of control to the customer that occurs as costs are incurred. Under the cost-to-cost method, the extent of progress towards completion is measured based on the proportion of costs incurred to date to the total estimated costs at completion of the performance obligation. Customer Deposits and Deferred Revenue —
Warranties	Warranties — The Company typically provides one five
Stock-Based Compensation	Stock-Based Compensation — The Company accounts for stock-based compensation expense using the fair value of the awards granted. The Company estimates the fair value of stock options granted using the Black-Scholes model, it values restricted stock units using the intrinsic value method, and it uses a Monte Carlo simulation model to estimate the fair value of market-based performance stock units. The Company accounts for forfeitures as they occur. The Company amortizes the fair value of stock options and awards on a straight-line basis over the requisite service periods of the awards, which are generally the vesting periods. Stock options and restricted stock units generally vest annually on the anniversary of the grant date over a four
Advertising Expenses	Advertising Expense — The cost of advertising is expensed as incurred. The Company conducts substantially all of its sales and marketing efforts through trade shows, professional and technical conferences, direct sales and the Company's website. The Company's advertising costs were not material for the periods presented.
Research and Development	Research and Development — Research and development costs are expensed as incurred.
Restructuring	Restructuring — The Company records charges associated with approved restructuring plans to reorganize operations, to remove redundant headcount and infrastructure associated with business acquisitions or to improve the efficiency of business processes. Restructuring charges can include severance costs to eliminate a specific number of employees, infrastructure charges to vacate facilities and consolidate operations and contract cancellation costs. The Company records restructuring charges when they are probable and estimable. The Company accrues for severance and other employee separation costs under these plans when the employees accept the offer and the amount can be reasonably estimated.
Income Taxes	Income Taxes — Deferred tax assets and liabilities are recognized for the future tax consequences of temporary differences between the financial statement carrying amounts and tax basis of assets and liabilities and net operating loss and credit carryforwards using enacted rates in effect when those differences are expected to reverse. Valuation allowances are provided against deferred tax assets that are not deemed to be recoverable. The Company recognizes tax positions that are more likely than not to be sustained upon examination by relevant tax authorities. The tax positions are measured at the greatest amount of tax benefit that is more than 50 percent likely to be realized upon ultimate settlement. The Company provides reserves for potential payments of tax to various tax authorities related to uncertain tax positions and other issues. The reserves are based on a determination of whether and how much of a tax benefit taken in its tax filings or positions is more likely than not to be realized following resolution of uncertainties related to the tax benefit, assuming that the matter in question will be raised by the tax authorities.
Concentration of Credit Risk	Concentration of Credit Risk — Financial instruments that potentially subject the Company to credit risk consist primarily of cash and cash equivalents, short and long-term investments, auction rate securities and accounts receivable. The Company maintains substantially all of its cash, short-term and long-term investments and marketable securities in various financial institutions, which it believes to be high-credit quality financial institutions. The Company grants credit to customers in the ordinary course of business and provides a reserve for potential credit losses. Such losses historically have been within management's expectations.
Comprehensive Income	Comprehensive Income — Comprehensive income includes charges and credits to equity that are not the result of transactions with stockholders. Included within comprehensive income is the cumulative foreign currency translation adjustment, change in carrying value of auction rate securities, unrealized gains or losses on derivatives and unrealized gains or losses on available-for-sale investments. These adjustments are accumulated within the consolidated statements of comprehensive income.
Derivative 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.
Business Segment Information	Business Segment Information — The Company operates in one segment which involves the design, development, production and distribution of fiber lasers, laser and non-laser systems, fiber amplifiers, and related optical components. The Company has a single, company-wide management team that administers all properties as a whole rather than as discrete operating segments. The chief operating decision maker, who is the Company's chief executive officer, measures financial performance as a single enterprise, and not on geography, legal entity, or end market basis. Throughout the year, the chief operating decision maker allocates capital resources on a project-by-project basis across the Company's entire asset base to maximize profitability without regard to geography, legal entity, or end market basis. The Company operates in a number of countries throughout the world in a variety of product lines. Information regarding product lines and geographic financial information is provided in Note 2, "Revenue from Contracts with Customers" and Note 8, "Property, Plant and Equipment."
Earnings Per Share	Earnings Per Share — Basic net income per share is computed by dividing net income attributable to shareholders of the Company by the weighted-average number of common shares outstanding during the reporting period. Diluted net income per share is computed similarly to basic net income per share, except that it includes the potential dilution that could occur if dilutive securities were exercised. Information about potentially dilutive and antidilutive shares for the reporting period is provided in Note 18, "Net Income Attributable to IPG Photonics Corporation Per Share."
Leases	Leases — The Company determines if an arrangement is a lease at inception. Operating leases are included in other assets, other current liabilities, and other long-term liabilities on the Company's consolidated balance sheets. Right of use ("ROU") assets and lease liabilities are recognized based on the present value of the future minimum lease payments over the lease term at commencement date. As most of the Company's leases do not provide an implicit rate, IPG uses its incremental borrowing rate based on the information available at commencement date in determining the present value of future payments. The ROU assets also include any lease payments made and initial direct costs incurred and exclude lease incentives. Lease terms may include options to extend or terminate the lease when it is reasonably certain that we will exercise that option. Lease expense for minimum lease payments is recognized on a straight-line basis over the lease term. Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Company recognizes lease expense for these leases on a straight-line basis over the lease term. The Company has lease agreements with lease and non-lease components, which are accounted for as a single lease component.
Recent Accounting Pronouncements	Recent Accounting Pronouncements Adopted Pronouncements — In February 2016, the Financial Accounting Standards Board (“FASB”) issued a new standard related to leases to increase transparency and comparability among organizations by requiring the recognition of ROU assets and lease liabilities on the balance sheet. Most prominent among the changes in the standard is the recognition of ROU assets and lease liabilities by lessees for those leases classified as operating leases. The Company adopted ASC 842, as of January 1, 2019, using the modified retrospective approach as of the date of adoption. Under this approach, comparative periods have not been restated. In addition, IPG elected the package of three practical expedients permitted under the transition guidance within the new standard, which among other things, allowed for the carry forward of the historical lease classification. The cumulative effect of the changes made to the Company's consolidated January 1, 2019 balance sheet for the adoption of ASC 842 related to operating leases was as follows: Balance at Adoption of Balance at December 31, 2018 ASC 842 January 1, 2019 Balance Sheet Prepaid expenses and other current assets $ 57,764 $ (324) $ 57,440 Other assets 18,932 19,463 38,395 Accrued expenses and other current liabilities 154,640 5,292 159,932 Deferred income taxes and other long-term liabilities 80,734 13,847 94,581 On January 1, 2018, the Company adopted FASB ASU No. 2016-18, "Statement of Cash Flows (Topic 230): Restricted Cash" ("ASU 2016-18"), which enhances and clarifies the guidance on the classification and presentation of restricted cash in the statement of cash flows and requires additional disclosure about restricted cash balances. The Company considers cash to be restricted when withdrawal or general use is legally restricted. The Company records restricted cash in other assets on the consolidated balance sheets and determines classification as current or long-term based on the expected duration of the restriction. The reconciliation of the Company's cash and cash equivalents in the consolidated balance sheets to cash, cash equivalents and restricted cash in the consolidated statement of cash flows is as follows: Balance at Balance at December 31, 2019 December 31, 2018 Cash and cash equivalents $ 680,070 $ 544,358 Restricted cash included in other assets 2,914 — Cash, cash equivalents and restricted cash $ 682,984 $ 544,358 Also on January 1, 2018, the Company adopted ASC 606 "Revenue from Contracts with Customers," ("ASC 606" or the "new revenue standard") 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. 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 allowed 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 eliminated the exception that prohibited 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. In January 2017, the FASB issued ASU No. 2017-04, "Intangibles—Goodwill and Other (Topic 350)" ("ASU 2017-04"). ASU 2017-04 simplified the accounting for goodwill impairments by eliminating step 2 from the goodwill impairment test. The Company early adopted this standard, which was applied prospectively, during the first quarter of 2018. The Company performs its annual goodwill impairment assessment on October 1 of each year. 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 March 2016, the FASB issued ASU No. 2016-09, "Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting" ("ASU 2016-09"). ASU 2016-09 was intended to simplify several areas of accounting for share-based compensation arrangements, including income tax impact and classification on the consolidated statement of cash flows. ASU 2016-09 was effective for fiscal years, and interim periods within those years, beginning after December 15, 2016, and the Company adopted this statement effective January 1, 2017. Under ASU 2016-09, excess tax benefits and deficiencies as a result of stock option exercises and restricted stock unit vesting are being recognized as discrete items within income tax expense or benefit in the consolidated statements of comprehensive income in the reporting period in which they occur. The adoption of ASU 2016-09 also required the cumulative effect of initially applying the standard to be recorded as an adjustment to the opening balance of retained earnings of the annual reporting period that included the date of initial application. This resulted in a cumulative effect increase of $3,464 to retained earnings and deferred tax assets. Also, as a result of the adoption of ASU 2016-09, the Company made an accounting policy election to record forfeitures as they occur rather than by estimating expected forfeitures. The calculated cumulative effect was a decrease in retained earnings of $1,319 and an increase in deferred tax assets and additional paid-in capital of $759 and $2,078, respectively, as of January 1, 2017. Other Pronouncements Currently Under Evaluation — In June 2016, the FASB issued ASU No. 2016-13, "Measurement of Credit Losses on Financial Instruments" ("ASU 2016-13"), which adds an impairment model (known as the current expected credit loss ("CECL") model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce the complexity by decreasing the number of credit impairment models that entities use to account for debt instruments. ASU 2016-03, along with its subsequent clarifications, is effective for fiscal years beginning after December 15, 2019. The Company does not expect this standard will have a material impact to net income.

Nature Of Business And Summar_3

Nature Of Business And Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule Of Allowance For Doubtful Accounts	Activity related to the allowance for doubtful accounts was as follows: 2019 2018 2017 Balance at January 1 $ 1,731 $ 2,198 $ 2,016 Provision for bad debts, net of recoveries 677 14 51 Uncollectable accounts written off (111) (198) (38) Foreign currency translation 102 (283) 169 Balance at December 31 $ 2,399 $ 1,731 $ 2,198
Property, Plant and Equipment	The following table presents the assigned economic useful lives of property, plant and equipment: Category Economic Useful Life Buildings 20-30 years Machinery and equipment 5-7 years Office furniture and fixtures 5-7 years
Schedule of Accumulated Other Comprehensive Income (Loss)	Total components of accumulated other comprehensive loss were as follows: December 31, 2019 2018 Foreign currency translation adjustments $ (147,161) $ (163,155) Unrealized gain on auction rate securities 232 232 Unrealized gain on derivatives, net of tax of $3 and $4, respectively 10 27 Accumulated other comprehensive loss $ (146,919) $ (162,896)
Cumulative Effect of Change to Balance Sheet	The cumulative effect of the changes made to the Company's consolidated January 1, 2019 balance sheet for the adoption of ASC 842 related to operating leases was as follows: Balance at Adoption of Balance at December 31, 2018 ASC 842 January 1, 2019 Balance Sheet Prepaid expenses and other current assets $ 57,764 $ (324) $ 57,440 Other assets 18,932 19,463 38,395 Accrued expenses and other current liabilities 154,640 5,292 159,932 Deferred income taxes and other long-term liabilities 80,734 13,847 94,581 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)
Schedule of Restricted Cash	The reconciliation of the Company's cash and cash equivalents in the consolidated balance sheets to cash, cash equivalents and restricted cash in the consolidated statement of cash flows is as follows: Balance at Balance at December 31, 2019 December 31, 2018 Cash and cash equivalents $ 680,070 $ 544,358 Restricted cash included in other assets 2,914 — Cash, cash equivalents and restricted cash $ 682,984 $ 544,358
Schedule of Cash and Cash Equivalents	The reconciliation of the Company's cash and cash equivalents in the consolidated balance sheets to cash, cash equivalents and restricted cash in the consolidated statement of cash flows is as follows: Balance at Balance at December 31, 2019 December 31, 2018 Cash and cash equivalents $ 680,070 $ 544,358 Restricted cash included in other assets 2,914 — Cash, cash equivalents and restricted cash $ 682,984 $ 544,358

Revenue From Contracts With C_2

Revenue From Contracts With Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables represent a disaggregation of revenue from contracts with customers for the years ended December 31, 2019 and 2018: Twelve Months Ended December 31, 2019 2018 Sales by Application Materials processing $ 1,229,211 $ 1,374,448 Other applications 85,370 85,426 Total $ 1,314,581 $ 1,459,874 Twelve Months Ended December 31, 2019 2018 Sales by Product High Power Continuous Wave ("CW") Lasers $ 734,745 $ 909,726 Medium and Low Power CW Lasers 56,625 95,764 Pulsed Lasers 137,675 162,048 Quasi-Continuous Wave ("QCW") Lasers 56,440 66,700 Laser and Non-Laser Systems 141,647 59,330 Other Revenue including Amplifiers, Service, Parts, Accessories and Change in Deferred Revenue 187,449 166,306 Total $ 1,314,581 $ 1,459,874 Sales by Geography North America $ 280,886 $ 202,743 Europe: Germany 81,365 111,259 Other including Eastern Europe/CIS 249,871 296,917 Asia and Australia: China 491,890 629,079 Japan 71,757 87,619 Other 121,586 127,251 Rest of World 17,226 5,006 Total $ 1,314,581 $ 1,459,874 Timing of Revenue Recognition Goods and services transferred at a point in time $ 1,233,065 $ 1,447,343 Goods and services transferred over time 81,516 12,531 Total $ 1,314,581 $ 1,459,874
Changes in Contract Assets and Liabilities	The following table reflects the changes in the Company's contract assets and liabilities for the years ended December 31, 2019 and 2018: December 31, December 31, December 31, January 1, 2019 2018 Change 2018 2018 Change Contract assets Contract assets $ 9,645 $ 10,102 $ (457) $ 10,102 $ — $ 10,102 Contract liabilities Contract liabilities - current 59,531 52,606 6,925 52,606 46,508 6,098 Contract liabilities - long-term 1,820 1,413 407 1,413 182 1,231
Schedule of Remaining Performance Obligations	The following table represents the Company's remaining performance obligations from contracts that are recognized over time as of December 31, 2019: Remaining Performance Obligations 2020 2021 2022 2023 2024 2025 Total Revenue expected to be recognized for extended warranty agreements $ 4,105 $ 914 $ 498 $ 301 $ 87 $ 18 $ 5,923 Revenue to be earned over time from contracts to sell robotic systems 28,170 1,325 — — — — 29,495 Total $ 32,275 $ 2,239 $ 498 $ 301 $ 87 $ 18 $ 35,418

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value	The following table presents fair value information related to the Company's assets and liabilities measured at amortized cost on the Consolidated Balance Sheets with the exception of the interest rate swap, which is measured at fair value: Fair Value Measurements at December 31, 2019 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 155,080 $ 155,080 $ — $ — Commercial paper 54,712 — 54,712 — Short-term investments: Corporate bonds 259,422 259,422 — — Commercial paper 236,752 — 236,752 — Certificate of deposit 6,501 6,501 — — Long-term investments and other assets: Auction rate securities 592 — — 592 Interest rate swap 12 — 12 — Total assets $ 713,071 $ 421,003 $ 291,476 $ 592 Liabilities Long-term notes $ 42,004 $ — $ 42,004 $ — Contingent purchase consideration 273 — — 273 Total liabilities $ 42,277 $ — $ 42,004 $ 273 Fair Value Measurements at December 31, 2018 Total Level 1 Level 2 Level 3 Assets Cash equivalents: Money market fund deposits and term deposits $ 180,965 $ 180,965 $ — $ — U.S. Treasury and agency obligations 6,495 6,495 — — Commercial paper 78,948 — 78,948 — Short-term investments: U.S. Treasury and agency obligations 116,800 116,800 — — Corporate bonds 227,009 227,009 — — Commercial paper 156,321 — 156,321 — Long-term investments and other assets: Corporate bonds 3,859 3,859 — — Auction rate securities 847 — — 847 Interest rate swap 31 — 31 — Total assets $ 771,275 $ 535,128 $ 235,300 $ 847 Liabilities Long-term notes $ 45,378 $ — $ 45,378 $ — Contingent purchase consideration 898 — — 898 Total liabilities $ 46,276 $ — $ 45,378 $ 898
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: 2019 2018 2017 Auction rate securities Balance, January 1 $ 847 $ 1,016 $ 1,144 Period transactions (264) (207) — Change in fair value 9 38 (128) Balance, December 31 $ 592 $ 847 $ 1,016 Contingent purchase consideration Balance, January 1 $ 898 $ 902 $ — Period transactions — — 902 Cash payments (632) — — Change in fair value (29) 48 — Foreign exchange adjustment 36 (52) — Balance, December 31 $ 273 $ 898 $ 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: 2019 2018 2017 Auction rate securities Balance, January 1 $ 847 $ 1,016 $ 1,144 Period transactions (264) (207) — Change in fair value 9 38 (128) Balance, December 31 $ 592 $ 847 $ 1,016 Contingent purchase consideration Balance, January 1 $ 898 $ 902 $ — Period transactions — — 902 Cash payments (632) — — Change in fair value (29) 48 — Foreign exchange adjustment 36 (52) — Balance, December 31 $ 273 $ 898 $ 902
Maturities of Debt Securities	The following table presents the effective maturity dates of debt investments as of December 31, 2019 and December 31, 2018: December 31, 2019 December 31, 2018 Book Value Fair Value Book Value Fair Value Investment maturity Held-to-maturity Less than 1 year $ 502,546 $ 502,675 $ 585,875 $ 585,573 1 through 5 years — — 3,859 3,859 Total $ 502,546 $ 502,675 $ 589,734 $ 589,432 Available-for-sale Greater than 5 years $ 592 $ 592 $ 847 $ 847

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2019
Inventory Disclosure [Abstract]
Components of Inventories	Inventories consist of the following: December 31, 2019 2018 Components and raw materials $ 200,390 $ 233,594 Work-in-process 49,620 66,498 Finished goods 130,780 103,487 Total $ 380,790 $ 403,579

Business Combinations (Tables)

Business Combinations (Tables)	12 Months Ended
	Dec. 31, 2019
Business Acquisition [Line Items]
Schedule of Pro Forma Information	The following table presents consolidated pro forma information as if the acquisition had occurred on January 1, 2017: Pro forma (Unaudited) Years ended December 31, 2018 2017 Net sales $ 1,551,373 $ 1,511,051
2018 Acquisitions
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the allocation of the assets acquired and liabilities assumed at the acquisition dates for the year ended December 31, 2018: Genesis Systems RC Total Cash and cash equivalents $ 2,847 $ 30 $ 2,877 Assets acquired excluding cash and cash equivalents and deferred tax assets 39,262 2,151 41,413 Liabilities assumed excluding deferred tax liabilities (23,506) (1,932) (25,438) Deferred tax liabilities, net — (573) (573) Intangible assets 43,700 705 44,405 Total identifiable net assets 62,303 381 62,684 Goodwill 45,684 4,072 49,756 Total purchase price $ 107,987 $ 4,453 $ 112,440
2017 Acquisitions
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed	The following table summarizes the allocation of the assets acquired and liabilities assumed at the acquisition dates for the year ended December 31, 2017: LDD ILT OptiGrate Total Cash and cash equivalents $ 1,002 $ 969 $ 3,714 $ 5,685 Assets acquired excluding cash and cash equivalents and deferred tax assets 1,346 14,353 1,351 17,050 Liabilities assumed excluding deferred tax liabilities (708) (11,669) (687) (13,064) Deferred tax liabilities, net (538) (2,004) (2,068) (4,610) Intangible assets 3,614 19,140 5,660 28,414 Total identifiable net assets 4,716 20,789 7,970 33,475 Goodwill 5,276 19,467 8,900 33,643 Total purchase price $ 9,992 $ 40,256 $ 16,870 $ 67,118

Restructuring (Tables)

Restructuring (Tables)	12 Months Ended
	Dec. 31, 2019
Restructuring and Related Activities [Abstract]
Summary of Restructuring Accrual	The following table summarizes the Company's restructuring accrual at December 31, 2019 and changes during the year ended December 31, 2019: Severance and Employee Benefit Costs Contract Cancellations Total Balance at January 1, 2019 $ — $ — $ — Charges 1,466 314 1,780 Cash payments (1,317) (275) (1,592) Balance at December 31, 2019 $ 149 $ 39 $ 188

Goodwill And Intangible Assets

Goodwill And Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill	The following table sets forth the changes in the carrying amount of goodwill for the years ended December 31, 2019 and 2018: 2019 2018 Balance at January 1 $ 100,722 $ 55,831 Adjustments to goodwill during the measurement period 448 (2,362) Goodwill arising from business combinations 19,076 47,705 Impairment losses (37,120) — Foreign exchange adjustment (1,034) (452) Balance at December 31 $ 82,092 $ 100,722
Schedule of Intangible Assets	Intangible assets, subject to amortization, consisted of the following: December 31, 2019 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Customer relationships $ 57,866 $ (11,993) $ 45,873 11 years $ 57,849 $ (6,427) $ 51,422 11 years Technology, trademark and trade name 41,297 (16,128) 25,169 7 years 41,184 (10,474) 30,710 7 years Production know-how 9,180 (7,415) 1,765 7 years 9,211 (6,212) 2,999 7 years Patents 8,036 (6,572) 1,464 8 years 8,036 (6,028) 2,008 8 years Total $ 116,379 $ (42,108) $ 74,271 $ 116,280 $ (29,141) $ 87,139
Estimated Future Amortization For Intangibles	The estimated future amortization expense for intangibles as of December 31, 2019 is as follows: 2020 2021 2022 2023 2024 Thereafter Total $ 12,059 $ 11,692 $ 10,783 $ 9,855 $ 7,515 $ 22,367 $ 74,271

Property, Plant And Equipment (

Property, Plant And Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Components Of Property Plant And Equipment	Property, plant, and equipment consist of the following: December 31, 2019 2018 Land $ 45,676 $ 41,937 Buildings 400,617 332,150 Machinery and equipment 449,783 384,259 Office furniture and fixtures 70,001 65,775 Construction-in-progress 44,201 54,454 Total property, plant and equipment 1,010,278 878,575 Accumulated depreciation (409,426) (335,507) Total property, plant and equipment — net $ 600,852 $ 543,068
Schedule of Long-Lived Assets	Long-lived assets include property, plant and equipment, related deposits on such assets and demonstration equipment. The geographic locations of the Company's long-lived assets, net, based on physical location of the assets, as of December 31, 2019 and 2018 are as follows: December 31, 2019 2018 United States $ 366,059 $ 346,343 Germany 86,881 81,218 Russia 84,471 76,359 China 8,933 9,123 Other 71,616 40,689 Total $ 617,960 $ 553,732

Accrued Expenses And Other Li_2

Accrued Expenses And Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2019
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued expenses and other liabilities consist of the following: December 31, 2019 2018 Accrued compensation $ 48,881 $ 60,107 Contract liabilities 59,531 52,606 Current portion of accrued warranty 23,114 23,106 Short-term lease liabilities 5,300 — Other 12,956 18,821 Total $ 149,782 $ 154,640

Product Warranties (Tables)

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2019
Product Warranties Disclosures [Abstract]
Schedule of Product Warranty Liability	Activity related to the warranty accrual was as follows: 2019 2018 2017 Balance at January 1 $ 51,422 $ 47,517 $ 33,978 Provision for warranty accrual 22,613 24,948 26,995 Warranty claims (24,826) (18,922) (16,250) Foreign currency translation and other (343) (2,121) 2,794 Balance at December 31 $ 48,866 $ 51,422 $ 47,517

Financing Arrangements (Tables)

Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Disclosure [Abstract]
Schedule of Financing Arrangements	The Company's borrowings under existing financing arrangements consist of the following: December 31, 2019 2018 Term debt: Long-term notes $ 41,708 $ 45,378 Less: current portion (3,740) (3,671) Total long-term debt $ 37,968 $ 41,707
Schedule of Future Principal Payments	The future principal payments for the Company’s Notes as of December 31, 2019 are as follows: 2020 $ 3,740 2021 3,810 2022 18,126 2023 16,032 Total $ 41,708

Derivative Instruments (Tables)

Derivative Instruments (Tables)	12 Months Ended
	Dec. 31, 2019
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 December 31, December 31, 2019 2018 2019 2018 $ 19,594 $ 20,781 $ 13 $ 31 1. Notional amounts represent the gross contract/notional amount of the derivative outstanding.
Derivative Gains (Losses) in the Consolidated Statements of Income Related to Interest Rate Swap Contracts	The derivative gains and losses in the consolidated financial statements for the years ended December 31, 2019, 2018 and 2017, related to the Company's current and previous interest rate swap contracts were as follows: Year Ended December 31, 2019 2018 2017 Effective portion recognized in other comprehensive income (loss), pretax: Interest rate swap $ (18) $ 15 $ (61)
Losses of Derivatives Not Designated as Hedging	Losses associated with derivative instruments not designated as hedging instruments were as follows: Year Ended December 31, Classification 2019 2018 2017 Losses recognized in income Gain (loss) on foreign exchange $ — $ (19) $ —

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Summary of Lease Assets and Liabilities	The Company's operating lease assets and lease liabilities consist of the following as of December 31, 2019: Account Classification Amount Right-of-use assets Other assets $ 23,028 Short-term lease liabilities Accrued expenses and other liabilities 5,300 Long-term lease liabilities Deferred income taxes and other long-term liabilities 20,410 Total lease liabilities $ 25,710
Schedule of Operating Lease Maturities	The table below presents the future minimum lease payments to be made under non-cancelable operating leases as of December 31, 2018: Years ending December 31, 2019 $ 6,314 2020 4,603 2021 3,358 2022 2,596 2023 2,078 Thereafter 11,340 Total $ 30,289 The table below presents the maturities of operating lease liabilities as of December 31, 2019: 2020 $ 6,004 2021 4,785 2022 3,581 2023 2,964 2024 2,136 Thereafter 10,327 Total future minimum lease payments 29,797 Less: imputed interest (4,087) Present value of lease liabilities $ 25,710 Other information relevant to the Company's operating leases consist of the following as of December 31, 2019: Weighted-average remaining lease term 9 years Weighted-average discount rate 3.58 %

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	Stock-based compensation is included in the following financial statement captions: Year Ended December 31, 2019 2018 2017 Cost of sales $ 9,249 $ 6,535 $ 5,863 Sales and marketing 3,815 2,550 2,041 Research and development 7,690 6,410 5,001 General and administrative 12,824 12,532 10,116 Total stock-based compensation 33,578 28,027 23,021 Tax benefit recognized (5,114) (6,632) (7,367) Net stock-based compensation $ 28,464 $ 21,395 $ 15,654
Summary of Stock Option Valuation Assumptions	The assumptions used in the Black-Scholes model for the calculation of compensation were as follows for the years ended December 31: 2019 2018 2017 Expected term 4.3 - 5.1 years 4.1 - 4.9 years 3.8 - 5.0 years Volatility 37% - 38% 31% - 36% 31% - 35% Risk-free rate of return 1.66% - 2.55% 2.54% - 3.01% 1.57% - 1.97% Dividend yield 0.25% 0.25% 0.25% Forfeiture rate —% —% —%
Summary of Option Activity	The following table summarizes the option activity for the years ended December 31: Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2017 2,064,253 $ 60.65 Granted 293,284 124.57 Exercised (546,931) 50.50 Forfeited (13,113) 90.81 Outstanding — December 31, 2017 1,797,493 73.95 6.02 $ 251,970 Granted 257,111 232.26 Exercised (282,720) 58.94 Forfeited (24,810) 131.36 Outstanding — December 31, 2018 1,747,074 98.93 5.80 $ 58,084 Granted 334,740 153.78 Exercised (192,533) 56.58 Forfeited (46,839) 149.64 Outstanding — December 31, 2019 1,842,442 $ 112.03 5.73 $ 85,110 Unvested — December 31, 2019 797,960 $ 149.66 7.96 $ 14,576 Exercisable — December 31, 2019 1,044,482 $ 83.29 4.02 $ 70,534
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock units ("RSU's") activity for the years ended December 31: Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2017 366,770 $ 79.72 Granted 106,764 127.29 Vested (90,385) 66.18 Canceled (4,888) 90.54 Outstanding — December 31, 2017 378,261 96.23 2.55 $ 80,997 Granted 80,254 227.45 Vested (97,997) 91.62 Canceled (9,497) 121.37 Outstanding — December 31, 2018 351,021 126.93 2.62 $ 39,767 Granted 120,090 151.94 Vested (147,606) 120.58 Canceled (16,667) 139.73 Outstanding — December 31, 2019 306,838 $ 139.09 2.57 $ 44,467
Summary of Performance Units Fair Value Assessment	The weighted-average fair value of the performance units was determined using the Monte Carlo simulation model incorporating the following weighted-average assumptions: 2019 2018 2017 Performance term 3.0 years 3.0 years 3.0 years Volatility 18% - 40% 13% - 32% 13% - 31% Risk-free rate of return 2.48% 2.41% 1.49% Dividend yield —% —% —% Weighted-average fair value per share $192.46 $284.78 $147.25
Summary of Performance Stock Unit Activity	The following table summarizes the performance stock units ("PSU's") activity for the years ended December 31: Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2017 54,505 $ 108.51 Granted 21,444 147.25 Vested — Canceled — Outstanding — December 31, 2017 75,949 119.45 1.93 $ 16,263 Granted 33,706 238.12 Vested — Canceled — Outstanding — December 31, 2017 109,655 146.96 1.77 $ 12,423 Granted 34,989 190.83 Vested (43,594) 128.54 Canceled (1,208) 228.68 Outstanding — December 31, 2019 99,842 $ 162.34 1.84 $ 14,469

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Income before Income Tax, Domestic and Foreign	Income before the impact of income taxes for the years ended December 31 consisted of the following: 2019 2018 2017 U.S. $ 59,790 $ 146,855 $ 190,480 Foreign 188,586 387,540 361,391 Total $ 248,376 $ 534,395 $ 551,871
Schedule of Components of Income Tax Expense (Benefit)	The Company's provision for income taxes for the years ended December 31 consisted of the following: 2019 2018 2017 Current: Federal $ 7,127 $ 7,274 $ 85,761 State 2,405 2,097 2,387 Foreign 74,072 125,431 93,254 Total current 83,604 134,802 181,402 Deferred: Federal (4,896) 2,497 12,459 State (1,658) 8,449 649 Foreign (8,935) (15,522) 9,773 Total deferred (15,489) (4,576) 22,881 Provision for income taxes $ 68,115 $ 130,226 $ 204,283
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of income tax expense at the U.S. federal statutory income tax rate to the recorded tax provision for the years ended December 31, were as follows: 2019 2018 2017 Tax at statutory rate $ 52,159 $ 112,223 $ 193,155 Non-U.S. rate differential — net 14,958 26,985 (25,795) State income taxes — net 2,362 3,367 3,413 Stock-based compensation - tax benefit (5,114) (13,298) (14,015) Foreign derived intangible income benefit ("FDII") (4,763) (7,930) — Global intangible low-taxed income taxed in the U.S. ("GILTI") 4,648 5,955 — Goodwill impairment 10,009 — — Effect of 2017 U.S. Tax Cuts and Jobs Act — (4,747) 48,126 Withholding tax on intercompany dividend 3,122 — 2,225 Effect of changes in enacted tax rates on deferred tax assets and liabilities (639) 8,007 1,281 Federal and state tax credits (12,173) (11,024) (9,210) Change in reserves, including interest and penalties 779 2,290 4,350 Change in valuation allowance 4,515 7,421 (51) Other — net (1,748) 977 804 Provision for income taxes $ 68,115 $ 130,226 $ 204,283
Schedule of Deferred Tax Assets and Liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, were as follows: 2019 2018 Property, plant and equipment $ (18,607) $ (22,443) Inventory provisions 23,611 12,963 Allowances and accrued liabilities 10,502 (2,599) Withholding tax on intercompany dividend (3,597) (2,225) Other tax credits 15,001 12,996 Deferred compensation 9,428 17,481 Net operating loss carryforwards 5,748 3,364 Valuation allowance (14,384) (7,910) Net deferred tax assets $ 27,702 $ 11,627
Summary of Income Tax Contingencies	The following is a tabular reconciliation of the total amounts of unrecognized tax benefits: 2019 2018 Balance at January 1 $ 11,206 $ 10,370 Change in prior period positions (1,776) (1,067) Settlement of prior period position (230) — Additions for tax positions in current period 2,000 2,726 Foreign exchange adjustments $ 216 $ (823) Balance at December 31 $ 11,416 $ 11,206
Summary of Income Tax Examinations	Open tax years by major jurisdictions are: United States 2016 - 2019 Germany 2017 - 2019 Russia 2015 - 2019

Net Income Attributable To IP_2

Net Income Attributable To IPG Photonics Corporation Per Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following table sets forth the computation of diluted net income attributable to IPG Photonics Corporation per share: Year Ended December 31, 2019 2018 2017 Net income attributable to IPG Photonics Corporation $ 180,234 $ 404,027 $ 347,614 Net income attributable to common stockholders 180,234 404,027 347,614 Weighted average shares 53,061 53,522 53,495 Dilutive effect of common stock equivalents 778 1,204 1,204 Diluted weighted average common shares 53,839 54,726 54,699 Basic net income attributable to IPG Photonics Corporation per share $ 3.40 $ 7.55 $ 6.50 Basic net income attributable to common stockholders $ 3.40 $ 7.55 $ 6.50 Diluted net income attributable to IPG Photonics Corporation per share $ 3.35 $ 7.38 $ 6.36 Diluted net income attributable to common stockholders $ 3.35 $ 7.38 $ 6.36

Selected Quarterly Financial _2

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2019
Selected Quarterly Financial Information [Abstract]
Schedule of Quarterly Financial Data	2019 First Quarter Second Quarter Third Quarter Fourth Quarter Net sales $ 315,047 $ 363,769 $ 329,138 $ 306,627 Gross profit 148,911 180,237 152,858 124,203 Net income (loss) attributable to IPG Photonics Corporation 55,159 72,272 57,253 (4,450) Net income (loss) per share, basic 1.04 1.36 1.08 (0.08) Net income (loss) per share, diluted 1.02 1.34 1.07 (0.08) 2018 First Quarter Second Quarter Third Quarter Fourth Quarter Net sales $ 359,864 $ 413,613 $ 356,346 $ 330,051 Gross profit 203,362 234,975 195,184 166,747 Net income attributable to IPG Photonics Corporation 106,334 121,617 100,517 75,559 Net income per share, basic 1.98 2.27 1.88 1.42 Net income per share, diluted 1.93 2.21 1.84 1.40

Nature Of Business And Summar_4

Nature Of Business And Summary Of Significant Accounting Policies (Narrative) (Details) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2018USD ($)	Dec. 31, 2019USD ($)numberOfCustomerssegment$ / sharescustomershares	Dec. 31, 2018USD ($)numberOfCustomers$ / sharesshares	Dec. 31, 2017USD ($)numberOfCustomers	Jan. 01, 2018USD ($)	Jan. 01, 2017USD ($)
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Bank acceptances drafts		$ 16,484	$ 27,335
Bank acceptances, weighted-average maturity period		76 days
Long-lived assets		$ 617,960	$ 553,732
Common stock, shares authorized (in shares) | shares		175,000,000	175,000,000
Common stock, par value (in dollars per share) | $ / shares		$ 0.0001	$ 0.0001
Preferred stock, shares authorized (in shares) | shares		5,000,000
Preferred stock, par value (in dollars per share) | $ / shares		$ 0.0001
Preferred stock, shares outstanding (in shares) | shares		0
Number of customers | numberOfCustomers		1	1	1
Number of largest customers | customer		5
Net sales by major customers, percentage		21.00%	26.00%	28.00%
Number of operating segments | segment		1
Deferred income tax assets		$ 31,395	$ 19,165	$ 26,976	$ 28,150
Recently adopted accounting standards					616	$ 4,223
Restricted Stock Units (RSUs)
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Vesting period		4 years
Stock option
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Vesting period		4 years
Retained Earnings
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Recently adopted accounting standards					$ 606	2,145
Additional Paid In Capital
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Recently adopted accounting standards						2,078
ASU 2018-02
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Tax Cuts and Jobs Act of 2017, reclassification from AOCI to retained earnings	$ 10
Accounting Standards Update 2016-09, Excess Tax Benefit Component
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Deferred income tax assets						3,464
Accounting Standards Update 2016-09, Excess Tax Benefit Component | Retained Earnings
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Recently adopted accounting standards						3,464
Accounting Standards Update 2016-09, Forfeiture Rate Component
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Deferred income tax assets						759
Accounting Standards Update 2016-09, Forfeiture Rate Component | Retained Earnings
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Recently adopted accounting standards						(1,319)
Accounting Standards Update 2016-09, Forfeiture Rate Component | Additional Paid In Capital
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Recently adopted accounting standards						$ 2,078
Minimum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Period for installation completion		1 year
Standard product warranty coverage period		1 year
Vesting period		1 year
Maximum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Period for installation completion		90 days
Standard product warranty coverage period		5 years
Vesting period		4 years
Intangible Assets | Minimum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible asset, useful life		1 year
Intangible Assets | Maximum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Intangible asset, useful life		13 years
Demonstration Equipment
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life		3 years
Long-lived assets		$ 7,591	7,037
Amortization		$ 4,364	$ 3,870	$ 3,769
Sales
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Percentage of net sales		9.00%	12.00%	13.00%
Accounts Receivable
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Percentage of net sales		24.00%	25.00%

Nature Of Business And Summar_5

Nature Of Business And Summary Of Significant Accounting Policies (Allowance For Doubtful Accounts) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at January 1	$ 1,731	$ 2,198	$ 2,016
Provision for bad debts, net of recoveries	677	14	51
Uncollectable accounts written off	(111)	(198)	(38)
Foreign currency translation	102	(283)	169
Balance at December 31	$ 2,399	$ 1,731	$ 2,198

Nature Of Business And Summar_6

Nature Of Business And Summary Of Significant Accounting Policies (Economic Useful Lives Of Property, Plant And Equipment) (Details)	12 Months Ended
	Dec. 31, 2019
Buildings | Minimum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life	20 years
Buildings | Maximum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life	30 years
Machinery and equipment | Minimum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life	5 years
Machinery and equipment | Maximum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life	7 years
Office furniture and fixtures | Minimum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life	5 years
Office furniture and fixtures | Maximum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment useful life	7 years

Nature Of Business And Summar_7

Nature Of Business And Summary Of Significant Accounting Policies (Components Of Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Accumulated other comprehensive loss	$ 2,402,443	$ 2,206,235	$ 2,022,322	$ 1,557,724
Unrealized gain on derivatives, tax	3	4
Foreign currency translation adjustments
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Accumulated other comprehensive loss	(147,161)	(163,155)
Unrealized gain on auction rate securities | Auction Rate Securities
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Accumulated other comprehensive loss	232	232
Unrealized gain on derivatives, net of tax of $3 and $4, respectively
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Accumulated other comprehensive loss	10	27
Accumulated Other Comprehensive (Loss) Income
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Accumulated other comprehensive loss	$ (146,919)	$ (162,896)	$ (77,344)	$ (178,583)

Nature Of Business And Summar_8

Nature Of Business And Summary Of Significant Accounting Policies (Cumulative Effect of Change to Balance Sheet) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	$ 55,876	$ 57,440	$ 57,764
Other assets	45,192	38,395	18,932
Accrued expenses and other liabilities	149,782	159,932	154,640
Deferred income taxes and other long-term liabilities	98,121	94,581	80,734
Prepaid income taxes	38,873		43,782	$ 43,741	$ 44,944
Deferred income tax assets	31,395		19,165	28,150	26,976
Customer deposits and deferred revenue (short-term)				46,508	47,324
Income taxes payable	11,053		51,161	15,810	15,773
Deferred income tax liabilities				21,496	21,362
Retained earnings	2,028,734		1,848,500	1,444,473	1,443,867
Accumulated other comprehensive loss	$ (146,919)		$ (162,896)	(77,334)	$ (77,344)
ASC 842
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets		(324)
Other assets		19,463
Accrued expenses and other liabilities		5,292
Deferred income taxes and other long-term liabilities		$ 13,847
Adoption of Standard | ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid income taxes				0
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
Accumulated other comprehensive loss				0
Adoption of Standard | ASU 2018-02
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid income taxes				0
Deferred income tax assets				0
Customer deposits and deferred revenue (short-term)				0
Income taxes payable				0
Deferred income tax liabilities				0
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
Customer deposits and deferred revenue (short-term)				0
Income taxes payable				0
Deferred income tax liabilities				0
Retained earnings				26
Accumulated other comprehensive loss				$ 0

Nature Of Business And Summar_9

Nature Of Business And Summary Of Significant Accounting Policies (Schedule of Cash, Cash Equivalents and Restricted Cash) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents	$ 680,070	$ 544,358
Restricted cash included in other assets	2,914	0
Cash, cash equivalents and restricted cash	$ 682,984	$ 544,358	$ 909,900	$ 623,855

Revenue From Contracts With C_3

Revenue From Contracts With Customers (Disaggregation of Revenue, By Application) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total	$ 306,627	$ 329,138	$ 363,769	$ 315,047	$ 330,051	$ 356,346	$ 413,613	$ 359,864	$ 1,314,581	$ 1,459,874	$ 1,408,889
Materials processing
Disaggregation of Revenue [Line Items]
Total									1,229,211	1,374,448
Other applications
Disaggregation of Revenue [Line Items]
Total									$ 85,370	$ 85,426

Revenue From Contracts With C_4

Revenue From Contracts With Customers (Disaggregation of Revenue, By Product) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total	$ 306,627	$ 329,138	$ 363,769	$ 315,047	$ 330,051	$ 356,346	$ 413,613	$ 359,864	$ 1,314,581	$ 1,459,874	$ 1,408,889
High Power Continuous Wave ("CW") Lasers
Disaggregation of Revenue [Line Items]
Total									734,745	909,726
Medium and Low Power CW Lasers
Disaggregation of Revenue [Line Items]
Total									56,625	95,764
Pulsed Lasers
Disaggregation of Revenue [Line Items]
Total									137,675	162,048
Quasi-Continuous Wave ("QCW") Lasers
Disaggregation of Revenue [Line Items]
Total									56,440	66,700
Laser and Non-Laser Systems
Disaggregation of Revenue [Line Items]
Total									141,647	59,330
Other Revenue including Amplifiers, Service, Parts, Accessories and Change in Deferred Revenue
Disaggregation of Revenue [Line Items]
Total									$ 187,449	$ 166,306

Revenue From Contracts With C_5

Revenue From Contracts With Customers (Disaggregation of Revenue, By Geography) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total	$ 306,627	$ 329,138	$ 363,769	$ 315,047	$ 330,051	$ 356,346	$ 413,613	$ 359,864	$ 1,314,581	$ 1,459,874	$ 1,408,889
North America
Disaggregation of Revenue [Line Items]
Total									280,886	202,743
Germany
Disaggregation of Revenue [Line Items]
Total									81,365	111,259
Other including Eastern Europe/CIS
Disaggregation of Revenue [Line Items]
Total									249,871	296,917
China
Disaggregation of Revenue [Line Items]
Total									491,890	629,079
Japan
Disaggregation of Revenue [Line Items]
Total									71,757	87,619
Other
Disaggregation of Revenue [Line Items]
Total									121,586	127,251
Rest of World
Disaggregation of Revenue [Line Items]
Total									$ 17,226	$ 5,006

Revenue From Contracts With C_6

Revenue From Contracts With Customers (Disaggregation of Revenue, By Timing) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Total	$ 306,627	$ 329,138	$ 363,769	$ 315,047	$ 330,051	$ 356,346	$ 413,613	$ 359,864	$ 1,314,581	$ 1,459,874	$ 1,408,889
Goods and services transferred at a point in time
Disaggregation of Revenue [Line Items]
Total									1,233,065	1,447,343
Goods and services transferred over time
Disaggregation of Revenue [Line Items]
Total									$ 81,516	$ 12,531

Revenue From Contracts With C_7

Revenue From Contracts With Customers (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue recognized that was included in the contract liability balance at the beginning of the period	$ 45,223	$ 40,944
Minimum
Disaggregation of Revenue [Line Items]
Period for installation completion	1 year

Revenue From Contracts With C_8

Revenue From Contracts With Customer (Changes in Contract Assets and Contract Liabilities) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Contract assets
Contract assets	$ 9,645	$ 10,102	$ 0
Contract assets, change	(457)	10,102
Contract liabilities
Contract liabilities - current	59,531	52,606	46,508
Contract liabilities - current, change	6,925	6,098
Contract liabilities - long-term	1,820	1,413	$ 182
Contract liabilities - long-term, change	$ 407	$ 1,231

Revenue From Contracts With C_9

Revenue From Contracts With Customers (Schedule of Remaining Performance Obligations) (Details) $ in Thousands	Dec. 31, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 35,418
Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	5,923
Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	29,495
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	32,275
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	$ 4,105
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 28,170
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	$ 2,239
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	$ 914
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 1,325
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	$ 498
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	$ 498
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 301
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	$ 301
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 87
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 18
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Revenue expected to be recognized for extended warranty agreements
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 18
Remaining performance obligations, expected timing	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01 | Revenue to be earned over time from contracts to sell robotic systems
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligations	$ 0
Remaining performance obligations, expected timing	1 year

Fair Value Measurements (Assets

Fair Value Measurements (Assets and Liabilities Measured at Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Total assets	$ 713,071	$ 771,275
Liabilities
Long-term notes	42,004	45,378
Contingent purchase consideration	273	898
Total liabilities	42,277	46,276
Money market fund deposits and term deposits
Assets
Cash equivalents	155,080	180,965
Commercial paper
Assets
Cash equivalents	54,712	78,948
U.S. Treasury and agency obligations
Assets
Cash equivalents		6,495
Short-term investments		116,800
Corporate bonds
Assets
Short-term investments	259,422	227,009
Long-term investments and other assets		3,859
Commercial paper
Assets
Short-term investments	236,752	156,321
Certificate of deposit
Assets
Short-term investments	6,501
Auction rate securities
Assets
Long-term investments and other assets	592	847
Interest rate swap
Assets
Long-term investments and other assets	12	31
Level 1
Assets
Total assets	421,003	535,128
Liabilities
Long-term notes	0	0
Contingent purchase consideration	0	0
Total liabilities	0	0
Level 1 | Money market fund deposits and term deposits
Assets
Cash equivalents	155,080	180,965
Level 1 | Commercial paper
Assets
Cash equivalents	0	0
Level 1 | U.S. Treasury and agency obligations
Assets
Cash equivalents		6,495
Short-term investments		116,800
Level 1 | Corporate bonds
Assets
Short-term investments	259,422	227,009
Long-term investments and other assets		3,859
Level 1 | Commercial paper
Assets
Short-term investments	0	0
Level 1 | Certificate of deposit
Assets
Short-term investments	6,501
Level 1 | Auction rate securities
Assets
Long-term investments and other assets	0	0
Level 1 | Interest rate swap
Assets
Long-term investments and other assets	0	0
Level 2
Assets
Total assets	291,476	235,300
Liabilities
Long-term notes	42,004	45,378
Contingent purchase consideration	0	0
Total liabilities	42,004	45,378
Level 2 | Money market fund deposits and term deposits
Assets
Cash equivalents	0	0
Level 2 | Commercial paper
Assets
Cash equivalents	54,712	78,948
Level 2 | U.S. Treasury and agency obligations
Assets
Cash equivalents		0
Short-term investments		0
Level 2 | Corporate bonds
Assets
Short-term investments	0	0
Long-term investments and other assets		0
Level 2 | Commercial paper
Assets
Short-term investments	236,752	156,321
Level 2 | Certificate of deposit
Assets
Short-term investments	0
Level 2 | Auction rate securities
Assets
Long-term investments and other assets	0	0
Level 2 | Interest rate swap
Assets
Long-term investments and other assets	12	31
Level 3
Assets
Total assets	592	847
Liabilities
Long-term notes	0	0
Contingent purchase consideration	273	898
Total liabilities	273	898
Level 3 | Money market fund deposits and term deposits
Assets
Cash equivalents	0	0
Level 3 | Commercial paper
Assets
Cash equivalents	0	0
Level 3 | U.S. Treasury and agency obligations
Assets
Cash equivalents		0
Short-term investments		0
Level 3 | Corporate bonds
Assets
Short-term investments	0	0
Long-term investments and other assets		0
Level 3 | Commercial paper
Assets
Short-term investments	0	0
Level 3 | Certificate of deposit
Assets
Short-term investments	0
Level 3 | Auction rate securities
Assets
Long-term investments and other assets	592	847
Level 3 | Interest rate swap
Assets
Long-term investments and other assets	$ 0	$ 0

Fair Value Measurements (Narrat

Fair Value Measurements (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	$ 713,071,000	$ 771,275,000
Held-to-maturity impairment	0	0
Available-for-sale securities impairment	0	0
Held-to-maturity securities | Short-term investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	502,675,000	500,130,000
Unrealized gain (loss)	129,000	(302,000)
Held-to-maturity securities | Long-term investment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value	0	3,859,000
Available-for-sale securities | Auction rate securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cost basis	$ 592,000	$ 847,000

Fair Value Measurements (Fair V

Fair Value Measurements (Fair Value of Auction Rate Securities and Contingent Purchase Consideration (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Auction rate securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, January 1	$ 847	$ 1,016	$ 1,144
Period transactions	(264)	(207)	0
Change in fair value	9	38	(128)
Balance, December 31	592	847	1,016
Contingent purchase consideration
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, January 1	898	902	0
Period transactions	0	0	902
Cash payments	(632)	0	0
Change in fair value	(29)	48	0
Foreign exchange adjustment	36	(52)	0
Balance, December 31	$ 273	$ 898	$ 902

Fair Value Measurements (Schedu

Fair Value Measurements (Schedule of Effective Maturity Dates of Held To Maturity Investments) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Held-to-maturity, Maturity, Amortized Cost, Net [Abstract]
Held-to-maturity Debt Maturities, Less than 1 year, Book Value	$ 502,546	$ 585,875
Held-to-maturity Debt Maturities, 1 through 5 years, Book Value	0	3,859
Held-to-maturity Debt Maturities, Total Book Value	502,546	589,734
Held-to-maturity Debt Maturities, Less than 1 year, Fair Value	502,675	585,573
Held-to-maturity Debt Maturities, 1 through 5 years, Fair Value	0	3,859
Held-to-maturity Debt Maturities, Total Fair Value	502,675	589,432
Available-for-sale Securities, Debt Maturities [Abstract]
Available-for-sale maturity, greater than 5 years, book value	592	847
Available-for-sale maturities, greater than 5 years, fair value	$ 592	$ 847

Inventories (Components Of Inve

Inventories (Components Of Inventories) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Components and raw materials	$ 200,390	$ 233,594
Work-in-process	49,620	66,498
Finished goods	130,780	103,487
Total	$ 380,790	$ 403,579

Inventories (Narrative) (Detail

Inventories (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Inventory Disclosure [Abstract]
Inventory provisions	$ 38,902	$ 12,981	$ 16,946

Business Combinations (Narrativ

Business Combinations (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended							12 Months Ended
	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2019	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Restricted cash	$ 2,914		$ 0					$ 2,914	$ 0
Adjustments to goodwill during the measurement period								448	(2,362)
Goodwill acquired								19,076	47,705
Goodwill	82,092		$ 100,722		$ 55,831			82,092	$ 100,722
SND
Acquired Finite-Lived Intangible Assets [Line Items]
Consideration transferred		$ 19,560
Restricted cash	2,914	2,934						2,914
Decrease in intangible assets	9,650
Adjustments to goodwill during the measurement period	9,650
Decrease in amortization expense	848
Decrease in accumulated amortization	848
Goodwill acquired		19,076
SND | Licensing Agreements
Acquired Finite-Lived Intangible Assets [Line Items]
Restricted cash	$ 1,861	1,956						$ 1,861
Genesis Systems
Acquired Finite-Lived Intangible Assets [Line Items]
Ownership percentage acquired			100.00%						100.00%
Purchase price			$ 107,987						$ 107,987
Working capital adjustment		$ 448
Escrow deposit			1,350						1,350
Goodwill			45,684						$ 45,684
Genesis Systems | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 32,350
Acquired intangible asset, useful life			11 years
Genesis Systems | Technology, trademark and trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired			$ 11,350
Acquired intangible asset, useful life			6 years
RC
Acquired Finite-Lived Intangible Assets [Line Items]
Ownership percentage acquired				100.00%
Purchase price				$ 4,453
Goodwill				4,072
RC | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 111
Acquired intangible asset, useful life				1 year
RC | Technology, trademark and trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired				$ 594
Acquired intangible asset, useful life				10 years
LDD
Acquired Finite-Lived Intangible Assets [Line Items]
Ownership percentage acquired					100.00%
Purchase price					$ 9,992
Goodwill					5,276
LDD | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired					$ 1,006
Acquired intangible asset, useful life					6 years
LDD | Technology, trademark and trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired					$ 2,608
Acquired intangible asset, useful life					6 years
ILT
Acquired Finite-Lived Intangible Assets [Line Items]
Ownership percentage acquired						100.00%
Purchase price						$ 40,256
Goodwill						19,467
ILT | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired						$ 11,660
Acquired intangible asset, useful life						13 years
ILT | Technology, trademark and trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired						$ 7,480
Acquired intangible asset, useful life						8 years
OptiGrate
Acquired Finite-Lived Intangible Assets [Line Items]
Ownership percentage acquired							100.00%
Purchase price							$ 16,870
Goodwill							8,900
OptiGrate | Customer relationships
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired							$ 1,010
Acquired intangible asset, useful life							4 years
OptiGrate | Technology, trademark and trade name
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired							$ 4,650
Acquired intangible asset, useful life							9 years

Business Combinations (Assets A

Business Combinations (Assets Acquired and Liabilities Assumed) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017
Business Acquisition [Line Items]
Goodwill	$ 82,092	$ 100,722		$ 55,831
Genesis Systems
Business Acquisition [Line Items]
Cash and cash equivalents		2,847
Assets acquired excluding cash and cash equivalents and deferred tax assets		39,262
Liabilities assumed excluding deferred tax liabilities		(23,506)
Deferred tax liabilities, net		0
Intangible assets		43,700
Total identifiable net assets		62,303
Goodwill		45,684
Total purchase price		107,987
RC
Business Acquisition [Line Items]
Cash and cash equivalents			$ 30
Assets acquired excluding cash and cash equivalents and deferred tax assets			2,151
Liabilities assumed excluding deferred tax liabilities			(1,932)
Deferred tax liabilities, net			(573)
Intangible assets			705
Total identifiable net assets			381
Goodwill			4,072
Total purchase price			$ 4,453
GmbH RC and Genesis
Business Acquisition [Line Items]
Cash and cash equivalents		2,877
Assets acquired excluding cash and cash equivalents and deferred tax assets		41,413
Liabilities assumed excluding deferred tax liabilities		(25,438)
Deferred tax liabilities, net		(573)
Intangible assets		44,405
Total identifiable net assets		62,684
Goodwill		49,756
Total purchase price		$ 112,440
LDD
Business Acquisition [Line Items]
Cash and cash equivalents				1,002
Assets acquired excluding cash and cash equivalents and deferred tax assets				1,346
Liabilities assumed excluding deferred tax liabilities				(708)
Deferred tax liabilities, net				(538)
Intangible assets				3,614
Total identifiable net assets				4,716
Goodwill				5,276
Total purchase price				9,992
ILT
Business Acquisition [Line Items]
Cash and cash equivalents					$ 969
Assets acquired excluding cash and cash equivalents and deferred tax assets					14,353
Liabilities assumed excluding deferred tax liabilities					(11,669)
Deferred tax liabilities, net					(2,004)
Intangible assets					19,140
Total identifiable net assets					20,789
Goodwill					19,467
Total purchase price					$ 40,256
OptiGrate
Business Acquisition [Line Items]
Cash and cash equivalents						$ 3,714
Assets acquired excluding cash and cash equivalents and deferred tax assets						1,351
Liabilities assumed excluding deferred tax liabilities						(687)
Deferred tax liabilities, net						(2,068)
Intangible assets						5,660
Total identifiable net assets						7,970
Goodwill						8,900
Total purchase price						$ 16,870
LDD, ILT, And OptiGrate
Business Acquisition [Line Items]
Cash and cash equivalents				5,685
Assets acquired excluding cash and cash equivalents and deferred tax assets				17,050
Liabilities assumed excluding deferred tax liabilities				(13,064)
Deferred tax liabilities, net				(4,610)
Intangible assets				28,414
Total identifiable net assets				33,475
Goodwill				33,643
Total purchase price				$ 67,118

Business Combinations (Pro Form

Business Combinations (Pro Forma Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Genesis Systems
Business Acquisition [Line Items]
Net sales	$ 1,551,373	$ 1,511,051

Restructuring (Narrative) (Deta

Restructuring (Narrative) (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Restructuring Cost and Reserve [Line Items]
Charges		$ 1,780
Goodwill impairment		37,120	$ 0	$ 0
SND Plan
Restructuring Cost and Reserve [Line Items]
Charges	$ 21,163
Goodwill impairment	17,795
Other Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Charges		3,762
Severance and Employee Benefit Costs
Restructuring Cost and Reserve [Line Items]
Charges		1,466
Severance and Employee Benefit Costs | SND Plan
Restructuring Cost and Reserve [Line Items]
Charges	202
Severance and Employee Benefit Costs | Other Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Charges		1,264
Non-cash asset related costs | SND Plan
Restructuring Cost and Reserve [Line Items]
Charges	2,852
Non-cash asset related costs | Other Restructuring Plans
Restructuring Cost and Reserve [Line Items]
Charges		2,498
Contract Cancellations
Restructuring Cost and Reserve [Line Items]
Charges		$ 314
Contract Cancellations | SND Plan
Restructuring Cost and Reserve [Line Items]
Charges	$ 314

Restructuring (Summary of Restr

Restructuring (Summary of Restructuring Accrual) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	$ 0
Charges	1,780
Cash payments	(1,592)
Balance at December 31, 2019	188
Severance and Employee Benefit Costs
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	0
Charges	1,466
Cash payments	(1,317)
Balance at December 31, 2019	149
Contract Cancellations
Restructuring Reserve [Roll Forward]
Balance at January 1, 2019	0
Charges	314
Cash payments	(275)
Balance at December 31, 2019	$ 39

Goodwill And Intangible Asset_2

Goodwill And Intangible Assets (Changes In The Carrying Amount Of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Balance at January 1	$ 100,722	$ 55,831
Adjustments to goodwill during the measurement period	448	(2,362)
Goodwill arising from business combinations	19,076	47,705
Impairment losses	(37,120)	0	$ 0
Foreign exchange adjustment	(1,034)	(452)
Balance at December 31	$ 82,092	$ 100,722	$ 55,831

Goodwill And Intangible Asset_3

Goodwill And Intangible Assets (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Line Items]
Goodwill impairment	$ 37,120	$ 0	$ 0
Amortization expense for intangible assets	12,945	$ 8,170	$ 5,899
Transceivers
Goodwill [Line Items]
Goodwill impairment	19,325
Submarine Telecommunications
Goodwill [Line Items]
Goodwill impairment	$ 17,795

Goodwill And Intangible Asset_4

Goodwill And Intangible Assets (Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 116,379	$ 116,280
Accumulated Amortization	(42,108)	(29,141)
Net Carrying Amount	74,271	87,139
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	57,866	57,849
Accumulated Amortization	(11,993)	(6,427)
Net Carrying Amount	$ 45,873	$ 51,422
Intangible asset, useful life	11 years	11 years
Technology, trademark and trade name
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 41,297	$ 41,184
Accumulated Amortization	(16,128)	(10,474)
Net Carrying Amount	$ 25,169	$ 30,710
Intangible asset, useful life	7 years	7 years
Production know-how
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 9,180	$ 9,211
Accumulated Amortization	(7,415)	(6,212)
Net Carrying Amount	$ 1,765	$ 2,999
Intangible asset, useful life	7 years	7 years
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,036	$ 8,036
Accumulated Amortization	(6,572)	(6,028)
Net Carrying Amount	$ 1,464	$ 2,008
Intangible asset, useful life	8 years	8 years

Goodwill And Intangible Asset_5

Goodwill And Intangible Assets (Estimated Future Amortization Expense For Intangibles) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2020	$ 12,059
2021	11,692
2022	10,783
2023	9,855
2024	7,515
Thereafter	22,367
Net Carrying Amount	$ 74,271	$ 87,139

Property, Plant And Equipment_2

Property, Plant And Equipment (Components Of Property, Plant, And Equipment) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 1,010,278	$ 878,575
Accumulated depreciation	(409,426)	(335,507)
Total property, plant and equipment — net	600,852	543,068
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	45,676	41,937
Buildings
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	400,617	332,150
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	449,783	384,259
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	70,001	65,775
Construction-in-progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 44,201	$ 54,454

Property, Plant And Equipment_3

Property, Plant And Equipment (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Abstract]
Depreciation	$ 78,959	$ 68,231	$ 54,900

Property, Plant And Equipment_4

Property, Plant And Equipment (Long-Lived Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Long-lived assets	$ 617,960	$ 553,732
United States
Property, Plant and Equipment [Line Items]
Long-lived assets	366,059	346,343
Germany
Property, Plant and Equipment [Line Items]
Long-lived assets	86,881	81,218
Russia
Property, Plant and Equipment [Line Items]
Long-lived assets	84,471	76,359
China
Property, Plant and Equipment [Line Items]
Long-lived assets	8,933	9,123
Other
Property, Plant and Equipment [Line Items]
Long-lived assets	$ 71,616	$ 40,689

Accrued Expenses And Other Li_3

Accrued Expenses And Other Liabilities (Components Of Accrued Expenses And Other Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
Payables and Accruals [Abstract]
Accrued compensation	$ 48,881		$ 60,107
Contract liabilities	59,531		52,606	$ 46,508
Current portion of accrued warranty	23,114		23,106
Short-term lease liabilities	5,300		0
Other	12,956		18,821
Total	$ 149,782	$ 159,932	$ 154,640

Product Warranties (Summary of

Product Warranties (Summary of Product Warranty Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Product Warranties Disclosures [Abstract]
Balance at January 1	$ 51,422	$ 47,517	$ 33,978
Provision for warranty accrual	22,613	24,948	26,995
Warranty claims	(24,826)	(18,922)	(16,250)
Foreign currency translation and other	(343)	(2,121)	2,794
Balance at December 31	$ 48,866	$ 51,422	$ 47,517

Product Warranties (Narrative)

Product Warranties (Narrative) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Product Warranties Disclosures [Abstract]
Current portion of accrued warranty	$ 23,114	$ 23,106
Noncurrent portion of accrued warranty	$ 25,752	$ 28,316

Financing Arrangements (Borrowi

Financing Arrangements (Borrowings Under Existing Financing Arrangements) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Long-term notes	$ 41,708	$ 45,378
Less: current portion	(3,740)	(3,671)
Total long-term debt	$ 37,968	$ 41,707

Financing Arrangements (Narrati

Financing Arrangements (Narrative) (Details)	12 Months Ended
	Dec. 31, 2019USD ($)credit_line	May 31, 2023USD ($)	Jul. 31, 2022USD ($)	Dec. 31, 2019EUR (€)credit_line	Dec. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Long-term debt	$ 41,708,000				$ 45,378,000
Current portion of long-term debt	3,740,000				3,671,000
Long-Term Note
Line of Credit Facility [Line Items]
Current portion of long-term debt	3,740,000				$ 3,671,000
Unsecured Debt
Line of Credit Facility [Line Items]
Notes payable	19,594,000
Notes payable, current	1,188,000
Unsecured Debt | Scenario, Forecast
Line of Credit Facility [Line Items]
Notes payable		$ 15,438,000
Secured Debt
Line of Credit Facility [Line Items]
Notes payable	22,114,000
Notes payable, current	$ 2,552,000
Interest rate	2.74%			2.74%
Secured Debt | Scenario, Forecast
Line of Credit Facility [Line Items]
Notes payable			$ 15,375,000
London Interbank Offered Rate (LIBOR) | Unsecured Debt
Line of Credit Facility [Line Items]
Spread on variable rate	1.20%
U S Line Of Credit
Line of Credit Facility [Line Items]
Line of credit	$ 0
Guarantees issued	$ 1,426,000
US Long Term Note
Line of Credit Facility [Line Items]
Debt service coverage ratio	1.5
Maximum indebtedness against EBITDA	3
US Long Term Note | Minimum
Line of Credit Facility [Line Items]
Covenant, debt service coverage	$ 50,000,000
US Long Term Note | Maximum
Line of Credit Facility [Line Items]
Covenant, debt service coverage	250,000,000
Euro Line Of Credit
Line of Credit Facility [Line Items]
Line of credit	0
Guarantees issued	1,422,000
Other European Facilities
Line of Credit Facility [Line Items]
Borrowing capacity	$ 2,243,000			€ 2,000,000
Number of credit lines | credit_line	2			2
Letter of Credit | U S Line Of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 50,000,000
Remaining borrowing capacity	$ 48,574,000
Letter of Credit | U S Line Of Credit | Minimum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Spread on variable rate	0.80%
Letter of Credit | U S Line Of Credit | Maximum | London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Spread on variable rate	1.20%
Letter of Credit | Euro Line Of Credit
Line of Credit Facility [Line Items]
Borrowing capacity	$ 56,074,000			€ 50,000,000
Remaining borrowing capacity	54,652,000
Letter of Credit | Other European Facilities
Line of Credit Facility [Line Items]
Line of credit	0
Remaining borrowing capacity	$ 2,243,000
Interest rate swap | Unsecured Debt
Line of Credit Facility [Line Items]
Fixed interest rate	2.85%			2.85%

Financing Arrangements (Future

Financing Arrangements (Future Principal Payments) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
2020	$ 3,740
2021	3,810
2022	18,126
2023	16,032
Long-term notes	$ 41,708	$ 45,378

Derivative Instruments (Fair Va

Derivative Instruments (Fair Value) (Details) - Designated as cash flow hedge - Interest rate swap - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Notional amounts	$ 19,594	$ 20,781
Other Assets
Derivatives, Fair Value [Line Items]
Derivative asset, fair value	$ 13	$ 31

Derivative Instruments (Derivat

Derivative Instruments (Derivative Gains (Losses) in the Consolidated Statements of Income Related to Interest Rate Swap Contracts) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Designated as cash flow hedge | Interest rate swap
Effective portion recognized in other comprehensive income (loss), pretax:
Effective portion recognized in other comprehensive income (loss), pretax	$ (18)	$ 15	$ (61)

Derivative Instruments (Losses

Derivative Instruments (Losses recognized in income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Losses recognized in income	$ 0	$ (19)	$ 0

Leases (Narrative) (Details)

Leases (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Commitments [Line Items]
Rent expense	$ 8,800
Rent expense		$ 6,175	$ 8,095
Operating lease payments	$ 6,802
Minimum
Other Commitments [Line Items]
Remaining lease term	1 year
Maximum
Other Commitments [Line Items]
Remaining lease term	46 years

Leases (Lease Assets and Liabil

Leases (Lease Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Leases [Abstract]
Right-of-use assets	$ 23,028
Short-term lease liabilities	5,300	$ 0
Long-term lease liabilities	20,410
Total lease liabilities	$ 25,710

Leases (Future Minimum Payments

Leases (Future Minimum Payments) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]
2019		$ 6,314
2020		4,603
2021		3,358
2022		2,596
2023		2,078
Thereafter		11,340
Total		$ 30,289
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2020	$ 6,004
2021	4,785
2022	3,581
2023	2,964
2024	2,136
Thereafter	10,327
Total future minimum lease payments	29,797
Less: imputed interest	(4,087)
Present value of lease liabilities	$ 25,710
Lease, Cost [Abstract]
Weighted-average remaining lease term	9 years
Weighted-average discount rate	3.58%

Commitments And Contingencies (

Commitments And Contingencies (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 21, 2020	Dec. 31, 2018
Other Commitments [Line Items]
Purchase obligations	$ 53,922,000		$ 114,396,000
Management
Other Commitments [Line Items]
Duration of employment agreement	3 years
Subsequent Event
Other Commitments [Line Items]
Estimated litigation liability		$ 0

Stock-Based Compensation (Compo

Stock-Based Compensation (Components Of Stock Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 33,578	$ 28,027	$ 23,021
Tax benefit recognized	(5,114)	(6,632)	(7,367)
Net stock-based compensation	28,464	21,395	15,654
Cost of sales
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	9,249	6,535	5,863
Sales and marketing
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	3,815	2,550	2,041
Research and development
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	7,690	6,410	5,001
General and administrative
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total stock-based compensation	$ 12,824	$ 12,532	$ 10,116

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Termination period	2 years
Intrinsic value of options exercised	$ 17,891	$ 51,266	$ 50,131
Shares granted, weighted average grant date fair value (in dollars per share)	$ 53.52	$ 71.06	$ 38.01
Compensation cost not yet recognized	$ 25,517
Compensation cost not yet recognized, period of recognition	2 years 7 months 6 days
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Compensation cost not yet recognized	$ 26,231
Compensation cost not yet recognized, period of recognition	2 years 7 months 6 days
Aggregate fair value of awards vested	$ 17,799
Intrinsic value of RSUs exercised	$ 22,638	$ 22,978	$ 11,684
Weighted-average grant-date fair value, granted (in dollars per share)	$ 151.94	$ 227.45	$ 127.29
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Right to receive common stock, shares (in shares)	1
Compensation cost not yet recognized	$ 5,833
Compensation cost not yet recognized, period of recognition	1 year 9 months 18 days
Aggregate fair value of awards vested	$ 5,604
Intrinsic value of RSUs exercised	$ 6,830
Weighted-average grant-date fair value, granted (in dollars per share)	$ 190.83	$ 238.12	$ 147.25
Target goal, percentage	100.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 year
Minimum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award units earned, percentage	0.00%
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	4 years
Expiration period	10 years
Maximum | Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award units earned, percentage	200.00%
2006 Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance (in shares)	10,363,465
Shares available for grant (in shares)	3,172,643

Stock-Based Compensation (Weigh

Stock-Based Compensation (Weighted-Average Assumptions-Options) (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	37.00%	31.00%	31.00%
Volatility, maximum	38.00%	36.00%	35.00%
Risk-free rate of return, minimum	1.66%	2.54%	1.57%
Risk-free rate of return, maximum	2.55%	3.01%	1.97%
Dividend yield	0.25%	0.25%	0.25%
Forfeiture rate	0.00%	0.00%	0.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	4 years 3 months 18 days	4 years 1 month 6 days	3 years 9 months 18 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	5 years 1 month 6 days	4 years 10 months 24 days	5 years

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary Of Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Options
Outstanding (in shares)	1,747,074	1,797,493	2,064,253
Granted (in shares)	334,740	257,111	293,284
Exercised (in shares)	(192,533)	(282,720)	(546,931)
Forfeited (in shares)	(46,839)	(24,810)	(13,113)
Outstanding (in shares)	1,842,442	1,747,074	1,797,493
Unvested (in shares)	797,960
Exercisable (in shares)	1,044,482
Weighted- Average Exercise Price
Outstanding (in dollars per share)	$ 98.93	$ 73.95	$ 60.65
Granted (in dollars per share)	153.78	232.26	124.57
Exercised (in dollars per share)	56.58	58.94	50.50
Forfeited (in dollars per share)	149.64	131.36	90.81
Outstanding (in dollars per share)	112.03	$ 98.93	$ 73.95
Unvested (in dollars per share)	149.66
Exercisable (in dollars per share)	$ 83.29
Additional Disclosures
Outstanding, Weighted-average remaining contractual life	5 years 8 months 23 days	5 years 9 months 18 days	6 years 7 days
Unvested, Weighted-average remaining contractual life	7 years 11 months 15 days
Exercisable, Weighted-average remaining contractual life	4 years 7 days
Outstanding, Aggregate intrinsic value	$ 85,110	$ 58,084	$ 251,970
Unvested, Aggregate intrinsic value	14,576
Exercisable, Aggregate intrinsic value	$ 70,534

Stock-Based Compensation (Sum_2

Stock-Based Compensation (Summary of Restricted Stock Unit Activity) (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Outstanding, beginning balance (in shares)	351,021	378,261	366,770
Granted (in shares)	120,090	80,254	106,764
Vested (in shares)	(147,606)	(97,997)	(90,385)
Canceled (in shares)	(16,667)	(9,497)	(4,888)
Outstanding, ending balance (in shares)	306,838	351,021	378,261
Weighted-Average Grant-Date Fair Value
Weighted-Average Grant-Date Fair Value, Outstanding, beginning balance (in dollars per share)	$ 126.93	$ 96.23	$ 79.72
Weighted-Average Grant-Date Fair Value, Granted (in dollars per share)	151.94	227.45	127.29
Weighted-Average Grant-Date Fair Value, Vested (in dollars per share)	120.58	91.62	66.18
Weighted-Average Grant-Date Fair Value, Canceled (in dollars per share)	139.73	121.37	90.54
Weighted-Average Grant-Date Fair Value, Outstanding, ending balance (in dollars per share)	$ 139.09	$ 126.93	$ 96.23
Additional Disclosures
Weighted-Average Remaining Contractual Life, Outstanding	2 years 6 months 25 days	2 years 7 months 13 days	2 years 6 months 18 days
Aggregate Intrinsic Value, Outstanding	$ 44,467	$ 39,767	$ 80,997

Stock-Based Compensation (Wei_2

Stock-Based Compensation (Weighted-Average Assumptions-PSUs) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	37.00%	31.00%	31.00%
Volatility, maximum	38.00%	36.00%	35.00%
Dividend yield	0.25%	0.25%	0.25%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	3 years	3 years	3 years
Volatility, minimum	18.00%	13.00%	13.00%
Volatility, maximum	40.00%	32.00%	31.00%
Risk-free rate of return	2.48%	2.41%	1.49%
Dividend yield	0.00%	0.00%	0.00%
Weighted-average fair value per share (in dollars per share)	$ 192.46	$ 284.78	$ 147.25

Stock-Based Compensation (Sum_3

Stock-Based Compensation (Summary of Performance Stock Unit Activity) (Details) - Performance Shares - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Shares
Outstanding, beginning balance (in shares)	109,655	75,949	54,505
Granted (in shares)	34,989	33,706	21,444
Vested (in shares)	(43,594)	0	0
Canceled (in shares)	(1,208)	0	0
Outstanding, ending balance (in shares)	99,842	109,655	75,949
Weighted-Average Grant-Date Fair Value
Weighted-Average Grant-Date Fair Value, Outstanding, beginning balance (in dollars per share)	$ 146.96	$ 119.45	$ 108.51
Weighted-Average Grant-Date Fair Value, Granted (in dollars per share)	190.83	238.12	147.25
Weighted-Average Grant-Date Fair Value, Vested (in dollars per share)	128.54
Weighted-Average Grant-Date Fair Value, Canceled (in dollars per share)	228.68
Weighted-Average Grant-Date Fair Value, Outstanding, ending balance (in dollars per share)	$ 162.34	$ 146.96	$ 119.45
Additional Disclosures
Weighted-Average Remaining Contractual Life, Outstanding	1 year 10 months 2 days	1 year 9 months 7 days	1 year 11 months 4 days
Aggregate Intrinsic Value, Outstanding	$ 14,469	$ 12,423	$ 16,263

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Compensation expense	$ 6,005	$ 4,261	$ 3,363
Employee Stock
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Discount form market price	15.00%
Period for discount from market price	6 months
Maximum employee subscription rate	10.00%
Compensation expense for employee stock purchase plan	$ 2,254	$ 925	$ 967
Shares available for grant (in shares)	335,487

Income Taxes (Income Before Imp

Income Taxes (Income Before Impact Of Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
U.S.	$ 59,790	$ 146,855	$ 190,480
Foreign	188,586	387,540	361,391
Income before provision for income taxes	$ 248,376	$ 534,395	$ 551,871

Income Taxes (Provision For Inc

Income Taxes (Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Current:
Federal	$ 7,127	$ 7,274	$ 85,761
State	2,405	2,097	2,387
Foreign	74,072	125,431	93,254
Total current	83,604	134,802	181,402
Deferred:
Federal	(4,896)	2,497	12,459
State	(1,658)	8,449	649
Foreign	(8,935)	(15,522)	9,773
Total deferred	(15,489)	(4,576)	22,881
Provision for income taxes	$ 68,115	$ 130,226	$ 204,283

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of Effective Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax at statutory rate	$ 52,159	$ 112,223	$ 193,155
Non-U.S. rate differential — net	14,958	26,985	(25,795)
State income taxes — net	2,362	3,367	3,413
Stock-based compensation - tax benefit	(5,114)	(13,298)	(14,015)
Foreign derived intangible income benefit ("FDII")	(4,763)	(7,930)	0
Global intangible low-taxed income taxed in the U.S. ("GILTI")	4,648	5,955	0
Goodwill impairment	10,009	0	0
Effect of 2017 U.S. Tax Cuts and Jobs Act	0	(4,747)	48,126
Withholding tax on intercompany dividend	3,122	0	2,225
Effect of changes in enacted tax rates on deferred tax assets and liabilities	(639)	8,007	1,281
Federal and state tax credits	(12,173)	(11,024)	(9,210)
Change in reserves, including interest and penalties	779	2,290	4,350
Change in valuation allowance	4,515	7,421	(51)
Other — net	(1,748)	977	804
Provision for income taxes	$ 68,115	$ 130,226	$ 204,283

Income Taxes (Deferred Tax Asse

Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Property, plant and equipment	$ (18,607)	$ (22,443)
Inventory provisions	23,611	12,963
Allowances and accrued liabilities	10,502
Allowances and accrued liabilities		(2,599)
Withholding tax on intercompany dividend	(3,597)	(2,225)
Other tax credits	15,001	12,996
Deferred compensation	9,428	17,481
Net operating loss carryforwards	5,748	3,364
Valuation allowance	(14,384)	(7,910)
Net deferred tax assets	$ 27,702	$ 11,627

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) € in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2019EUR (€)	Dec. 31, 2016USD ($)
Tax Credit Carryforward [Line Items]
Transition tax		$ 43,379,000
Transition tax for foreign earnings, provisional income tax expense				$ 48,126,000
Increase (decrease) in transition tax	$ (4,747,000)
Transition tax, noncurrent		30,263,000	$ 30,263,000
Decrease in tax expense due to change in tax rate, excluding prepaid taxes			1,422,000
Transition tax for accumulated foreign earnings				(1,281,000)
Increase in income tax expense	$ 141,000
Deferred tax liabilities, withholding and dividend tax, foreign		(3,597,000)	(2,225,000)
Undistributed earnings of foreign subsidiaries		1,078,879,000	930,993,000		€ 150,000
Penalties and interest expense		543,000	631,000	$ 121,000
Accrued penalties and interest		1,672,000	1,419,000
Menara Networks
Tax Credit Carryforward [Line Items]
Operating loss carry-forwards		8,953,000	12,577,000			$ 22,242,000
Operating loss carry-forwards, valuation allowance		0
State
Tax Credit Carryforward [Line Items]
Transition tax		130,000
Foreign
Tax Credit Carryforward [Line Items]
Operating loss carry-forwards		13,218,000	2,888,000
Operating loss carry-forwards, valuation allowance		3,753,000	474,000
State
Tax Credit Carryforward [Line Items]
Tax credit carry-forwards		15,003,000	11,801,000
Tax credit carryforward, valuation allowance		$ 10,632,000	$ 7,439,000

Income Taxes (Reconciliation _2

Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 11,206	$ 10,370
Change in prior period positions	(1,776)	(1,067)
Settlement of prior period position	(230)	0
Additions for tax positions in current period	2,000	2,726
Foreign exchange adjustments	216
Foreign exchange adjustments		(823)
Balance at December 31	$ 11,416	$ 11,206

Income Taxes (Open Tax Years By

Income Taxes (Open Tax Years By Major Jurisdictions) (Details)	12 Months Ended
	Dec. 31, 2019
Minimum | United States
Income Tax Contingency [Line Items]
Open tax year	2016
Minimum | Germany
Income Tax Contingency [Line Items]
Open tax year	2017
Minimum | Russia
Income Tax Contingency [Line Items]
Open tax year	2015
Maximum | United States
Income Tax Contingency [Line Items]
Open tax year	2019
Maximum | Germany
Income Tax Contingency [Line Items]
Open tax year	2019
Maximum | Russia
Income Tax Contingency [Line Items]
Open tax year	2019

Net Income Attributable To IP_3

Net Income Attributable To IPG Photonics Corporation Per Share (Computation Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings Per Share [Abstract]
Net income (loss) attributable to IPG Photonics Corporation	$ (4,450)	$ 57,253	$ 72,272	$ 55,159	$ 75,559	$ 100,517	$ 121,617	$ 106,334	$ 180,234	$ 404,027	$ 347,614
Net income attributable to common stockholders									$ 180,234	$ 404,027	$ 347,614
Weighted average shares (in shares)									53,061	53,522	53,495
Dilutive effect of common stock equivalents (in shares)									778	1,204	1,204
Diluted weighted average common shares (in shares)									53,839	54,726	54,699
Basic net income attributable to IPG Phontonics Corporation per share (in dollars per share)									$ 3.40	$ 7.55	$ 6.50
Basic net income attributable to common stockholders (in dollars per share)	$ (0.08)	$ 1.08	$ 1.36	$ 1.04	$ 1.42	$ 1.88	$ 2.27	$ 1.98	3.40	7.55	6.50
Diluted net income attributable to IPG Photonics Corporation per share (in dollars per share)									3.35	7.38	6.36
Diluted net income attributable to common stockholders (in dollars per share)	$ (0.08)	$ 1.07	$ 1.34	$ 1.02	$ 1.40	$ 1.84	$ 2.21	$ 1.93	$ 3.35	$ 7.38	$ 6.36

Net Income Attributable To IP_4

Net Income Attributable To IPG Photonics Corporation Per Share (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Feb. 12, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	670,600	279,700	182,900
Shares repurchased (in shares)	301,262	1,051,825	275,495
Shares repurchased, average cost per share (in dollars per share)	$ 135.21	$ 167.39	$ 145.15
Decrease in weighted average number of treasury shares (in shares)	97,054	363,936	160,440
Share Repurchase Program, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Authorized amount				$ 125,000,000
Remaining authorized repurchase amount	$ 84,268,000
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	58,700	60,500	11,900
Performance Shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	40,900	14,900	0
Stock option
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive shares (in shares)	571,000	204,300	171,000

Related-Party Transactions (Nar

Related-Party Transactions (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Jul. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Related Party Transaction [Line Items]
Rent expense		$ 8,800,000
Chief Executive Officer | Aircraft, Leased | Air Transportation Equipment
Related Party Transaction [Line Items]
Percentage of property under operating lease	25.00%
Related party transaction amount		924,000	$ 925,000	$ 753,000
Chief Executive Officer | Aircraft, 2017 Lease | Air Transportation Equipment
Related Party Transaction [Line Items]
Rent expense		925,000
Chief Executive Officer | Aircraft, 2014 Lease | Air Transportation Equipment
Related Party Transaction [Line Items]
Rent expense					$ 651,000
Director | Purchased Parts and Services from Company which Independent Director is Executive Officer
Related Party Transaction [Line Items]
Payments made to suppliers		51,000	947,000	$ 2,296,000
Amounts due from related party		$ 0	$ 0

Selected Quarterly Financial _3

Selected Quarterly Financial Data (Components Of Selected Quarterly Financial Data) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Selected Quarterly Financial Information [Abstract]
Net sales	$ 306,627	$ 329,138	$ 363,769	$ 315,047	$ 330,051	$ 356,346	$ 413,613	$ 359,864	$ 1,314,581	$ 1,459,874	$ 1,408,889
Gross profit	124,203	152,858	180,237	148,911	166,747	195,184	234,975	203,362	606,209	800,268	796,911
Net income (loss) attributable to IPG Photonics Corporation	$ (4,450)	$ 57,253	$ 72,272	$ 55,159	$ 75,559	$ 100,517	$ 121,617	$ 106,334	$ 180,234	$ 404,027	$ 347,614
Net income (loss) per share, basic (in dollars per share)	$ (0.08)	$ 1.08	$ 1.36	$ 1.04	$ 1.42	$ 1.88	$ 2.27	$ 1.98	$ 3.40	$ 7.55	$ 6.50
Net income (loss) per share, diluted (in dollars per share)	$ (0.08)	$ 1.07	$ 1.34	$ 1.02	$ 1.40	$ 1.84	$ 2.21	$ 1.93	$ 3.35	$ 7.38	$ 6.36

Uncategorized Items - ipgp-2019

Label	Element	Value
AOCI Attributable to Parent [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption	us-gaap_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoption	$ 10,000