IPG Photonics (IPGP) 10-K 26 Feb 16 2015 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Feb. 24, 2016	Jun. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2,015
Entity Registrant Name	IPG PHOTONICS CORP
Entity Central Index Key	1,111,928
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		52,887,734
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Well-known Seasoned Issuer	Yes
Entity Public Float			$ 3

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
CURRENT ASSETS:
Cash and cash equivalents	$ 582,532	$ 522,150
Short-term investments	106,584	0
Accounts receivable, net	150,479	143,109
Inventories	203,738	171,009
Prepaid income taxes	33,692	20,967
Prepaid expenses and other current assets	25,564	21,295
Deferred income taxes, net	20,346	15,308
Total current assets	1,122,935	893,838
DEFERRED INCOME TAXES, NET	9,386	5,438
GOODWILL	505	455
INTANGIBLE ASSETS, NET	11,904	9,227
PROPERTY, PLANT AND EQUIPMENT, NET	288,604	275,082
OTHER ASSETS	20,095	26,847
TOTAL	1,453,429	1,210,887
CURRENT LIABILITIES:
Revolving line-of-credit facilities	0	2,631
Current portion of long-term debt	2,000	13,333
Accounts payable	26,314	17,141
Accrued expenses and other liabilities	75,667	64,057
Deferred income taxes, net	3,190	3,241
Income taxes payable	37,809	21,672
Total current liabilities	144,980	122,075
DEFERRED INCOME TAXES AND OTHER LONG-TERM LIABILITIES	30,117	22,584
LONG-TERM DEBT, NET OF CURRENT PORTION	17,667	19,667
Total liabilities	$ 192,764	$ 164,326
COMMITMENTS AND CONTINGENCIES (NOTE 10)
IPG PHOTONICS CORPORATION EQUITY:
Common stock, $0.0001 par value, 175,000,000 shares authorized; 52,883,902 shares issued and outstanding at December 31, 2015; 52,369,688 shares issued and outstanding at December 31, 2014	$ 5	$ 5
Additional paid-in capital	607,649	567,617
Retained earnings	833,356	591,202
Accumulated other comprehensive loss	(181,482)	(112,263)
Total IPG Photonics Corporation stockholders' equity	1,259,528	1,046,561
NONCONTROLLING INTERESTS	1,137	0
Total equity	1,260,665	1,046,561
TOTAL	$ 1,453,429	$ 1,210,887

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Common stock, par value	$ 0.0001	$ 0.0001
Common stock, shares authorized	175,000,000	175,000,000
Common stock, shares issued	52,883,902	52,369,688
Common stock, shares outstanding	52,883,902	52,369,688

Consolidated Statements Of Inco

Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
NET SALES	$ 901,265	$ 769,832	$ 648,034
COST OF SALES	409,388	353,314	308,136
GROSS PROFIT	491,877	416,518	339,898
OPERATING EXPENSES:
Sales and marketing	31,868	30,637	26,692
Research and development	63,334	53,403	41,660
General and administrative	57,192	55,338	50,863
(Gain) loss on foreign exchange	(2,560)	(6,618)	2,536
Total operating expenses	149,834	132,760	121,751
OPERATING INCOME	342,043	283,758	218,147
OTHER (EXPENSE) INCOME, Net:
Interest expense, net	(301)	(77)	(1)
Other (expense) income, net	(125)	793	155
Total other (expense) income	(426)	716	154
INCOME BEFORE PROVISION FOR INCOME TAXES	341,617	284,474	218,301
PROVISION FOR INCOME TAXES	(99,590)	(84,029)	(62,521)
NET INCOME	242,027	200,445	155,780
LESS: NET LOSS ATTRIBUTABLE TO NONCONTROLLING INTERESTS	(127)	0	0
NET INCOME ATTRIBUTABLE TO IPG PHOTONICS CORPORATION	$ 242,154	$ 200,445	$ 155,780
NET INCOME ATTRIBUTABLE TO IPG PHOTONICS CORPORATION PER SHARE:
Basic (in dollars per share)	$ 4.60	$ 3.85	$ 3.02
Diluted (in dollars per share)	$ 4.53	$ 3.79	$ 2.97
WEIGHTED AVERAGE SHARES OUTSTANDING:
Basic (in shares)	52,676	52,104	51,548
Diluted (in shares)	53,427	52,824	52,375

Consolidated Statements Of Comp

Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 242,027	$ 200,445	$ 155,780
Other comprehensive (loss) income, net of tax:
Translation adjustments	(69,314)	(110,734)	1,125
Unrealized gain on derivatives	95	172	268
Total other comprehensive (loss) income	(69,219)	(110,562)	1,393
Comprehensive income	172,808	89,883	157,173
Comprehensive (loss) income attributable to noncontrolling interest	(442)	0	0
Comprehensive income attributable to IPG Photonics Corporation	$ 173,250	$ 89,883	$ 157,173

Consolidated Statements Of Equi

Consolidated Statements Of Equity - USD ($) $ in Thousands	Total	COMMON STOCK	ADDITIONAL PAID-IN CAPITAL	RETAINED EARNINGS	ACCUMULATED OTHER COMPREHENSIVE LOSS	TOTAL IPG PHOTONICS CORPORATION STOCKHOLDERS' EQUITY	NONCONTROLLING INTERESTS
Balance, beginning of year (in shares) at Dec. 31, 2012		51,359,247
Balance, beginning of year at Dec. 31, 2012		$ 5	$ 511,039	$ 234,977	$ (3,094)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		540,232
Common stock issued under employee stock purchase plan (in shares)		31,499
Stock-based compensation			11,720
Exercise of stock options and related tax benefit from exercise			14,523
Common stock issued under employee stock purchase plan			1,626
Net income attributable to IPG Photonics Corporation	$ 155,780			155,780
Translation adjustments	1,125				1,125
Unrealized gain on derivatives, net of tax	268				268
LESS: NET LOSS ATTRIBUTABLE TO NONCONTROLLING INTERESTS	0						$ 0
Other comprehensive loss attributable to NCI	0
Balance, end of year (in shares) at Dec. 31, 2013		51,930,978
Balance, end of year at Dec. 31, 2013	927,969	$ 5	538,908	390,757	(1,701)	$ 927,969
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)		402,647
Common stock issued under employee stock purchase plan (in shares)		36,063
Stock-based compensation			15,172
Exercise of stock options and related tax benefit from exercise			11,428
Common stock issued under employee stock purchase plan			2,109
Net income attributable to IPG Photonics Corporation	200,445			200,445
Translation adjustments	(110,734)				(110,734)
Unrealized gain on derivatives, net of tax	172				172
LESS: NET LOSS ATTRIBUTABLE TO NONCONTROLLING INTERESTS	0
Other comprehensive loss attributable to NCI	0
Balance, end of year (in shares) at Dec. 31, 2014		52,369,688
Balance, end of year at Dec. 31, 2014	$ 1,046,561	$ 5	567,617	591,202	(112,263)	1,046,561	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Exercise of stock options (in shares)	447,705	477,785
Common stock issued under employee stock purchase plan (in shares)		36,429
Stock-based compensation			18,989
Exercise of stock options and related tax benefit from exercise			18,582
Common stock issued under employee stock purchase plan			2,461
Net income attributable to IPG Photonics Corporation	$ 242,154			242,154
Translation adjustments	(69,314)				(69,314)
Unrealized gain on derivatives, net of tax	95				95
NCI of acquired company							1,579
LESS: NET LOSS ATTRIBUTABLE TO NONCONTROLLING INTERESTS	(127)
Other comprehensive loss attributable to NCI	442						(315)
Balance, end of year (in shares) at Dec. 31, 2015		52,883,902
Balance, end of year at Dec. 31, 2015	$ 1,260,665	$ 5	$ 607,649	$ 833,356	$ (181,482)	$ 1,259,528	$ 1,137

Consolidated Statements Of Cash

Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 242,027	$ 200,445	$ 155,780
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	42,415	35,612	31,524
Deferred income taxes	(7,153)	(1,486)	(6,168)
Stock-based compensation	18,989	15,172	11,720
Unrealized gains on foreign currency transactions	(5,491)	(3,497)	(235)
Other	510	459	62
Provisions for inventory, warranty and bad debt	39,985	28,036	29,975
Changes in assets and liabilities that (used) provided cash:
Accounts receivable	(19,036)	(48,518)	(9,991)
Inventories	(70,565)	(42,246)	(50,355)
Prepaid expenses and other current assets	1,853	(5,351)	(3,980)
Accounts payable	9,806	3,262	974
Accrued expenses and other liabilities	613	(1,567)	(281)
Income and other taxes payable	9,529	5,763	(30,784)
Tax benefit from exercise of employee stock options	(6,911)	(5,979)	(8,874)
Net cash provided by operating activities	256,571	180,105	119,367
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(70,119)	(88,601)	(70,919)
Purchase of intangible assets	0	(2,000)	0
Proceeds from sales of property, plant and equipment	164	434	236
Proceeds from sale of investment	0	0	495
Purchases of short-term investments	(106,747)	0	0
Acquisition of businesses	(4,958)	0	(5,555)
Other	93	87	(143)
Net cash used in investing activities	(181,567)	(90,080)	(75,886)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from line-of-credit facilities	12,887	33,282	16,843
Payments on line-of-credit facilities	(15,227)	(33,623)	(15,990)
Principal payments on long-term borrowings	(13,333)	(1,667)	(2,853)
Exercise of employee stock options and issuances under employee stock purchase plan	14,132	7,558	7,275
Tax benefit from exercise of employee stock options	6,911	5,979	8,874
Net cash provided by financing activities	5,370	11,529	14,149
EFFECT OF CHANGES IN EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	(19,992)	(28,180)	7,093
NET INCREASE IN CASH AND CASH EQUIVALENTS	60,382	73,374	64,723
CASH AND CASH EQUIVALENTS — Beginning of period	522,150	448,776	384,053
CASH AND CASH EQUIVALENTS — End of period	582,532	522,150	448,776
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	873	253	208
Cash paid for income taxes	91,329	73,544	89,611
Non-cash transactions:
Demonstration units transferred from inventory to other assets	3,181	3,528	3,927
Property, plant and equipment transferred from inventory	2,951	1,551	0
Additions to property, plant and equipment included in accounts payable	350	1,084	2,132
Property purchase financed with debt	$ 0	$ 22,000	$ 0

Nature Of Business And Summary

Nature Of Business And Summary Of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
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") is the leading developer and manufacturer of a broad line of high-performance fiber lasers, fiber amplifiers and diode lasers that are used for diverse applications, primarily in materials processing. Its world headquarters are located in Oxford, Massachusetts. It also has facilities and sales offices elsewhere in the United States, Europe and Asia. Principles of Consolidation — The Company was incorporated as a Delaware corporation in December 1998. 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 Investments — Cash and cash equivalents consist primarily of highly liquid investments, such as bank deposits, marketable securities with original maturities of three months or less with insignificant interest rate risk and marketable securities with remaining maturities of three months or less at the date of acquisition. Short-term investments consist primarily of similar highly liquid investments and marketable securities with insignificant interest rate risk and with original maturities greater than three months but less than one year. 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. Because of the Company's vertical integration, a significant or sudden decrease in sales activity could result in a significant change in the estimates of excess or obsolete inventory valuation. The costs associated with provisions for excess quantities, technological obsolescence, or component rejections are charged to cost of sales as incurred. 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 30 years Machinery and equipment 5-12 years Office furniture and fixtures 3-5 years Expenditures for maintenance and repairs are charged to operations. Interest expense associated with significant capital projects is capitalized as a cost of the project. The Company capitalized $0 , $383 and $524 of interest expense in 2015 , 2014 and 2013 , respectively. Long-Lived Assets — Long-lived assets, which consist primarily of property, plant and equipment, are reviewed by management for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. In cases in which 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. No impairment losses have been recorded during the periods presented. 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 $3,229 and $3,612 at December 31, 2015 and 2014 , respectively. Amortization expense of demonstration equipment for the years ended December 31, 2015 , 2014 and 2013 , was $2,345 , $2,068 and $2,725 , respectively. 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. 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. 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 five to ten years or over the period the economic benefits of the intangible asset are consumed. Revenue Recognition — The Company recognizes revenue in accordance with ASC 605. Revenue from orders with multiple deliverables is divided into separate units of accounting when certain criteria are met. These separate units generally consist of equipment and installation. The consideration for the arrangement is allocated to the separate units of accounting based on their relative selling prices. The selling price of equipment is based on vendor-specific objective evidence which is the sales price of equipment sold without installation. The selling price of installation is based on third-party evidence which is the fair value of installation services offered by third parties. Revenue for laser and amplifier sources generally is recognized upon the transfer of ownership which is typically at the time of shipment. Installation revenue is recognized upon completion of the installation service which typically occurs within 30 to 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. Returns and customer credits are infrequent and are recorded as a reduction to revenue. Rights of return generally are not included in sales arrangements. Accounts Receivable and Allowance for Doubtful Accounts — Accounts Receivable include $24,307 and $25,150 of bank acceptance drafts at December 31, 2015 and 2014 , respectively. Bank acceptance drafts are bank guarantees of payment on specified dates. The maturity of these bank acceptance drafts is less than 90 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: 2015 2014 2013 Balance at January 1 $ 1,890 $ 2,473 $ 2,173 Provision for bad debts, net of recoveries 427 579 323 Uncollectable accounts written off (114 ) (617 ) (31 ) Foreign currency translation (392 ) (545 ) 8 Balance at December 31 $ 1,811 $ 1,890 $ 2,473 Warranties — The Company typically provides one to three -year parts and service warranties on lasers and amplifiers. Most of the Company's sales offices provide support to customers in their respective geographic areas. The Company estimates the warranty accrual considering past claims experience, the number of units still covered by warranty and the average life of the remaining warranty period. The warranty accrual has generally been sufficient to cover product warranty repair and replacement costs. Activity related to the warranty accrual was as follows: 2015 2014 2013 Balance at January 1 $ 19,272 $ 14,997 $ 10,714 Provision for warranty accrual 22,808 15,449 11,363 Warranty claims (12,208 ) (9,165 ) (7,405 ) Foreign currency translation and other (1,662 ) (2,009 ) 325 Balance at December 31 $ 28,210 $ 19,272 $ 14,997 Accrued warranty reported in the accompanying consolidated financial statements as of December 31, 2015 and December 31, 2014 consists of $14,871 and $9,489 in accrued expenses and other liabilities and $13,339 and $9,783 in other long-term liabilities, respectively. Stock-Based Compensation — The Company accounts for stock-based compensation in accordance with ASC 718. Under the fair value recognition provision of ASC 718, the Company accounts for stock-based compensation 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 uses historical data to estimate pre-vesting option and restricted stock unit forfeitures and record stock-based compensation expense in its statements of income only for those options and awards that are expected to vest. The Company estimates forfeitures at the time of grant and revise these estimates, if necessary, in subsequent periods if actual forfeitures differ from the estimates. 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. The description of the Company's stock-based employee compensation plans and the assumptions it uses to calculate the fair value of stock-based employee compensation is more fully described in Note 2. 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 our website. The Company's advertising costs were not material for the periods presented. Research and Development — Research and development costs are expensed as incurred. 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 carryforwards and credits 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 by it 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-term investments, auction rate securities and accounts receivable. The Company maintains substantially all of its cash, short-term investments and marketable securities in six 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 provide a reserve for potential credit losses. Such losses historically have been within management's expectations (see discussion related to significant customers in Note 15). Fair Value of Financial Instruments — 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 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 cash equivalents, short-term investments, 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 these instruments or as a result of the competitive market interest rates, which have been negotiated. The following table presents information about the Company's assets and liabilities measured at fair value: Fair Value Measurements at December 31, 2015 Total Level 1 Level 2 Level 3 Assets Cash equivalents $ 214,232 $ 214,232 $ — $ — Short-term investments 106,375 106,375 — — Auction rate securities 1,136 — — 1,136 Total assets $ 321,743 $ 320,607 $ — $ 1,136 Liabilities Collateralized long-term note $ 19,667 $ 19,667 $ — $ — Contingent purchase consideration $ 20 $ — $ — $ 20 Total liabilities $ 19,687 $ 19,667 $ — $ 20 Fair Value Measurements at December 31, 2014 Total Level 1 Level 2 Level 3 Assets Cash equivalents $ 266,011 $ 266,011 $ — $ — Auction rate securities 1,128 — — 1,128 Total assets $ 267,139 $ 266,011 $ — $ 1,128 Liabilities Collateralized long-term note $ 21,667 $ 21,667 $ — $ — Contingent purchase consideration $ 98 $ — $ — $ 98 Interest rate swap 151 — 151 — Total liabilities $ 21,916 $ 21,667 $ 151 $ 98 Short-term investments are measured and recorded at book value as unrealized gains or losses are not adjusted since they are considered held-to-maturity and consist of liquid investments including U.S. government and government agency notes, corporate notes, commercial paper and certificates of deposit with original maturities of greater than three months but less than one year. The fair value of these investments at December 31, 2015 was $106,375 which represents an unrealized loss of $209 as compared to the $106,584 recorded on the Consolidated Balance Sheets as of December 31, 2015. 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 secondary markets for the securities held by the Company. The auction rate securities are considered available-for-sale securities. They had a cost basis of $1,450 at December 31, 2015 and December 31, 2014 . The Company previously had a cash flow hedge which was an interest rate swap associated with the U.S. long-term note. The interest rate swap agreement terminated with the note, which matured in June 2015. The fair value amount in the consolidated balance sheet related to the interest rate swap was estimated based on quoted market prices or pricing models using current market rates. The fair value at December 31, 2014 for the interest rate swap considered prices observed in inactive secondary markets for the securities held by the Company. The fair value of contingent consideration was determined using an income approach at the respective business combination dates 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 business combinations that give rise to contingent consideration are more fully described in Note 12. The following table presents information about the Company's movement in Level 3 assets and liabilities measured at fair value: 2015 2014 2013 Auction Rate Securities Balance, January 1 $ 1,128 $ 1,120 $ 1,112 Change in fair value and accretion 8 8 8 Balance, December 31 $ 1,136 $ 1,128 $ 1,120 Contingent Purchase Consideration Balance, January 1 $ 98 $ 375 $ 3,023 Period transactions (50 ) — — Change in fair value and currency fluctuations (28 ) (277 ) (2,648 ) Balance, December 31 $ 20 $ 98 $ 375 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 and unrealized gains or losses on derivatives. These adjustments are accumulated within the consolidated statements of comprehensive income. Total components of accumulated other comprehensive loss were as follows: December 31, 2015 2014 Foreign currency translation adjustments $ (181,725 ) $ (112,411 ) Unrealized gain (loss) on derivatives, net of tax of $45 and $67 11 (84 ) Change in carrying value of auction rate securities 232 232 Accumulated other comprehensive loss $ (181,482 ) $ (112,263 ) 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. The Company has no derivatives outstanding as of December 31, 2015 . Cash Flow Hedges — The Company's previous cash flow hedge was an interest rate swap under which it payed fixed rates of interest. The fair value amounts in the consolidated balance sheets were: Notional Amounts 1 Other Assets Other Current Liabilities Deferred Income Taxes And Other Long-Term Liabilities December 31, December 31, December 31, December 31, 2015 2014 2015 2014 2015 2014 2015 2014 $ — $ 11,333 $ — $ — $ — $ 151 $ — $ — (1) Notional amounts represent the gross contract/notional amount of the derivative outstanding. The derivative gains and losses in the consolidated statements of income for the years ended December 31, 2015 , 2014 and 2013 , related to the Company's previous interest rate swap contract was as follows: Year Ended December 31, 2015 2014 2013 Effective portion recognized in other comprehensive (loss) income, pretax: Interest rate swap $ 304 $ 567 $ 881 Effective portion reclassified from other comprehensive (loss) income to interest expense, pretax: Interest rate swap $ (153 ) $ (295 ) $ (449 ) Ineffective portion recognized in income: Interest rate swap $ — $ — $ — Business Segment Information — The Company operates in one segment which involves the design, development, production and distribution of fiber lasers, 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 decision maker, who is the Company's chief executive officer, measures financial performance as a single enterprise and not on legal entity or end market basis. Throughout the year, the chief decision maker allocates capital resources on a project-by-project basis across the Company's entire asset base to maximize profitability without regard to 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 geographic financial information and product lines is provided in Note 15. Earnings Per Share — The Company computes net income per share in accordance with ASC 260- Earnings Per Share . Recent Accounting Pronouncements — In November, the FASB issued amended guidance that clarifies that in a classified statement of financial position, an entity shall classify deferred tax liabilities and assets as non-current amounts. The new guidance supersedes ASC 740-10-45-5 which required the valuation allowance for a particular tax jurisdiction be allocated between current and non-current deferred tax assets for that tax jurisdiction on a pro rata basis. The new standard will become effective for the Company's fiscal year beginning January 1, 2017. The Company is currently assessing the impact of this amended guidance and the timing of adoption. In May 2014, FASB issued Accounting Standards Update No. 2014-09 ("ASU 2014-09") "Revenue from Contracts with Customers." ASU 2014-09 supersedes the revenue recognition requirements in "Revenue Recognition (Topic 605)", and requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. As currently issued and amended, ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, though early adoption is permitted for annual reporting periods beginning after December 15, 2016. The Company is currently in the process of evaluating the impact of the adoption of ASU 2014-09 on its consolidated financial statements and does not expect it to have a material impact on its financial statements upon adoption. Subsequent Events — The Company has considered the impact of subsequent events through the filing date of these financial statements.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION Stock-based compensation is included in the following financial statement captions: Year Ended December 31, 2015 2014 2013 Cost of sales $ 5,316 $ 4,153 $ 3,187 Sales and marketing 1,998 1,567 1,195 Research and development 4,049 3,033 1,929 General and administrative 7,626 6,419 5,409 Total stock-based compensation 18,989 15,172 11,720 Tax benefit recognized (6,141 ) (4,865 ) (3,784 ) Net stock-based compensation $ 12,848 $ 10,307 $ 7,936 Incentive Plans — In April 2000, the Company's board of directors adopted the 2000 Incentive Compensation Plan (the "2000 Plan"), and in February 2006, the Company's board of directors adopted the 2006 Incentive Compensation Plan (the "2006 Plan"), which provide for the issuance of stock options and other stock and non-stock based awards to the Company's directors, employees, consultants and advisors. The Company reserved 5,833,333 shares under the 2000 Plan and 4,000,000 shares under the 2006 Plan for the issuance of awards under the plans. During 2011, the Company reserved an additional 6,084,273 shares under the 2006 Plan including 84,273 shares authorized but not issued. In June 2006, the Company's board of directors adopted the Non-Employee Directors Stock Plan (the "Directors Plan") for non-employee directors. The Company reserved 486,660 shares for issuance under the Directors Plan. In June 2015, the stockholders approved an amendment of the 2006 Plan under which 194,919 shares authorized under the Directors Plan were rolled into the 2006 Plan. Under the three plans, the Company may grant nonstatutory stock options at an exercise price at least equal to the fair value of its common stock on the date of grant, unless the board of directors or compensation committee determines otherwise on the date of grant. Incentive stock options may be granted under the 2000 Plan and the 2006 Plan at exercise prices equal to or exceeding the fair value of the common stock on the date of grant. The Company may also grant restricted stock, restricted stock units, performance stock units, other equity-based awards and cash. Incentive awards generally become exercisable over periods of one to five years and expire seven to ten years from the date of the grant. The awards under the 2000 Plan and the 2006 Plan may become exercisable earlier upon the occurrence of certain change of control events at the election of the board of directors or compensation committee, and all awards under the Directors Plan automatically become exercisable upon a change of control. All shares issued under the incentive plans are registered shares newly issued by the Company. At December 31, 2015 , 5,078,138 shares of the Company's stock were available for future grant under the 2006 Plan. No further grants can be made under the 2000 Plan or the Directors Plan. Compensation cost for all stock-based payment awards is based on the estimated grant-date fair value. The Company allocates and records stock-based compensation expense on a straight-line basis over the requisite service period. Determining the appropriate fair value model and calculating the fair value of stock-based payment awards requires the use of highly subjective assumptions, including the expected life of the stock-based payment awards and stock price volatility. The assumptions used in calculating the fair value of stock-based payment awards represent management’s best estimates, but the estimates involve inherent uncertainties and the application of management judgment. As a result, if factors change and the Company uses different assumptions, its stock-based compensation expense could be materially different in the future. The Company calculates the fair value of stock option grants using the Black-Scholes option pricing model. The assumptions used in the Black-Scholes model or the calculation of compensation were as follows for the years ended December 31. 2015 2014 2013 Expected term 4.4-6.3 years 4.7-6.1 years 4.4-6.3 years Volatility 45%-48% 48%-51% 51%-54% Risk-free rate of return 1.38%-1.74% 1.46%-1.84% 0.74%-1.32% Dividend yield 0.25% 0.25% 0.25% Forfeiture rate 3.47%-5.88% 3.04%-5.86% 0%-5.97% A summary of option activity is presented below (see Note 11 for further information): Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2015 2,488,350 $ 45.48 Granted 223,694 96.56 Exercised (447,705 ) 28.28 Forfeited (40,170 ) 60.38 Outstanding — December 31, 2015 2,224,169 $ 53.82 6.20 $ 80,292 Vested or expected to vest — December 31, 2015 2,137,468 $ 52.91 6.12 $ 78,937 Exercisable — December 31, 2015 1,050,513 $ 36.24 4.70 $ 55,592 The intrinsic value of the options exercised during the years ended December 31, 2015 , 2014 and 2013 , was $27,207 , $20,474 and $29,473 , respectively. The weighted-average grant fair value per share for options granted during the years ended December 31, 2015 , 2014 and 2013 , was $42.78 , $32.53 and $28.28 , respectively. The total compensation cost related to non-vested awards not yet recorded at December 31, 2015 was $17,009 which is expected to be recognized over a weighted-average of 2.2 years. The aggregate fair value of awards vested during the year ended December 31, 2015 was $12,034 . The following table summarizes the restricted stock units ("RSU's") activity for the year ended December 31, 2015 : Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2015 203,526 $ 62.44 Granted 120,365 95.25 Converted (41,487 ) 57.67 Canceled (4,685 ) 71.05 Outstanding — December 31, 2015 277,719 $ 77.22 8.25 24,761,000 $ 24,761 Vested or expected to vest — December 31, 2015 251,143 $ 76.65 8.22 22,392,000 $ 22,392 The intrinsic value of the RSU's exercised during the years ended December 31, 2015 , 2014 and 2013 , was $3,705 , $3,017 and $590 , respectively. The weighted-average grant fair value per share for RSU's granted during the years ended December 31, 2015 , 2014 and 2013 , was $95.25 , $69.22 and $59.40 , respectively. The total compensation cost related to non-vested awards not yet recorded at December 31, 2015 was $11,856 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, 2015 was $2,393 . The Company grants performance stock units to 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 and could range from no units to a maximum of twice the amount of awarded units. The weighted-average fair value of these performance units was determined using the Monte Carlo simulation model incorporating the following weighted-average assumptions: 2015 Expected term 3.2 years Volatility 12%-36% Risk-free rate of return 0.98% Dividend yield —% Weighted-average fair value per share 128.42 The following table summarizes the performance stock units ("PSU's") activity for the year ended December 31, 2015 : Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2015 — $ — Granted 27,233 128.54 Converted Canceled Outstanding — December 31, 2015 27,233 $ 128.54 9.15 $ 2,428 Vested or expected to vest — December 31, 2015 24,366 $ 128.54 9.15 $ 2,172 PSU's are included at 100% of target goal; under the terms of the awards, the recipient may earn between 0% and 200% of the awarded units. The total compensation cost related to nonvested awards not yet recorded at December 31, 2015 was $2,467 which is expected to be recognized over a weighted average of 3.2 years.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventories	INVENTORIES Inventories consist of the following: December 31, 2015 2014 Components and raw materials $ 70,394 $ 54,925 Work-in-process 43,259 58,603 Finished goods 90,085 57,481 Total $ 203,738 $ 171,009 The Company recorded inventory provisions totaling $15,364 , $11,302 and $15,128 for the years ended December 31, 2015 , 2014 and 2013 , 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.

Property, Plant And Equipment

Property, Plant And Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	PROPERTY, PLANT AND EQUIPMENT Property, plant, and equipment consist of the following: December 31, 2015 2014 Land $ 18,962 $ 19,248 Buildings 166,784 144,629 Machinery and equipment 226,724 202,075 Office furniture and fixtures 26,981 25,816 Construction-in-progress 35,946 47,285 Total property, plant and equipment 475,397 439,053 Accumulated depreciation (186,793 ) (163,971 ) Total property, plant and equipment — net $ 288,604 $ 275,082 The Company recorded depreciation expense of $37,796 , $31,334 and $26,489 for the years ended December 31, 2015 , 2014 and 2013 , respectively.

Accrued Expenses And Other Liab

Accrued Expenses And Other Liabilities	12 Months Ended
	Dec. 31, 2015
Payables and Accruals [Abstract]
Accrued Expenses And Other Liabilities	ACCRUED EXPENSES AND OTHER LIABILITIES Accrued expenses and other liabilities consist of the following: December 31, 2015 2014 Accrued compensation $ 33,617 $ 31,673 Customer deposits and deferred revenue 21,525 16,605 Current portion of accrued warranty 14,871 9,489 Other 5,654 6,290 Total $ 75,667 $ 64,057

Financing Arrangements

Financing Arrangements	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Financing Arrangements	FINANCING ARRANGEMENTS The Company's borrowings under existing financing arrangements consist of the following: December 31, 2015 2014 Revolving line of credit facilities: European overdraft facilities $ — $ 828 Euro line of credit — 1,803 Total $ — $ 2,631 Term debt: U.S. long-term note $ — $ 11,333 Collateralized long-term note 19,667 21,667 Less: current portion (2,000 ) (13,333 ) Total long-term debt $ 17,667 $ 19,667 The U.S. and Euro lines of credit are available to certain foreign subsidiaries and allow for borrowings in the local currencies of those subsidiaries. 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, 2015 , there were no outstanding drawings, however there were $2,828 of guarantees issued against the line which reduced the total availability. At December 31, 2015 , the remaining availability under this line was $47,172 . 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 it 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 our cash held in the U.S.A. in excess of $50 million up to a maximum of $250 million . 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 30,000 ( $32,719 at December 31, 2015 ), expiring in July 2017. 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, 2015 , there were no drawings, however there were $8,221 of guarantees issued against the line which reduced the total availability. At December 31, 2015 , the remaining availability under this line was $24,498 . Euro Overdraft Facilities — The Company maintains a syndicated overdraft facility with available principal of Euro 500 ( $545 at December 31, 2015 ) with no expiration date. This facility bears interest at market rates that vary depending upon the bank within the syndicate that advances the principal outstanding. At December 31, 2015 , there were no outstanding drawings and the aggregate remaining availability under this line was $545 . Other European Facilities — The Company maintains two Euro credit lines in Italy with aggregate available principal of Euro 1,500 ( $1,636 as of December 31, 2015 ) which bear interest at market rates and expire in June and September 2016. At December 31, 2015 , there were no outstanding drawings and the aggregate remaining availability under these lines was $1,636 . These facilities are collateralized by a common pool of the assets of the Company's Italian subsidiary. Term Debt: U.S. Long-Term Note — The U.S. long-term note outstanding at December 31, 2014 matured and was paid in June 2015. Collateralized Long-Term Note —In October 2014, the Company entered into a collateralized long-term note to finance the purchase of the Company's aircraft which bears a fixed interest rate of 2.81% per annum. The note requires monthly principal payments of $167 and interest through October 2019, at which time the remaining principal is payable. As of December 31, 2015 , the note has a remaining balance of $19,667 .

Noncontrolling Interest and Sto

Noncontrolling Interest and Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Noncontrolling Interest [Abstract]
Noncontrolling Interests and Stockholders' Equity	NONCONTROLLING INTEREST AND EQUITY Noncontrolling Interest — Noncontrolling interest reported in the accompanying consolidated financial statements relates to a 76% ownership interest in RukhTekh LLC ("RuchTech") that was purchased on March 15, 2015. The associated net loss attributable to noncontrolling interest in 2015 was $127 . Information regarding RuchTech's purchase is provided in Note 12. 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, 2015 .

Related-Party Transactions

Related-Party Transactions	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Related-Party Transactions	RELATED-PARTY TRANSACTIONS In 2015 and 2014 , the Company purchased various equipment, parts and services from a company for which one of the Company's independent directors is an executive officer. The payments made for such equipment, parts and services for 2015 and 2014 totaled $683 and $3,687 , respectively. There were no amounts due to this company at December 31, 2015 or at December 31, 2014 and there were outstanding purchase orders for equipment and services of $5,873 at December 31, 2015. The Company leased from an unrelated third party approximately 12,000 square feet of office space in Marlborough, Massachusetts under an office lease expiring July 2020. A subsidiary of IP Fibre Devices (UK) Ltd. ("IPFD") purchased the building in October 2014 and acquired the lease, which was amended in 2015 to increase the office space leased to the Company. The Company's CEO is the managing director of IPFD. The Company's CEO and other members of management own shares of IPFD which is a stockholder of the Company. The 2015 year-end annual lease rate was $794 with an annual increase of approximately 2.5% per year. The Company reimburses the landlord for its portion of certain operational costs. The Company paid IPFD $531 and $20 for 2015 and 2014, respectively, under the office lease. The Company has an option to rent additional space in the building as it becomes available. The CEO leases the right to use 25% of the Company's aircraft annually under a October 2014 lease expiring November 2019. The 2015 year-end annual lease rate was $651 and future rent payments will be adjusted annually. The CEO paid the Company $651 and $146 in 2015 and 2014 , respectively, under the aircraft lease. In addition, the CEO directly pays others for the operating costs of his private use including pilot fees, fuel and other costs. In 2015 and 2014 , the Company sold products and services of $497 and $2,731 to OAO "RCE" Laser Processing Center ("Laser Center"), an application development and parts processing company. The Company's CEO owns approximately 39% of Laser Center, which he acquired from an unrelated third party in 2014 . In 2015 , the Company sold products of $146 to a company for which one of the Company's independent directors is a non-management member of the board of directors.

Net Income Attributable To IPG

Net Income Attributable To IPG Photonics Corporation Per Share	12 Months Ended
	Dec. 31, 2015
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, 2015 2014 2013 Net income attributable to IPG Photonics Corporation $ 242,154 $ 200,445 $ 155,780 Net income attributable to common stockholders 242,154 200,445 155,780 Weighted average shares 52,676 52,104 51,548 Dilutive effect of common stock equivalents 751 720 827 Diluted weighted average common shares 53,427 52,824 52,375 Basic net income attributable to IPG Photonics Corporation per share $ 4.60 $ 3.85 $ 3.02 Basic net income attributable to common stockholders $ 4.60 $ 3.85 $ 3.02 Diluted net income attributable to IPG Photonics Corporation per share $ 4.53 $ 3.79 $ 2.97 Diluted net income attributable to common stockholders $ 4.53 $ 3.79 $ 2.97 For the years ended December 31, 2015 , 2014 and 2013 , respectively, the computation of diluted weighted average common shares excludes common stock equivalents of 29,127 shares, 46,987 shares and 322,301 shares which includes RSU's of 18,171 , 13,300 and 6,635 and PSU's of 3,369 , 0 and 0 , because the effect would be anti-dilutive.

Commitments And Contingencies

Commitments And Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments And Contingencies	COMMITMENTS AND CONTINGENCIES Operating Leases — The Company leases certain facilities under cancelable and noncancelable operating lease agreements which expire through October 2019. In addition, it leases capital equipment under operating leases. Rent expense for the years ended December 31, 2015 , 2014 and 2013 , totaled $7,365 , $5,516 and $4,560 , respectively. Commitments under the noncancelable lease agreements as of December 31, 2015 are as follows: Years Ending December 31 Facilities Equipment Total 2016 $ 2,843 $ 850 $ 3,693 2017 1,983 538 2,521 2018 1,477 327 1,804 2019 1,191 53 1,244 2020 322 15 337 Thereafter — — — Total $ 7,816 $ 1,783 $ 9,599 Employment Agreements — The Company has entered into employment agreements with certain members of senior management. The terms of these agreements are up to three years and include noncompetition, nonsolicitation and nondisclosure provisions, as well as provisions for defined severance for terminations of employment under certain conditions and a change of control of the Company. The Company also maintains a severance plan for certain of its senior management providing for defined severance for terminations of employment under certain conditions and a change of control of the Company. 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 $17,961 and $22,288 as of December 31, 2015 and 2014 , respectively. Included in 2014, was an obligation of $4,500 that the Company had as a result of entering into an agreement to purchase a 76% ownership interest in RuchTech. 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. In November 2015, the Company was sued in the United States District Court, Eastern District of Texas, for patent infringement relating to an apparatus for coupling radiation beams into optical waveguides. The complaint seeks unspecified monetary damages, treble damages, injunctive relief and attorneys fees. The Company believes it has meritorious defenses and intends to vigorously contest the claims. As such, no amounts have been accrued in respect of this contingency. As of December 31, 2015 and through the date of the Company's subsequent review period of February 26, 2016 , the Company has no other legal proceedings ongoing that management estimates could have a material effect on the Company's Consolidated Financial Statements.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
Compensation Related Costs [Abstract]
Employee Benefit Plans	EMPLOYEE BENEFIT PLANS The Company maintains a 401(k) retirement savings plan offered to all of its U.S. employees. The Company makes matching contributions equal to 50% of the employee's contributions, subject to a maximum of 6% of eligible compensation. Compensation expense related to its contribution to the plan for the years ended December 31, 2015 , 2014 and 2013 , approximated $2,021 , $1,445 and $1,127 , respectively. 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 -month purchase period. Payroll deductions may not exceed 10% of the employee's compensation and are subject to other limitations. Compensation expense related to the employee stock purchase plan was $680 , $607 and $498 for the years ended December 31, 2015 , 2014 and 2013 , respectively. As of December 31, 2015 , there were 356,344 shares available for issuance under the employee stock purchase plan.

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Business Combinations	BUSINESS COMBINATIONS On March 15, 2015, the Company purchased a 76% ownership interest in RuchTech. RuchTech's fair value at the date of acquisition was $6,579 . The Company paid $5,000 , which represents the fair value of its ownership interest on that date. In connection with this purchase, the Company recorded intangibles assets of $6,298 which related to purchased technology with an estimated useful life of 7 years and $64 of Goodwill that are not deductible for federal income tax purposes. The purchase did not have a material effect on the Company's financial results in 2015. On March 13, 2013, the Company acquired the working capital and long term assets of Mobius Photonics Inc. ("Mobius"), a manufacturer of high-power pulsed ultra-violet ("UV") fiber lasers for micro-machining and fine processing applications. As a result of the acquisition, the Company recorded intangible assets of $4,480 which related to production know-how with an estimated useful life of 7 years and $505 of goodwill that is deductible for federal income tax purposes. The acquisition did not have a material effect on the Company's financial results in 2013.

Goodwill And Intangibles

Goodwill And Intangibles	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill And Intangibles	GOODWILL AND INTANGIBLES The following table sets forth the changes in the carrying amount of goodwill for the years ended December 31, 2015 and 2014 : December 31, 2015 December 31, 2014 Balance at January 1 $ 455 $ 455 Foreign exchange adjustment (14 ) — Total goodwill arising from purchase 64 — Balance at December 31 $ 505 $ 455 The goodwill balance at January 1, 2015 of $455 relates to the expected synergies for the Company's expansion of product offerings with UV fiber lasers from the acquisition of Mobius in 2013. The goodwill arising from the acquisition is deductible over 15 years for federal tax purposes. The goodwill arising from purchase during 2015 of $64 , largely reflected the expected synergies for the Company's high-power systems product line resulting from the 2015 purchase of a 76% ownership interest in RuchTech. The goodwill arising from the purchase is no t deductible for federal tax purposes. Intangible assets, subject to amortization, consisted of the following: December 31, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Patents $ 6,641 $ (4,573 ) $ 2,068 6 Years $ 6,641 $ (4,221 ) $ 2,420 6 Years Customer relationships 3,325 (3,092 ) 233 5 Years 3,660 (3,308 ) 352 5 Years Production know-how 6,672 (3,339 ) 3,333 8 Years 6,844 (2,630 ) 4,214 8 Years Technology, trademark and tradename 8,247 (1,977 ) 6,270 8 Years 3,315 (1,074 ) 2,241 8 Years $ 24,885 $ (12,981 ) $ 11,904 $ 20,460 $ (11,233 ) $ 9,227 During the third quarter of 2014, the Company purchased certain intellectual property including patent and product design rights in the amount of $2,000 . In connection with the Company's purchase of a 76% ownership interest in Ruchtech during the first quarter of 2015, it recorded $6,298 of purchased technology intangibles which are included in the table above. Amortization expense for the years ended December 31, 2015 , 2014 and 2013 was $2,274 , $2,210 and $2,310 , respectively. The estimated future amortization expense for intangibles as of December 31, 2015 is as follows: 2016 2017 2018 2019 2020 Thereafter Total $2,377 $2,239 $2,175 $2,122 $1,374 $1,617 $11,904 Impairment — In accordance with ASC 350- Intangibles-Goodwill and Other , the Company assesses the impairment of its long-lived assets including its definite-lived intangible assets and goodwill, at least annually for goodwill, and whenever changes in events or circumstances indicate that the carrying value of such assets may not be recoverable. During each reporting period, the Company assesses for factors that may be present which would cause an impairment review.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
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: 2015 2014 2013 U.S. $ 94,242 $ 72,800 $ 59,006 Foreign 247,375 211,674 159,295 Total $ 341,617 $ 284,474 $ 218,301 The Company's provision for income taxes for the years ended December 31 consisted of the following: 2015 2014 2013 Current: Federal $ (30,334 ) $ (22,549 ) $ (19,285 ) State (6,616 ) (2,823 ) (2,617 ) Foreign (69,793 ) (60,143 ) (46,787 ) Total current $ (106,743 ) $ (85,515 ) $ (68,689 ) Deferred: Federal $ 6,303 $ 454 $ 3,834 State 312 27 203 Foreign 538 1,005 2,131 Total deferred $ 7,153 $ 1,486 $ 6,168 Provision for income taxes $ (99,590 ) $ (84,029 ) $ (62,521 ) 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, is as follows: 2015 2014 2013 Tax at statutory rate $ (119,566 ) $ (99,867 ) $ (76,406 ) Non-U.S. rate differential — net 15,931 14,590 10,761 State income taxes — net (2,094 ) (1,787 ) (1,512 ) Effect of changes in enacted tax rates on deferred tax assets and liabilities (153 ) (44 ) 186 Nondeductible stock compensation expense (338 ) (483 ) (101 ) Other nondeductible expenses (1,039 ) (2,063 ) (1,666 ) Federal and state tax credits 8,837 5,865 7,500 Change in reserves, including interest and penalties (1,522 ) (7 ) (1,273 ) Change in valuation allowance (620 ) — — Other — net 974 (233 ) (10 ) $ (99,590 ) $ (84,029 ) $ (62,521 ) The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, are as follows: 2015 2014 2013 Property, plant and equipment $ (8,031 ) $ (5,310 ) $ (2,230 ) Inventory provisions 14,566 10,497 8,261 Allowances and accrued liabilities 2,590 1,570 3,634 Other tax credits 3,763 726 769 Deferred compensation 5,891 4,218 (434 ) Net operating loss carryforwards 923 — 229 Valuation allowance (678 ) — — Net deferred tax assets $ 19,024 $ 11,701 $ 10,229 It is the Company's practice and intention to reinvest the earnings of non-U.S. subsidiaries in those operations. Accordingly, it has not made any provision for additional U.S. or foreign withholding taxes with respect to repatriation of earnings of non-U.S. subsidiaries. At December 31, 2015 and 2014 , the cumulative unremitted earnings that are reinvested in non-U.S. subsidiaries are approximately $734,000 and $522,000 , respectively. As of December 31, 2015 , 2014 and 2013 , the Company has state tax credit carry-forwards of $3,740 , $1,225 and $2,074 , respectively. The state tax credit carry-forwards begin expiring in 2018. In addition, 2014 includes for the Company net operating loss carry-forwards available for future periods of $2,509 related to deductions for stock-based compensation for its UK subsidiary. The UK net operating loss can be carry-forward indefinitely. These amounts are not included in deferred tax assets, because when these net operating loss and state tax credit carry-forwards are utilized they will be credited to additional paid-in capital. The following is a tabular reconciliation of the total amounts of unrecognized tax benefits: 2015 2014 2013 Balance at January 1 $ 6,494 $ 6,501 $ 5,392 Change in prior period positions 33 (795 ) (505 ) Additions for tax positions in current period 1,052 788 1,614 Balance at December 31 $ 7,579 $ 6,494 $ 6,501 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 are $437 , $(192) and $374 for the years ended December 31, 2015 , 2014 and 2013 , respectively, and are included within the provision for income taxes. Total accrued penalties and interest related to the underpayment of income taxes are $1,107 and $670 at December 31, 2015 and 2014 , respectively. The Company's uncertain tax positions are related to tax years that remain subject to examination by the relevant taxing authorities. If realized, all of the Company's uncertain tax positions would affect its effective tax rate. Certain of the Company's uncertain tax positions are expected to settle within one year. Open tax years by major jurisdictions are: • United States 2012 — 2015 • Germany 2011 — 2015 • Russia 2010 — 2015 The Company currently has an ongoing audit of its German subsidiary's tax filings for the years 2011-2013.

Geographic And Product Informat

Geographic And Product Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Geographic And Product Information	GEOGRAPHIC AND PRODUCT INFORMATION The Company markets and sells its products throughout the world through both direct sales and distribution channels. The geographic sources of the Company's net sales based on billing addresses of its customers are as follows: Year Ended December 31, 2015 2014 2013 United States and other North America $ 131,525 $ 113,233 $ 116,935 Europe: Germany 93,802 77,404 65,147 Other including Eastern Europe/CIS 189,123 173,018 140,279 Asia and Australia: Japan 76,033 72,573 67,981 China 311,946 245,102 192,134 Other 95,494 85,426 64,346 Rest of World 3,342 3,076 1,212 Total $ 901,265 $ 769,832 $ 648,034 Sales are derived from products for different applications: fiber lasers, diode lasers and diodes for materials processing, fiber lasers and amplifiers for advanced applications, fiber amplifiers for communications applications, and fiber lasers for medical applications. Net sales for these product lines are as follows: Year Ended December 31, 2015 2014 2013 Materials Processing $ 849,335 $ 731,274 $ 608,702 Other applications 51,931 38,558 39,332 Total $ 901,265 $ 769,832 $ 648,034 One customer comprised 13% of net sales during the year ended December 31, 2015 and 11% of net sales during the years ended December 31, 2014 and 2013 . 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 25% , 23% and 21% in 2015 , 2014 and 2013 , respectively. The geographic locations of the Company's long-lived assets, net, based on physical location of the assets, as of December 31, 2015 , 2014 and 2013 , are as follows: December 31, 2015 2014 2013 United States $ 170,981 $ 155,428 $ 110,441 Germany 53,678 51,528 52,791 Russia 55,150 59,612 73,747 China 6,237 6,582 5,895 Other 12,045 12,507 13,480 $ 298,091 $ 285,657 $ 256,354 Long lived assets include property, plant and equipment and demonstration equipment.

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Selected Quarterly Financial Data (Unaudited)	SELECTED QUARTERLY FINANCIAL DATA (UNAUDITED) 2015 First Quarter Second Quarter Third Quarter Fourth Quarter (In thousands, except per share data) Net sales $ 198,960 $ 235,138 $ 243,541 $ 223,626 Gross profit 107,827 128,703 133,304 122,043 Net income attributable to IPG Photonics Corporation 57,359 61,299 62,792 60,704 Basic earnings per share 1.09 1.16 1.19 1.15 Diluted earnings per share 1.08 1.15 1.18 1.14 2014 First Quarter Second Quarter Third Quarter Fourth Quarter (In thousands, except per share data) Net sales $ 170,575 $ 192,204 $ 199,651 $ 207,402 Gross profit 89,284 104,227 109,090 113,917 Net income attributable to IPG Photonics Corporation 40,531 48,283 55,200 56,431 Basic earnings per share 0.78 0.93 1.06 1.08 Diluted earnings per share 0.77 0.92 1.05 1.07

Nature Of Business And Summar24

Nature Of Business And Summary Of Significant Accounting Policies (Policy)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Principles of Consolidation	Principles of Consolidation — The Company was incorporated as a Delaware corporation in December 1998. 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	Cash and Cash Equivalents and Short-Term Investments — Cash and cash equivalents consist primarily of highly liquid investments, such as bank deposits, marketable securities with original maturities of three months or less with insignificant interest rate risk and marketable securities with remaining maturities of three months or less at the date of acquisition.
Investment, Policy	Short-term investments consist primarily of similar highly liquid investments and marketable securities with insignificant interest rate risk and with original maturities greater than three months but less than one year.
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. Because of the Company's vertical integration, a significant or sudden decrease in sales activity could result in a significant change in the estimates of excess or obsolete inventory valuation. The costs associated with provisions for excess quantities, technological obsolescence, or component rejections are charged to cost of sales as incurred.
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. The following table presents the assigned economic useful lives of property, plant and equipment: Category Economic Useful Life Buildings 30 years Machinery and equipment 5-12 years Office furniture and fixtures 3-5 years Expenditures for maintenance and repairs are charged to operations. Interest expense associated with significant capital projects is capitalized as a cost of the project.
Long-Lived Assets	Long-Lived Assets — Long-lived assets, which consist primarily of property, plant and equipment, are reviewed by management for impairment whenever events or changes in circumstances indicate that the carrying amount may not be recoverable. In cases in which 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. No impairment losses have been recorded during the periods presented. Included in other long-term assets is certain demonstration equipment. The demonstration equipment is amortized over the respective estimated economic lives, generally 3 years .
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. 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.
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 five to ten years or over the period the economic benefits of the intangible asset are consumed.
Revenue Recognition	Revenue Recognition — The Company recognizes revenue in accordance with ASC 605. Revenue from orders with multiple deliverables is divided into separate units of accounting when certain criteria are met. These separate units generally consist of equipment and installation. The consideration for the arrangement is allocated to the separate units of accounting based on their relative selling prices. The selling price of equipment is based on vendor-specific objective evidence which is the sales price of equipment sold without installation. The selling price of installation is based on third-party evidence which is the fair value of installation services offered by third parties. Revenue for laser and amplifier sources generally is recognized upon the transfer of ownership which is typically at the time of shipment. Installation revenue is recognized upon completion of the installation service which typically occurs within 30 to 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. Returns and customer credits are infrequent and are recorded as a reduction to revenue. Rights of return generally are not included in sales arrangements.
Accounts Receivable and Allowance For Doubtful Accounts	Accounts Receivable and Allowance for Doubtful Accounts — Accounts Receivable include $24,307 and $25,150 of bank acceptance drafts at December 31, 2015 and 2014 , respectively. Bank acceptance drafts are bank guarantees of payment on specified dates. The maturity of these bank acceptance drafts is less than 90 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.
Warranties	Warranties — The Company typically provides one to three -year parts and service warranties on lasers and amplifiers. Most of the Company's sales offices provide support to customers in their respective geographic areas. The Company estimates the warranty accrual considering past claims experience, the number of units still covered by warranty and the average life of the remaining warranty period. The warranty accrual has generally been sufficient to cover product warranty repair and replacement costs.
Stock-Based Compensation	Stock-Based Compensation — The Company accounts for stock-based compensation in accordance with ASC 718. Under the fair value recognition provision of ASC 718, the Company accounts for stock-based compensation 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 uses historical data to estimate pre-vesting option and restricted stock unit forfeitures and record stock-based compensation expense in its statements of income only for those options and awards that are expected to vest. The Company estimates forfeitures at the time of grant and revise these estimates, if necessary, in subsequent periods if actual forfeitures differ from the estimates. 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. The description of the Company's stock-based employee compensation plans and the assumptions it uses to calculate the fair value of stock-based employee compensation is more fully described in Note 2.
Advertising Expense	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 our 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.
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 carryforwards and credits 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 by it 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-term investments, auction rate securities and accounts receivable. The Company maintains substantially all of its cash, short-term investments and marketable securities in six 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 provide a reserve for potential credit losses. Such losses historically have been within management's expectations (see discussion related to significant customers in Note 15).
Fair Value of Financial Instruments	Fair Value of Financial Instruments — 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 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 cash equivalents, short-term investments, 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 these instruments or as a result of the competitive market interest rates, which have been negotiated. The following table presents information about the Company's assets and liabilities measured at fair value: Fair Value Measurements at December 31, 2015 Total Level 1 Level 2 Level 3 Assets Cash equivalents $ 214,232 $ 214,232 $ — $ — Short-term investments 106,375 106,375 — — Auction rate securities 1,136 — — 1,136 Total assets $ 321,743 $ 320,607 $ — $ 1,136 Liabilities Collateralized long-term note $ 19,667 $ 19,667 $ — $ — Contingent purchase consideration $ 20 $ — $ — $ 20 Total liabilities $ 19,687 $ 19,667 $ — $ 20 Fair Value Measurements at December 31, 2014 Total Level 1 Level 2 Level 3 Assets Cash equivalents $ 266,011 $ 266,011 $ — $ — Auction rate securities 1,128 — — 1,128 Total assets $ 267,139 $ 266,011 $ — $ 1,128 Liabilities Collateralized long-term note $ 21,667 $ 21,667 $ — $ — Contingent purchase consideration $ 98 $ — $ — $ 98 Interest rate swap 151 — 151 — Total liabilities $ 21,916 $ 21,667 $ 151 $ 98 Short-term investments are measured and recorded at book value as unrealized gains or losses are not adjusted since they are considered held-to-maturity and consist of liquid investments including U.S. government and government agency notes, corporate notes, commercial paper and certificates of deposit with original maturities of greater than three months but less than one year. The fair value of these investments at December 31, 2015 was $106,375 which represents an unrealized loss of $209 as compared to the $106,584 recorded on the Consolidated Balance Sheets as of December 31, 2015. 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 secondary markets for the securities held by the Company. The auction rate securities are considered available-for-sale securities. They had a cost basis of $1,450 at December 31, 2015 and December 31, 2014 . The Company previously had a cash flow hedge which was an interest rate swap associated with the U.S. long-term note. The interest rate swap agreement terminated with the note, which matured in June 2015. The fair value amount in the consolidated balance sheet related to the interest rate swap was estimated based on quoted market prices or pricing models using current market rates. The fair value at December 31, 2014 for the interest rate swap considered prices observed in inactive secondary markets for the securities held by the Company. The fair value of contingent consideration was determined using an income approach at the respective business combination dates 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 business combinations that give rise to contingent consideration are more fully described in Note 12.
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 and unrealized gains or losses on derivatives. 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.
Cash Flow Hedges	Cash Flow Hedges — The Company's previous cash flow hedge was an interest rate swap under which it payed fixed rates of interest.
Business Segment Information	Business Segment Information — The Company operates in one segment which involves the design, development, production and distribution of fiber lasers, 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 decision maker, who is the Company's chief executive officer, measures financial performance as a single enterprise and not on legal entity or end market basis. Throughout the year, the chief decision maker allocates capital resources on a project-by-project basis across the Company's entire asset base to maximize profitability without regard to 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 geographic financial information and product lines is provided in Note 15.
Earnings Per Share	Earnings Per Share — The Company computes net income per share in accordance with ASC 260- Earnings Per Share .
Recent Accounting Pronouncements	Recent Accounting Pronouncements — In November, the FASB issued amended guidance that clarifies that in a classified statement of financial position, an entity shall classify deferred tax liabilities and assets as non-current amounts. The new guidance supersedes ASC 740-10-45-5 which required the valuation allowance for a particular tax jurisdiction be allocated between current and non-current deferred tax assets for that tax jurisdiction on a pro rata basis. The new standard will become effective for the Company's fiscal year beginning January 1, 2017. The Company is currently assessing the impact of this amended guidance and the timing of adoption. In May 2014, FASB issued Accounting Standards Update No. 2014-09 ("ASU 2014-09") "Revenue from Contracts with Customers." ASU 2014-09 supersedes the revenue recognition requirements in "Revenue Recognition (Topic 605)", and requires entities to recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled to in exchange for those goods or services. As currently issued and amended, ASU 2014-09 is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period, though early adoption is permitted for annual reporting periods beginning after December 15, 2016. The Company is currently in the process of evaluating the impact of the adoption of ASU 2014-09 on its consolidated financial statements and does not expect it to have a material impact on its financial statements upon adoption.
Subsequent Events	Subsequent Events — The Company has considered the impact of subsequent events through the filing date of these financial statements.

Nature Of Business And Summar25

Nature Of Business And Summary Of Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Economic Useful Lives Of Property, Plant And Equipment	The following table presents the assigned economic useful lives of property, plant and equipment: Category Economic Useful Life Buildings 30 years Machinery and equipment 5-12 years Office furniture and fixtures 3-5 years
Allowance For Doubtful Accounts	Activity related to the allowance for doubtful accounts was as follows: 2015 2014 2013 Balance at January 1 $ 1,890 $ 2,473 $ 2,173 Provision for bad debts, net of recoveries 427 579 323 Uncollectable accounts written off (114 ) (617 ) (31 ) Foreign currency translation (392 ) (545 ) 8 Balance at December 31 $ 1,811 $ 1,890 $ 2,473
Summary Of Product Warranty Activity	Activity related to the warranty accrual was as follows: 2015 2014 2013 Balance at January 1 $ 19,272 $ 14,997 $ 10,714 Provision for warranty accrual 22,808 15,449 11,363 Warranty claims (12,208 ) (9,165 ) (7,405 ) Foreign currency translation and other (1,662 ) (2,009 ) 325 Balance at December 31 $ 28,210 $ 19,272 $ 14,997
Assets And Liabilities Measured At Fair Value	The following table presents information about the Company's assets and liabilities measured at fair value: Fair Value Measurements at December 31, 2015 Total Level 1 Level 2 Level 3 Assets Cash equivalents $ 214,232 $ 214,232 $ — $ — Short-term investments 106,375 106,375 — — Auction rate securities 1,136 — — 1,136 Total assets $ 321,743 $ 320,607 $ — $ 1,136 Liabilities Collateralized long-term note $ 19,667 $ 19,667 $ — $ — Contingent purchase consideration $ 20 $ — $ — $ 20 Total liabilities $ 19,687 $ 19,667 $ — $ 20 Fair Value Measurements at December 31, 2014 Total Level 1 Level 2 Level 3 Assets Cash equivalents $ 266,011 $ 266,011 $ — $ — Auction rate securities 1,128 — — 1,128 Total assets $ 267,139 $ 266,011 $ — $ 1,128 Liabilities Collateralized long-term note $ 21,667 $ 21,667 $ — $ — Contingent purchase consideration $ 98 $ — $ — $ 98 Interest rate swap 151 — 151 — Total liabilities $ 21,916 $ 21,667 $ 151 $ 98
Assets Measured At Fair Value On A Recurring Basis Using Significant Unobservable Inputs	The following table presents information about the Company's movement in Level 3 assets and liabilities measured at fair value: 2015 2014 2013 Auction Rate Securities Balance, January 1 $ 1,128 $ 1,120 $ 1,112 Change in fair value and accretion 8 8 8 Balance, December 31 $ 1,136 $ 1,128 $ 1,120 Contingent Purchase Consideration Balance, January 1 $ 98 $ 375 $ 3,023 Period transactions (50 ) — — Change in fair value and currency fluctuations (28 ) (277 ) (2,648 ) Balance, December 31 $ 20 $ 98 $ 375
Components Of Accumulated Other Comprehensive Income (Loss)	Total components of accumulated other comprehensive loss were as follows: December 31, 2015 2014 Foreign currency translation adjustments $ (181,725 ) $ (112,411 ) Unrealized gain (loss) on derivatives, net of tax of $45 and $67 11 (84 ) Change in carrying value of auction rate securities 232 232 Accumulated other comprehensive loss $ (181,482 ) $ (112,263 )
Fair Value Of Cash Flow Hedges	The fair value amounts in the consolidated balance sheets were: Notional Amounts 1 Other Assets Other Current Liabilities Deferred Income Taxes And Other Long-Term Liabilities December 31, December 31, December 31, December 31, 2015 2014 2015 2014 2015 2014 2015 2014 $ — $ 11,333 $ — $ — $ — $ 151 $ — $ — (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 statements of income for the years ended December 31, 2015 , 2014 and 2013 , related to the Company's previous interest rate swap contract was as follows: Year Ended December 31, 2015 2014 2013 Effective portion recognized in other comprehensive (loss) income, pretax: Interest rate swap $ 304 $ 567 $ 881 Effective portion reclassified from other comprehensive (loss) income to interest expense, pretax: Interest rate swap $ (153 ) $ (295 ) $ (449 ) Ineffective portion recognized in income: Interest rate swap $ — $ — $ —

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	Stock-based compensation is included in the following financial statement captions: Year Ended December 31, 2015 2014 2013 Cost of sales $ 5,316 $ 4,153 $ 3,187 Sales and marketing 1,998 1,567 1,195 Research and development 4,049 3,033 1,929 General and administrative 7,626 6,419 5,409 Total stock-based compensation 18,989 15,172 11,720 Tax benefit recognized (6,141 ) (4,865 ) (3,784 ) Net stock-based compensation $ 12,848 $ 10,307 $ 7,936
Summary of Stock Option Activity	The assumptions used in the Black-Scholes model or the calculation of compensation were as follows for the years ended December 31. 2015 2014 2013 Expected term 4.4-6.3 years 4.7-6.1 years 4.4-6.3 years Volatility 45%-48% 48%-51% 51%-54% Risk-free rate of return 1.38%-1.74% 1.46%-1.84% 0.74%-1.32% Dividend yield 0.25% 0.25% 0.25% Forfeiture rate 3.47%-5.88% 3.04%-5.86% 0%-5.97%
Summary Of Option Activity	A summary of option activity is presented below (see Note 11 for further information): Number of Options Weighted- Average Exercise Price Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2015 2,488,350 $ 45.48 Granted 223,694 96.56 Exercised (447,705 ) 28.28 Forfeited (40,170 ) 60.38 Outstanding — December 31, 2015 2,224,169 $ 53.82 6.20 $ 80,292 Vested or expected to vest — December 31, 2015 2,137,468 $ 52.91 6.12 $ 78,937 Exercisable — December 31, 2015 1,050,513 $ 36.24 4.70 $ 55,592
Summary of Restricted Stock Unit Activity	The following table summarizes the restricted stock units ("RSU's") activity for the year ended December 31, 2015 : Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2015 203,526 $ 62.44 Granted 120,365 95.25 Converted (41,487 ) 57.67 Canceled (4,685 ) 71.05 Outstanding — December 31, 2015 277,719 $ 77.22 8.25 24,761,000 $ 24,761 Vested or expected to vest — December 31, 2015 251,143 $ 76.65 8.22 22,392,000 $ 22,392
Summary of Performance Units Fair Value Assessment	The weighted-average fair value of these performance units was determined using the Monte Carlo simulation model incorporating the following weighted-average assumptions: 2015 Expected term 3.2 years Volatility 12%-36% Risk-free rate of return 0.98% Dividend yield —% Weighted-average fair value per share 128.42
Summary of Performance Stock Unit Activity	The following table summarizes the performance stock units ("PSU's") activity for the year ended December 31, 2015 : Number of Shares Weighted-Average Grant-Date Fair Value Weighted- Average Remaining Contractual Life Aggregate Intrinsic Value (In years) (In thousands) Outstanding — January 1, 2015 — $ — Granted 27,233 128.54 Converted Canceled Outstanding — December 31, 2015 27,233 $ 128.54 9.15 $ 2,428 Vested or expected to vest — December 31, 2015 24,366 $ 128.54 9.15 $ 2,172

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Components Of Inventories	Inventories consist of the following: December 31, 2015 2014 Components and raw materials $ 70,394 $ 54,925 Work-in-process 43,259 58,603 Finished goods 90,085 57,481 Total $ 203,738 $ 171,009

Property, Plant And Equipment (

Property, Plant And Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Components Of Property, Plant And Equipment	Property, plant, and equipment consist of the following: December 31, 2015 2014 Land $ 18,962 $ 19,248 Buildings 166,784 144,629 Machinery and equipment 226,724 202,075 Office furniture and fixtures 26,981 25,816 Construction-in-progress 35,946 47,285 Total property, plant and equipment 475,397 439,053 Accumulated depreciation (186,793 ) (163,971 ) Total property, plant and equipment — net $ 288,604 $ 275,082

Accrued Expenses And Other Li29

Accrued Expenses And Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Payables and Accruals [Abstract]
Components Of Accrued Expenses And Other Liabilities	Accrued expenses and other liabilities consist of the following: December 31, 2015 2014 Accrued compensation $ 33,617 $ 31,673 Customer deposits and deferred revenue 21,525 16,605 Current portion of accrued warranty 14,871 9,489 Other 5,654 6,290 Total $ 75,667 $ 64,057

Financing Arrangements (Tables)

Financing Arrangements (Tables)	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Borrowings Under Existing Financing Arrangements	The Company's borrowings under existing financing arrangements consist of the following: December 31, 2015 2014 Revolving line of credit facilities: European overdraft facilities $ — $ 828 Euro line of credit — 1,803 Total $ — $ 2,631 Term debt: U.S. long-term note $ — $ 11,333 Collateralized long-term note 19,667 21,667 Less: current portion (2,000 ) (13,333 ) Total long-term debt $ 17,667 $ 19,667

Net Income Attributable To IP31

Net Income Attributable To IPG Photonics Corporation Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Computation Of Diluted Net Income Per Share	The following table sets forth the computation of diluted net income attributable to IPG Photonics Corporation per share: Year Ended December 31, 2015 2014 2013 Net income attributable to IPG Photonics Corporation $ 242,154 $ 200,445 $ 155,780 Net income attributable to common stockholders 242,154 200,445 155,780 Weighted average shares 52,676 52,104 51,548 Dilutive effect of common stock equivalents 751 720 827 Diluted weighted average common shares 53,427 52,824 52,375 Basic net income attributable to IPG Photonics Corporation per share $ 4.60 $ 3.85 $ 3.02 Basic net income attributable to common stockholders $ 4.60 $ 3.85 $ 3.02 Diluted net income attributable to IPG Photonics Corporation per share $ 4.53 $ 3.79 $ 2.97 Diluted net income attributable to common stockholders $ 4.53 $ 3.79 $ 2.97

Commitments And Contingencies (

Commitments And Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments Under Noncancelable Lease Agreements	Commitments under the noncancelable lease agreements as of December 31, 2015 are as follows: Years Ending December 31 Facilities Equipment Total 2016 $ 2,843 $ 850 $ 3,693 2017 1,983 538 2,521 2018 1,477 327 1,804 2019 1,191 53 1,244 2020 322 15 337 Thereafter — — — Total $ 7,816 $ 1,783 $ 9,599

Goodwill And Intangibles (Table

Goodwill And Intangibles (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Changes In The Carrying Amount Of Goodwill	The following table sets forth the changes in the carrying amount of goodwill for the years ended December 31, 2015 and 2014 : December 31, 2015 December 31, 2014 Balance at January 1 $ 455 $ 455 Foreign exchange adjustment (14 ) — Total goodwill arising from purchase 64 — Balance at December 31 $ 505 $ 455
Intangible Assets	Intangible assets, subject to amortization, consisted of the following: December 31, 2015 December 31, 2014 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Gross Carrying Amount Accumulated Amortization Net Carrying Amount Weighted- Average Lives Patents $ 6,641 $ (4,573 ) $ 2,068 6 Years $ 6,641 $ (4,221 ) $ 2,420 6 Years Customer relationships 3,325 (3,092 ) 233 5 Years 3,660 (3,308 ) 352 5 Years Production know-how 6,672 (3,339 ) 3,333 8 Years 6,844 (2,630 ) 4,214 8 Years Technology, trademark and tradename 8,247 (1,977 ) 6,270 8 Years 3,315 (1,074 ) 2,241 8 Years $ 24,885 $ (12,981 ) $ 11,904 $ 20,460 $ (11,233 ) $ 9,227
Estimated Future Amortization Expense For Intangibles	The estimated future amortization expense for intangibles as of December 31, 2015 is as follows: 2016 2017 2018 2019 2020 Thereafter Total $2,377 $2,239 $2,175 $2,122 $1,374 $1,617 $11,904

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income (Loss) Before Impact Of Income Taxes	Income before the impact of income taxes for the years ended December 31 consisted of the following: 2015 2014 2013 U.S. $ 94,242 $ 72,800 $ 59,006 Foreign 247,375 211,674 159,295 Total $ 341,617 $ 284,474 $ 218,301
Provision For Income Taxes	The Company's provision for income taxes for the years ended December 31 consisted of the following: 2015 2014 2013 Current: Federal $ (30,334 ) $ (22,549 ) $ (19,285 ) State (6,616 ) (2,823 ) (2,617 ) Foreign (69,793 ) (60,143 ) (46,787 ) Total current $ (106,743 ) $ (85,515 ) $ (68,689 ) Deferred: Federal $ 6,303 $ 454 $ 3,834 State 312 27 203 Foreign 538 1,005 2,131 Total deferred $ 7,153 $ 1,486 $ 6,168 Provision for income taxes $ (99,590 ) $ (84,029 ) $ (62,521 )
Reconciliation Of Effective Tax Rate	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, is as follows: 2015 2014 2013 Tax at statutory rate $ (119,566 ) $ (99,867 ) $ (76,406 ) Non-U.S. rate differential — net 15,931 14,590 10,761 State income taxes — net (2,094 ) (1,787 ) (1,512 ) Effect of changes in enacted tax rates on deferred tax assets and liabilities (153 ) (44 ) 186 Nondeductible stock compensation expense (338 ) (483 ) (101 ) Other nondeductible expenses (1,039 ) (2,063 ) (1,666 ) Federal and state tax credits 8,837 5,865 7,500 Change in reserves, including interest and penalties (1,522 ) (7 ) (1,273 ) Change in valuation allowance (620 ) — — Other — net 974 (233 ) (10 ) $ (99,590 ) $ (84,029 ) $ (62,521 )
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, are as follows: 2015 2014 2013 Property, plant and equipment $ (8,031 ) $ (5,310 ) $ (2,230 ) Inventory provisions 14,566 10,497 8,261 Allowances and accrued liabilities 2,590 1,570 3,634 Other tax credits 3,763 726 769 Deferred compensation 5,891 4,218 (434 ) Net operating loss carryforwards 923 — 229 Valuation allowance (678 ) — — Net deferred tax assets $ 19,024 $ 11,701 $ 10,229
Reconciliation Of Unrecognized Tax Benefits	The following is a tabular reconciliation of the total amounts of unrecognized tax benefits: 2015 2014 2013 Balance at January 1 $ 6,494 $ 6,501 $ 5,392 Change in prior period positions 33 (795 ) (505 ) Additions for tax positions in current period 1,052 788 1,614 Balance at December 31 $ 7,579 $ 6,494 $ 6,501
Open Tax Years By Major Jurisdictions	Open tax years by major jurisdictions are: • United States 2012 — 2015 • Germany 2011 — 2015 • Russia 2010 — 2015

Geographic And Product Inform35

Geographic And Product Information (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Geographic Sources Of Net Sales Based On Billing Addresses Of Customers	The geographic sources of the Company's net sales based on billing addresses of its customers are as follows: Year Ended December 31, 2015 2014 2013 United States and other North America $ 131,525 $ 113,233 $ 116,935 Europe: Germany 93,802 77,404 65,147 Other including Eastern Europe/CIS 189,123 173,018 140,279 Asia and Australia: Japan 76,033 72,573 67,981 China 311,946 245,102 192,134 Other 95,494 85,426 64,346 Rest of World 3,342 3,076 1,212 Total $ 901,265 $ 769,832 $ 648,034
Net Sales For Product Lines	Net sales for these product lines are as follows: Year Ended December 31, 2015 2014 2013 Materials Processing $ 849,335 $ 731,274 $ 608,702 Other applications 51,931 38,558 39,332 Total $ 901,265 $ 769,832 $ 648,034
Geographic Locations Of Long-Lived Assets, Based On Physical Location Of Assets	The geographic locations of the Company's long-lived assets, net, based on physical location of the assets, as of December 31, 2015 , 2014 and 2013 , are as follows: December 31, 2015 2014 2013 United States $ 170,981 $ 155,428 $ 110,441 Germany 53,678 51,528 52,791 Russia 55,150 59,612 73,747 China 6,237 6,582 5,895 Other 12,045 12,507 13,480 $ 298,091 $ 285,657 $ 256,354

Selected Quarterly Financial 36

Selected Quarterly Financial Data (Tables)	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Information [Abstract]
Components Of Selected Quarterly Financial Data	2015 First Quarter Second Quarter Third Quarter Fourth Quarter (In thousands, except per share data) Net sales $ 198,960 $ 235,138 $ 243,541 $ 223,626 Gross profit 107,827 128,703 133,304 122,043 Net income attributable to IPG Photonics Corporation 57,359 61,299 62,792 60,704 Basic earnings per share 1.09 1.16 1.19 1.15 Diluted earnings per share 1.08 1.15 1.18 1.14 2014 First Quarter Second Quarter Third Quarter Fourth Quarter (In thousands, except per share data) Net sales $ 170,575 $ 192,204 $ 199,651 $ 207,402 Gross profit 89,284 104,227 109,090 113,917 Net income attributable to IPG Photonics Corporation 40,531 48,283 55,200 56,431 Basic earnings per share 0.78 0.93 1.06 1.08 Diluted earnings per share 0.77 0.92 1.05 1.07

Nature Of Business And Summar37

Nature Of Business And Summary Of Significant Accounting Policies (Narrative) (Details)	12 Months Ended
	Dec. 31, 2015USD ($)segmentFinancial_Institution	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment, interest cost capitalization	$ 0	$ 383,000	$ 524,000
Carrying value of demonstration equipment	298,091,000	285,657,000	256,354,000
Bank acceptance drafts included in Accounts Receivable	$ 24,307,000	25,150,000
Maturity period for bank acceptance drafts	90 days
Accrued warranty reported in accrued expenses and other liabilities	$ 14,871,000	9,489,000
Accrued warranty reported in other long-term liabilities	$ 13,339,000	9,783,000
Percentage of tax positions to be measured at greatest amount of tax benefit	50.00%
High-credit, quality financial institutions | Financial_Institution	6
Held-to-maturity securities, current	$ 106,375,000
Short-term investments	106,584,000	0
Available-for-sale securities	$ 1,450,000	1,450,000
Number of operating segments | segment	1
Not Designated as Hedging Instrument
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Outstanding derivative contracts	$ 0
Demonstration Equipment
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Demonstration equipment, useful life (years)	3 years
Carrying value of demonstration equipment	$ 3,229,000	3,612,000
Amortization expenses of equipment	$ 2,345,000	2,068,000	2,725,000
Minimum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Period for installation completion	30 days
Standard product warranty coverage period	1 year
Minimum | Intangible Assets
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Economic lives of intangible assets	5 years
Maximum
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Period for installation completion	90 days
Standard product warranty coverage period	3 years
Maximum | Intangible Assets
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Economic lives of intangible assets	10 years
Property, Plant and Equipment
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Property, plant and equipment impairment or disposal disclosure	$ 0	$ 0	$ 0
Held-to-maturity Securities
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Marketable securities, unrealized gain (loss)	$ 209,000

Nature Of Business And Summar38

Nature Of Business And Summary Of Significant Accounting Policies (Economic Useful Lives Of Property, Plant And Equipment) (Details)	12 Months Ended
	Dec. 31, 2015
Buildings
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful life	30 years
Minimum | Machinery and equipment
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful life	5 years
Minimum | Office furniture and fixtures
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful life	3 years
Maximum | Machinery and equipment
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful life	12 years
Maximum | Office furniture and fixtures
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Useful life	5 years

Nature Of Business And Summar39

Nature Of Business And Summary Of Significant Accounting Policies (Allowance For Doubtful Accounts) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at January 1	$ 1,890	$ 2,473	$ 2,173
Provision for bad debts, net of recoveries	427	579	323
Uncollectable accounts written off	(114)	(617)	(31)
Foreign currency translation	(392)	(545)	(8)
Balance at December 31	$ 1,811	$ 1,890	$ 2,473

Nature Of Business And Summar40

Nature Of Business And Summary Of Significant Accounting Policies (Activity Related To The Warranty Accrual) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at January 1	$ 19,272	$ 14,997	$ 10,714
Provision for warranty accrual	22,808	15,449	11,363
Warranty claims	(12,208)	(9,165)	(7,405)
Foreign currency translation and other	(1,662)	(2,009)	325
Balance at December 31	$ 28,210	$ 19,272	$ 14,997

Nature Of Business And Summar41

Nature Of Business And Summary Of Significant Accounting Policies (Assets And Liabilities Measured At Fair Value) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Assets
Total assets	$ 321,743	$ 267,139
Liabilities
Total liabilities	19,687	21,916
Level 1
Assets
Total assets	320,607	266,011
Liabilities
Total liabilities	19,667	21,667
Level 2
Liabilities
Total liabilities	0	151
Level 3
Assets
Total assets	1,136	1,128
Liabilities
Total liabilities	20	98
Cash equivalents
Assets
Total assets	214,232	266,011
Cash equivalents | Level 1
Assets
Total assets	214,232	266,011
Short-term investments
Assets
Total assets	106,375
Short-term investments | Level 1
Assets
Total assets	106,375
Auction rate securities
Assets
Total assets	1,136	1,128
Auction rate securities | Level 3
Assets
Total assets	1,136	1,128
Collateralized Long Term Note
Liabilities
Total liabilities	19,667	21,667
Collateralized Long Term Note | Level 1
Liabilities
Total liabilities	19,667	21,667
Contingent purchase consideration
Liabilities
Total liabilities	20	98
Contingent purchase consideration | Level 2
Liabilities
Total liabilities		0
Contingent purchase consideration | Level 3
Liabilities
Total liabilities	$ 20	98
Interest rate swap
Liabilities
Total liabilities		151
Interest rate swap | Level 2
Liabilities
Total liabilities		151
Interest rate swap | Level 3
Liabilities
Total liabilities		$ 0

Nature Of Business And Summar42

Nature Of Business And Summary Of Significant Accounting Policies (Assets Measured At Fair Value On A Recurring Basis Using Significant Unobservable Inputs) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Auction Rate Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, January 1	$ 1,128	$ 1,120	$ 1,112
Change in fair value and accretion	8	8	8
Balance, December 31	1,136	1,128	1,120
Contingent Purchase Consideration
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, January 1	98	375	3,023
Change in fair value and accretion	(28)	(277)	(2,648)
Period transactions	(50)	0	0
Balance, December 31	$ 20	$ 98	$ 375

Nature Of Business And Summar43

Nature Of Business And Summary Of Significant Accounting Policies (Components Of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Foreign currency translation adjustments	$ (181,725)	$ (112,411)
Unrealized gain (loss) on derivatives, net of tax of $45 and $67	11	(84)
Change in carrying value of auction rate securities	232	232
Accumulated other comprehensive loss	(181,482)	(112,263)
Unrealized gain (loss) on derivatives, net of tax of $45 and $67	$ 45	$ 67

Nature Of Business And Summar44

Nature Of Business And Summary Of Significant Accounting Policies (Fair Value Of Cash Flow Hedges) (Details) - Interest rate swap - USD ($) $ in Thousands		Dec. 31, 2015	Dec. 31, 2014
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Notional amount of derivatives	[1]	$ 0	$ 11,333
Other Assets
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Derivative asset fair value		0	0
Other Current Liabilities
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Derivative liability fair value	[2]	0	151
Deferred Income Taxes And Other Long-Term Liabilities
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Derivative liability fair value	[2]	$ 0	$ 0
[1]	Notional amounts represent the gross contract/notional amount of the derivative outstanding.
[2]	{F|ahBzfndlYmZpbGluZ3MtaHJkcmoLEgZYTUxEb2MiXlhCUkxEb2NHZW5JbmZvOmE3ZjM1NDZhMmQ1NTQwOWE4ZmM4MDI4Y2QwNjIxM2E5fFRleHRTZWxlY3Rpb246RDk5OUI1NENFQUI5QTQ4NzRFOTdENDM5MEIyNzJERkQM}

Nature Of Business And Summar45

Nature Of Business And Summary Of Significant Accounting Policies (Derivative Gains And Losses In The Consolidated Statements Of Income) (Details) - Interest rate swap - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Nature Of Business And Summary Of Significant Accounting Policies [Line Items]
Effective portion recognized in other comprehensive (loss) income, pretax:	$ 304	$ 567	$ 881
Effective portion reclassified from other comprehensive (loss) income to interest expense, pretax:	(153)	(295)	(449)
Ineffective portion recognized in income:	$ 0	$ 0	$ 0

Stock-Based Compensation (Compo

Stock-Based Compensation (Components Of Stock Based Compensation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 18,989	$ 15,172	$ 11,720
Tax benefit recognized	(6,141)	(4,865)	(3,784)
Net stock-based compensation	12,848	10,307	7,936
Cost of sales
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	5,316	4,153	3,187
Sales and marketing
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	1,998	1,567	1,195
Research and development
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	4,049	3,033	1,929
General and administrative
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Total stock-based compensation	$ 7,626	$ 6,419	$ 5,409

Stock-Based Compensation (Weigh

Stock-Based Compensation (Weighted Average Assumptions) (Details)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Volatility, minimum	45.00%	48.00%	51.00%
Volatility, maximum	48.00%	51.00%	54.00%
Risk free rate of return, minimum	1.38%	1.46%	0.74%
Risk free rate of return, maximum	1.74%	1.84%	1.32%
Dividend yield	0.25%	0.25%	0.25%
Forfeiture rate, minimum	3.47%	3.04%	0.00%
Forfeiture rate, maximum	5.88%	5.86%	5.97%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	4 years 4 months 24 days	4 years 8 months 12 days	4 years 4 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected term	6 years 3 months 18 days	6 years 1 month 6 days	6 years 3 months 18 days

Stock-Based Compensation (Summa

Stock-Based Compensation (Summary Of Option Activity) (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Number of Options Outstanding, Beginning Balance | shares	2,488,350
Number of Options, Granted | shares	223,694
Number of Options, Exercised | shares	(447,705)
Number of Options, Forfeited | shares	(40,170)
Number of Options Outstanding, Ending Balance | shares	2,224,169
Number of Options, Vested or expected to vest | shares	2,137,468
Number of Options, Exercisable | shares	1,050,513
Weighted-Average Exercise Price, Outstanding, Beginning Balance | $ / shares	$ 45.48
Weighted-Average Exercise Price, Granted | $ / shares	96.56
Weighted-Average Exercise Price, Exercised | $ / shares	28.28
Weighted-Average Exercise Price, Forfeited | $ / shares	60.38
Weighted-Average Exercise Price, Outstanding, Ending Balance | $ / shares	53.82
Weighted-Average Exercise Price, Vested or expected to vest | $ / shares	52.91
Weighted-Average Exercise Price, Exercisable | $ / shares	$ 36.24
Weighted-Average Remaining Contractual Life (In Years), Outstanding	6 years 2 months 12 days
Weighted-Average Remaining Contractual Life (In Years), Vested or expected to vest	6 years 1 month 13 days
Weighted-Average Remaining Contractual Life (In Years), Exercisable	4 years 8 months 12 days
Aggregate Intrinsic Value, Outstanding | $	$ 80,292
Aggregate Intrinsic Value, Vested or expected to vest | $	78,937
Aggregate Intrinsic Value, Exercisable | $	$ 55,592

Stock-Based Compensation (Narra

Stock-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2015shares	Dec. 31, 2015USD ($)plan$ / sharesshares	Dec. 31, 2014USD ($)$ / shares	Dec. 31, 2013USD ($)$ / shares	Dec. 31, 2011shares	Jun. 30, 2006shares	Feb. 28, 2006shares	Apr. 30, 2000shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of plans | plan		3
Intrinsic value of options exercised | $		$ 27,207	$ 20,474	$ 29,473
Weighted-average grant fair value for options granted | $ / shares		$ 42.78	$ 32.53	$ 28.28
Compensation cost related to nonvested awards not yet recorded | $		$ 17,009
Nonvested awards, weighted average recognition period		2 years 2 months 12 days
Fair value of awards vested | $		$ 12,034
2000 Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved under plan								5,833,333
Shares available for future grant		0
2006 Incentive Compensation Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved under plan					6,084,273		4,000,000
Shares reserved under plan, authorized but unissued					84,273
Shares reserved, previously authorized under prior plan	194,919
Shares available for future grant		5,078,138
Non Employee Directors Stock Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved under plan						486,660
Shares available for future grant		0
Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		1 year
Period until expiration		7 years
Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period		5 years
Period until expiration		10 years
Restricted Stock Units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost related to nonvested awards not yet recorded | $		$ 11,856
Nonvested awards, weighted average recognition period		2 years 7 months 6 days
Fair value of awards vested | $		$ 2,393
Share-based compensation arrangement by share-based payment award, equity instruments other than options, exercises in period, intrinsic value | $		$ 3,705	$ 3,017	$ 590
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period, weighted average grant date fair value | $ / shares		$ 95.25	$ 69.22	$ 59.40
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, target goal, percentage		100.00%
Compensation cost related to nonvested awards not yet recorded | $		$ 2,467
Nonvested awards, weighted average recognition period		3 years 2 months 12 days
Share-based compensation arrangement by share-based payment award, equity instruments other than options, grants in period, weighted average grant date fair value | $ / shares		$ 128.54
Performance Shares | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, awarded units earned, percentage		0.00%
Performance Shares | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, awarded units earned, percentage		200.00%

Stock-Based Compensation (Sum50

Stock-Based Compensation (Summary of Restricted Stock Unit Activity) (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Number of of Units, Outstanding, Beginning Balance		203,526
Number of Units, Granted		120,365
Number of Units, Exercised		(41,487)
Number of Units, Cancelled		(4,685)
Number of Units, Outstanding, Ending Balance	277,719	277,719	203,526
Number of Units, Vested or Expected to Vest	251,143	251,143
Weighted-Average Grant-Date Fair Value, Units Outstanding, Beginning Balance		$ 62.44
Weighted-Average Grant-Date Fair Value, Units Granted		95.25	$ 69.22	$ 59.40
Weighted-Average Grant-Date Fair Value, Units Exercised		57.67
Weighted-Average Grant-Date Fair Value, Units Cancelled		71.05
Weighted-Average Grant-Date Fair Value, Units Outstanding, Ending Balance	$ 77.22	$ 77.22	$ 62.44
Weighted-Average Grant-Date Fair Value, Units Vested or Expected to Vest	$ 76.65
Weighted-Average Remaining Contractual Life (In Years), Outstanding		8 years 3 months
Weighted-Average Remaining Contractual Life (In Years), Vested or expected to vest		8 years 2 months 19 days
Aggregate Intrinsic Value, Outstanding	$ 24,761	$ 24,761
Aggregate Intrinsic Value, Vested or expected to vest	$ 22,392

Stock-Based Compensation (Sum51

Stock-Based Compensation (Summary of Performance Stock Unit Activity) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Dividend yield		0.25%	0.25%	0.25%
Volatility Rate, Minimum		45.00%	48.00%	51.00%
Volatility Rate, Maximum		48.00%	51.00%	54.00%
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Number of of Units, Outstanding, Beginning Balance		0
Number of Units, Granted		27,233
Number of Units, Outstanding, Ending Balance	27,233	27,233	0
Number of Units, Vested or Expected to Vest	24,366	24,366
Weighted-Average Grant-Date Fair Value, Units Outstanding, Beginning Balance		$ 0
Weighted-Average Grant-Date Fair Value, Units Granted		128.54
Weighted-Average Grant-Date Fair Value, Units Outstanding, Ending Balance	$ 128.54	$ 128.54	$ 0
Weighted-Average Grant-Date Fair Value, Units Vested or Expected to Vest	$ 128.54
Weighted-Average Remaining Contractual Life (In Years), Outstanding		9 years 1 month 24 days
Weighted-Average Remaining Contractual Life (In Years), Vested or expected to vest		9 years 1 month 24 days
Aggregate Intrinsic Value, Outstanding	$ 2,428	$ 2,428
Aggregate Intrinsic Value, Vested or expected to vest	$ 2,172
Expected term		3 years 2 months 12 days
Risk-free rate of return		0.98%
Dividend yield		0.00%
Weighted-average fair value per share	$ 128.42	$ 128.42
Volatility Rate, Minimum		12.00%
Volatility Rate, Maximum		36.00%
Minimum
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Expected term		4 years 4 months 24 days	4 years 8 months 12 days	4 years 4 months 24 days
Maximum
Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding [Roll Forward]
Expected term		6 years 3 months 18 days	6 years 1 month 6 days	6 years 3 months 18 days

Inventories (Components Of Inve

Inventories (Components Of Inventories) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Components and raw materials	$ 70,394	$ 54,925
Work-in-process	43,259	58,603
Finished goods	90,085	57,481
Total	203,738	171,009
Inventory provisions	$ 15,364	$ 11,302	$ 15,128

Property, Plant And Equipment53

Property, Plant And Equipment (Components Of Property, Plant, And Equipment) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 475,397	$ 439,053
Accumulated depreciation	(186,793)	(163,971)
Total property, plant and equipment — net	288,604	275,082
Depreciation expense	37,796	31,334	$ 26,489
Land
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	18,962	19,248
Buildings
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	166,784	144,629
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	226,724	202,075
Office furniture and fixtures
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	26,981	25,816
Construction-in-progress
Property, Plant and Equipment [Line Items]
Total property, plant and equipment	$ 35,946	$ 47,285

Accrued Expenses And Other Li54

Accrued Expenses And Other Liabilities (Components Of Accrued Expenses And Other Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Payables and Accruals [Abstract]
Accrued compensation	$ 33,617	$ 31,673
Customer deposits and deferred revenue	21,525	16,605
Current portion of accrued warranty	14,871	9,489
Other	5,654	6,290
Total	$ 75,667	$ 64,057

Financing Arrangements (Borrowi

Financing Arrangements (Borrowings Under Existing Financing Arrangements) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Revolving line of credit facilities:
Total drawings under credit facility	$ 0	$ 2,631
Term debt:
Less: current portion	(2,000)	(13,333)
Total long-term debt	17,667	19,667
European overdraft facilities
Revolving line of credit facilities:
Total drawings under credit facility	0	828
Euro line of credit
Revolving line of credit facilities:
Total drawings under credit facility	0	1,803
U.S. long-term note
Revolving line of credit facilities:
Total drawings under credit facility	$ 0	11,333
Collateralized long-term note
Revolving line of credit facilities:
Total drawings under credit facility		$ 21,667

Financing Arrangements (Narrati

Financing Arrangements (Narrative) (Details)	1 Months Ended	12 Months Ended
	Oct. 31, 2014USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2015EUR (€)credit_line	Dec. 31, 2015USD ($)credit_line	Dec. 31, 2014USD ($)
Line of Credit Facility [Line Items]
Total drawings under credit facility				$ 0	$ 2,631,000
Long Term Note
Line of Credit Facility [Line Items]
Total drawings under credit facility				19,667,000
Interest rate percentage	2.81%
Monthly principal payments	$ 167,000
U.S. Line Of Credit
Line of Credit Facility [Line Items]
Aggregate available principal under credit facility				50,000
Total drawings under credit facility				0
Guarantor obligations, maximum exposure, undiscounted				2,828,000
Aggregate remaining availability				47,172
U.S. long-term note
Line of Credit Facility [Line Items]
Debt service coverage ratio		1.5
Euro Line Of Credit
Line of Credit Facility [Line Items]
Aggregate available principal under credit facility			€ 30,000,000	32,719,000
Total drawings under credit facility				0
Guarantor obligations, maximum exposure, undiscounted				8,221,000
Aggregate remaining availability				24,498,000
Euro Overdraft Facilities
Line of Credit Facility [Line Items]
Aggregate available principal under credit facility			500,000	545,000
Total drawings under credit facility				0
Aggregate remaining availability				545,000
European overdraft facilities
Line of Credit Facility [Line Items]
Aggregate available principal under credit facility			€ 1,500,000	1,636,000
Total drawings under credit facility				0
Aggregate remaining availability				$ 1,636,000
Number of credit lines | credit_line			2	2
Minimum | U.S. long-term note
Line of Credit Facility [Line Items]
Debt Instrument, covenant compliance		$ 50,000,000
Maximum | U.S. long-term note
Line of Credit Facility [Line Items]
Debt Instrument, covenant compliance		$ 250,000,000
London Interbank Offered Rate (LIBOR) | Minimum | U.S. Line Of Credit
Line of Credit Facility [Line Items]
Percentage over LIBOR		0.80%
London Interbank Offered Rate (LIBOR) | Maximum | U.S. Line Of Credit
Line of Credit Facility [Line Items]
Percentage over LIBOR		1.20%

Noncontrolling Interest and S57

Noncontrolling Interest and Stockholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 15, 2015
Noncontrolling Interest [Line Items]
Net income (loss) attributable to NCI	$ (127)	$ 0	$ 0
Common stock, shares authorized	175,000,000	175,000,000
Common stock, par value	$ 0.0001	$ 0.0001
Preferred stock, shares authorized	5,000,000
Preferred stock, par value	$ 0.0001
Shares of preferred stock outstanding	0
RuchTech
Noncontrolling Interest [Line Items]
Percentage of noncontrolling interest				76.00%

Related-Party Transactions (Det

Related-Party Transactions (Details) ft² in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2014	Dec. 31, 2015USD ($)ft²director	Dec. 31, 2014USD ($)director
Director
Related Party Transaction [Line Items]
Related party revenue		$ 146,000
Purchased Parts and Services from Company which Independent Director is Executive Officer
Related Party Transaction [Line Items]
Number of directors | director		1	1
Payments to suppliers		$ 683,000	$ 3,687,000
Purchased Parts and Services from Company which Independent Director is Executive Officer | Equipment
Related Party Transaction [Line Items]
Related party transaction, due from (to) related party		5,873,000
Purchased Parts and Services from Company which Independent Director is Executive Officer | Director
Related Party Transaction [Line Items]
Accounts payable due to company		$ 0	0
Leased Office Space | CEO and Chairman of the Board | Office space
Related Party Transaction [Line Items]
Area of office space | ft²		12
Annual lease payments		$ 794
Annual increase in lease payments (percentage)		2.50%
Amount paid in transaction		$ 531,000	20,000
Leased Aircraft | CEO and Chairman of the Board | Aircraft
Related Party Transaction [Line Items]
Annual lease payments		651,000
Amount paid in transaction		$ 651,000	146,000
Percentage of aircraft	25.00%
Products and Services sold to Affiliated Entity | CEO and Chairman of the Board
Related Party Transaction [Line Items]
Ownership percentage in Laser Center		39.00%
Related party revenue		$ 497,000	$ 2,731,000

Net Income Attributable To IP59

Net Income Attributable To IPG Photonics Corporation Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options excluded from computation of diluted weighted average common shares									29,127,000	46,987,000	322,301,000
Net income attributable to IPG Photonics Corporation	$ 60,704	$ 62,792	$ 61,299	$ 57,359	$ 56,431	$ 55,200	$ 48,283	$ 40,531	$ 242,154	$ 200,445	$ 155,780
Net income attributable to common stockholders									$ 242,154	$ 200,445	$ 155,780
Weighted average shares (in shares)									52,676,000	52,104,000	51,548,000
Dilutive effect of common stock equivalents (in shares)									751,000	720,000	827,000
Diluted weighted average common shares									53,427,000	52,824,000	52,375,000
Basic net income attributable to IPG Photonics Corporation per share (in dollars per share)									$ 4.60	$ 3.85	$ 3.02
Basic net income attributable to common stockholders (in dollars per share)	$ 1.15	$ 1.19	$ 1.16	$ 1.09	$ 1.08	$ 1.06	$ 0.93	$ 0.78	4.60	3.85	3.02
Diluted net income attributable to IPG Photonics Corporation per share (in dollars per share)									4.53	3.79	2.97
Diluted net income attributable to common stockholders (in dollars per share)	$ 1.14	$ 1.18	$ 1.15	$ 1.08	$ 1.07	$ 1.05	$ 0.92	$ 0.77	$ 4.53	$ 3.79	$ 2.97
Restricted Stock Units (RSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options excluded from computation of diluted weighted average common shares									18,171,000	13,300,000	6,635,000
Phantom Share Units (PSUs)
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Options excluded from computation of diluted weighted average common shares									3,369,000	0	0

Commitments And Contingencies60

Commitments And Contingencies (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Feb. 26, 2016
Other Commitments [Line Items]
Operating lease, rent expense	$ 7,365,000	$ 5,516,000	$ 4,560,000
Purchase obligations	17,961,000	22,288,000
Loss contingency, loss in period	$ 0
Members of senior management
Other Commitments [Line Items]
Period for terms of employment agreement	3 years
Agreement to purchase certain intellectual property and know-how related to laser based systems
Other Commitments [Line Items]
Purchase obligations		$ 4,500,000
RuchTech | Agreement to purchase certain intellectual property and know-how related to laser based systems
Other Commitments [Line Items]
Noncontrolling interest, ownership percentage by parent		76.00%
Subsequent Event
Other Commitments [Line Items]
Loss contingency, loss in period				$ 0

Commitments and Contingencies61

Commitments and Contingencies (Commitments Under Noncancelable Lease Agreements) (Details) $ in Thousands	Dec. 31, 2015USD ($)
Operating Leased Assets [Line Items]
2,016	$ 3,693
2,017	2,521
2,018	1,804
2,019	1,244
2,020	337
Thereafter	0
Total	9,599
Facilities
Operating Leased Assets [Line Items]
2,016	2,843
2,017	1,983
2,018	1,477
2,019	1,191
2,020	322
Thereafter	0
Total	7,816
Equipment
Operating Leased Assets [Line Items]
2,016	850
2,017	538
2,018	327
2,019	53
2,020	15
Thereafter	0
Total	$ 1,783

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
401 (K) Retirement Savings Plan
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Percentage of matching contribution by employee	50.00%
Percentage of eligible compensation for employee contribution	6.00%
Compensation Expense	$ 2,021	$ 1,445	$ 1,127
Employee Stock Purchase Plan
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Percentage of discount on stock purchase price	15.00%
Purchase period	6 months
Maximum percentage of payroll deduction of employees compensation	10.00%
Compensation expense related to employee stock purchase plan	$ 680	$ 607	$ 498
Shares available for issuance	356,344

Business Combinations (Details)

Business Combinations (Details) - USD ($) $ in Thousands	Mar. 15, 2015	Mar. 13, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Acquired Finite-Lived Intangible Assets [Line Items]
Goodwill balance			$ 505	$ 455	$ 455
RuchTech
Acquired Finite-Lived Intangible Assets [Line Items]
Business acquisition, percentage of voting interests acquired	76.00%		76.00%
Business combination, acquisition of less than 100 percent, noncontrolling interest, fair value	$ 6,579
Business combination, consideration transferred	$ 5,000
Acquired finite-lived intangible asset			$ 6,298
Estimated useful life	7 years
Goodwill balance			$ 64
RuchTech | Technology-Based Intangible Assets
Acquired Finite-Lived Intangible Assets [Line Items]
Business combination, recognized identifiable assets acquired and liabilities assumed, finite-lived intangibles	$ 6,298
Mobius Photonics
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired finite-lived intangible asset		$ 4,480
Estimated useful life			7 years
Goodwill balance	$ 505

Goodwill And Intangibles (Chang

Goodwill And Intangibles (Changes In The Carrying Amount Of Goodwill) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill [Roll Forward]
Balance at January 1	$ 455	$ 455
Foreign exchange adjustment		0
Total goodwill arising from purchase		0
Balance at December 31	505	$ 455
RuchTech
Goodwill [Roll Forward]
Foreign exchange adjustment	(14)
Total goodwill arising from purchase	64
Balance at December 31	$ 64

Goodwill And Intangibles (Narra

Goodwill And Intangibles (Narrative) (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 15, 2015
Business Acquisition [Line Items]
GOODWILL		$ 505,000	$ 455,000	$ 455,000
Total goodwill arising from purchase			0
Goodwill adjustment			0
Amortization expense of intangibles		2,274,000	$ 2,210,000	$ 2,310,000
Patents
Business Acquisition [Line Items]
Acquired finite-lived intangible asset	$ 2,000,000
RuchTech
Business Acquisition [Line Items]
GOODWILL		64,000
Total goodwill arising from purchase		64,000
Goodwill adjustment		$ (14,000)
Business acquisition, percentage of voting interests acquired		76.00%			76.00%
Business acquisition, goodwill, expected tax deductible amount		$ 0
Acquired finite-lived intangible asset		$ 6,298,000
Domestic Tax Authority
Business Acquisition [Line Items]
Goodwill, deductibility time period		15 years

Goodwill And Intangibles (Intan

Goodwill And Intangibles (Intangible Assets) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 24,885	$ 20,460
Accumulated Amortization	(12,981)	(11,233)
Net Carrying Amount	11,904	9,227
Patents
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	6,641	6,641
Accumulated Amortization	(4,573)	(4,221)
Net Carrying Amount	$ 2,068	$ 2,420
Weighted- Average Lives	6 years	6 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,325	$ 3,660
Accumulated Amortization	(3,092)	(3,308)
Net Carrying Amount	$ 233	$ 352
Weighted- Average Lives	5 years	5 years
Production know-how
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 6,672	$ 6,844
Accumulated Amortization	(3,339)	(2,630)
Net Carrying Amount	$ 3,333	$ 4,214
Weighted- Average Lives	8 years	8 years
Technology, trademark and tradename
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 8,247	$ 3,315
Accumulated Amortization	(1,977)	(1,074)
Net Carrying Amount	$ 6,270	$ 2,241
Weighted- Average Lives	8 years	8 years

Goodwill And Intangibles (Estim

Goodwill And Intangibles (Estimated Future Amortization Expense For Intangibles) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
2,016	$ 2,377
2,017	2,239
2,018	2,175
2,019	2,122
2,020	1,374
Thereafter	1,617
Net Carrying Amount	$ 11,904	$ 9,227

Income Taxes (Income (Loss) Bef

Income Taxes (Income (Loss) Before Impact Of Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
U.S.	$ 94,242	$ 72,800	$ 59,006
Foreign	247,375	211,674	159,295
INCOME BEFORE PROVISION FOR INCOME TAXES	$ 341,617	$ 284,474	$ 218,301

Income Taxes (Provision For Inc

Income Taxes (Provision For Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current:
Federal	$ (30,334)	$ (22,549)	$ (19,285)
State	(6,616)	(2,823)	(2,617)
Foreign	(69,793)	(60,143)	(46,787)
Total current	(106,743)	(85,515)	(68,689)
Deferred:
Federal	6,303	454	3,834
State	312	27	203
Foreign	538	1,005	2,131
Total deferred	7,153	1,486	6,168
Provision for income taxes	$ (99,590)	$ (84,029)	$ (62,521)

Income Taxes (Reconciliation Of

Income Taxes (Reconciliation Of Effective Tax Rate) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Tax at statutory rate	$ (119,566)	$ (99,867)	$ (76,406)
Non-U.S. rate differential — net	15,931	14,590	10,761
State income taxes — net	(2,094)	(1,787)	(1,512)
Effect of changes in enacted tax rates on deferred tax assets and liabilities	(153)	(44)	186
Nondeductible stock compensation expense	(338)	(483)	(101)
Other nondeductible expenses	(1,039)	(2,063)	(1,666)
Federal and state tax credits	8,837	5,865	7,500
Change in reserves, including interest and penalties	(1,522)	(7)	(1,273)
Change in valuation allowance	(620)	0	0
Other — net	974	(233)	(10)
Provision for income taxes	$ (99,590)	$ (84,029)	$ (62,521)

Income Taxes (Deferred Tax Asse

Income Taxes (Deferred Tax Assets And Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Property, plant and equipment	$ (8,031)	$ (5,310)	$ (2,230)
Inventory provisions	14,566	10,497	8,261
Allowances and accrued liabilities	2,590	1,570	3,634
Other tax credits	3,763	726	769
Deferred compensation	5,891	4,218	(434)
Net operating loss carryforwards	923	0	229
Valuation allowance	(678)	0	0
Net deferred tax assets	$ 19,024	$ 11,701	$ 10,229

Income Taxes (Narrative) (Detai

Income Taxes (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Tax Credit Carryforward [Line Items]
Cumulative unremitted earnings that are reinvested	$ 734,000,000	$ 522,000,000
Estimated penalties and interest related to the underpayment of income taxes	437,000	(192,000)	$ 374,000
Accrued penalties and interest related to the underpayment of income taxes	1,107,000	670,000
UK | Foreign Tax Authority
Tax Credit Carryforward [Line Items]
Net operating loss carry-forwards available for future periods		2,509,000
State
Tax Credit Carryforward [Line Items]
Tax credit carry forward amount	$ 3,740,000	$ 1,225,000	$ 2,074,000

Income Taxes (Reconciliation 73

Income Taxes (Reconciliation Of Unrecognized Tax Benefits) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 6,494	$ 6,501	$ 5,392
Change in prior period positions	33	(795)	(505)
Additions for tax positions in current period	1,052	788	1,614
Balance at December 31	$ 7,579	$ 6,494	$ 6,501

Income Taxes (Open Tax Years By

Income Taxes (Open Tax Years By Major Jurisdictions) (Details)	12 Months Ended
	Dec. 31, 2015
Minimum | United States
Income Tax Contingency [Line Items]
Open tax years by major jurisdictions	2,012
Minimum | Germany
Income Tax Contingency [Line Items]
Open tax years by major jurisdictions	2,011
Minimum | Russia
Income Tax Contingency [Line Items]
Open tax years by major jurisdictions	2,010
Maximum | United States
Income Tax Contingency [Line Items]
Open tax years by major jurisdictions	2,015
Maximum | Germany
Income Tax Contingency [Line Items]
Open tax years by major jurisdictions	2,015
Maximum | Russia
Income Tax Contingency [Line Items]
Open tax years by major jurisdictions	2,015

Geographic And Product Inform75

Geographic And Product Information (Geographic Sources Of Net Sales Based On Billing Addresses Of Customers) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Geographic And Product Information [Line Items]
Net sales	$ 223,626	$ 243,541	$ 235,138	$ 198,960	$ 207,402	$ 199,651	$ 192,204	$ 170,575	$ 901,265	$ 769,832	$ 648,034
United States and other North America
Geographic And Product Information [Line Items]
Net sales									131,525	113,233	116,935
Germany
Geographic And Product Information [Line Items]
Net sales									93,802	77,404	65,147
Other including Eastern Europe/CIS
Geographic And Product Information [Line Items]
Net sales									189,123	173,018	140,279
Japan
Geographic And Product Information [Line Items]
Net sales									76,033	72,573	67,981
China
Geographic And Product Information [Line Items]
Net sales									311,946	245,102	192,134
Other
Geographic And Product Information [Line Items]
Net sales									95,494	85,426	64,346
Rest of World
Geographic And Product Information [Line Items]
Net sales									$ 3,342	$ 3,076	$ 1,212

Geographic And Product Inform76

Geographic And Product Information (Net Sales For Product Lines) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Product Information [Line Items]
Net sales	$ 223,626	$ 243,541	$ 235,138	$ 198,960	$ 207,402	$ 199,651	$ 192,204	$ 170,575	$ 901,265	$ 769,832	$ 648,034
Materials Processing
Product Information [Line Items]
Net sales									849,335	731,274	608,702
Other applications
Product Information [Line Items]
Net sales									$ 51,931	$ 38,558	$ 39,332

Geographic And Product Inform77

Geographic And Product Information (Narrative) (Details) - Cusotmer	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Concentration Risk [Line Items]
Number of customers	1		1
Number of largest customers, sales	5
Net sales by largest customers, percentage	25.00%	23.00%	21.00%
Sales
Concentration Risk [Line Items]
Concentration risk percentage	13.00%	11.00%	11.00%

Geographic And Product Inform78

Geographic And Product Information (Geographic Locations Of Our Long-Lived Assets, Based On Physical Location Of Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Geographic And Product Information [Line Items]
Long-lived assets	$ 298,091	$ 285,657	$ 256,354
United States
Geographic And Product Information [Line Items]
Long-lived assets	170,981	155,428	110,441
Germany
Geographic And Product Information [Line Items]
Long-lived assets	53,678	51,528	52,791
Russia
Geographic And Product Information [Line Items]
Long-lived assets	55,150	59,612	73,747
China
Geographic And Product Information [Line Items]
Long-lived assets	6,237	6,582	5,895
Other
Geographic And Product Information [Line Items]
Long-lived assets	$ 12,045	$ 12,507	$ 13,480

Selected Quarterly Financial 79

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, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Information [Abstract]
Net sales	$ 223,626	$ 243,541	$ 235,138	$ 198,960	$ 207,402	$ 199,651	$ 192,204	$ 170,575	$ 901,265	$ 769,832	$ 648,034
Gross profit	122,043	133,304	128,703	107,827	113,917	109,090	104,227	89,284	491,877	416,518	339,898
Net income attributable to IPG Photonics Corporation	$ 60,704	$ 62,792	$ 61,299	$ 57,359	$ 56,431	$ 55,200	$ 48,283	$ 40,531	$ 242,154	$ 200,445	$ 155,780
Basic earnings per share	$ 1.15	$ 1.19	$ 1.16	$ 1.09	$ 1.08	$ 1.06	$ 0.93	$ 0.78	$ 4.60	$ 3.85	$ 3.02
Diluted earnings per share	$ 1.14	$ 1.18	$ 1.15	$ 1.08	$ 1.07	$ 1.05	$ 0.92	$ 0.77	$ 4.53	$ 3.79	$ 2.97