MKS Instruments (MKSI) 10-K 26 Feb 16 2015 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2015	Feb. 19, 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 Year Focus	2,015
Document Fiscal Period Focus	FY
Trading Symbol	MKSI
Entity Registrant Name	MKS INSTRUMENTS INC
Entity Central Index Key	1,049,502
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		53,242,650
Entity Public Float			$ 2,024,748,115

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 227,574	$ 305,437
Short-term investments	430,663	286,795
Trade accounts receivable, net of allowance for doubtful accounts of $1,760 and $2,250 at December 31, 2015 and 2014, respectively	101,883	106,362
Inventories	152,631	155,169
Deferred income taxes		14,017
Other current assets	26,760	27,512
Total current assets	939,511	895,292
Property, plant and equipment, net	68,856	72,776
Goodwill	199,703	192,381
Intangible assets, net	44,027	46,389
Other assets	21,250	17,206
Total assets	1,273,347	1,224,044
Current liabilities:
Accounts payable	23,177	34,166
Accrued compensation	28,424	26,970
Income taxes payable	4,024	6,702
Other current liabilities	35,359	35,789
Total current liabilities	90,984	103,627
Other liabilities	$ 21,482	$ 38,595
Commitments and contingencies (Note 23)
Stockholders' equity:
Preferred stock, $0.01 par value, 2,000,000 shares authorized; none issued and outstanding
Common stock, no par value, 200,000,000 shares authorized; 53,199,720 and 53,154,666 shares issued and outstanding at December 31, 2015 and 2014, respectively	$ 113	$ 113
Additional paid-in capital	744,725	734,732
Retained earnings	427,214	349,061
Accumulated other comprehensive loss	(11,171)	(2,084)
Total stockholders' equity	1,160,881	1,081,822
Total liabilities and stockholders' equity	$ 1,273,347	$ 1,224,044

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Allowance for doubtful accounts	$ 1,760	$ 2,250
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, shares authorized	2,000,000	2,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	53,199,720	53,154,666
Common stock, shares outstanding	53,199,720	53,154,666

Consolidated Statements of Oper

Consolidated Statements of Operations and Comprehensive Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net revenues:
Products		$ 697,104	$ 673,819	$ 568,317
Services		116,420	107,050	101,103
Total net revenues		813,524	780,869	669,420
Cost of revenues:
Cost of products		373,764	374,200	337,464
Cost of services		76,888	68,903	65,382
Total cost of revenues (exclusive of amortization shown separately below)		450,652	443,103	402,846
Gross profit		362,872	337,766	266,574
Research and development		68,305	62,888	63,570
Selling, general and administrative		129,087	131,828	142,014
Insurance reimbursement				(1,071)
Acquisition costs		30	499	171
Restructuring		2,074	2,464	1,364
Amortization of intangible assets		6,764	4,945	2,139
Income from operations		156,612	135,142	58,387
Interest income		2,999	1,323	999
Interest expense		143	72	85
Income before income taxes		159,468	136,393	59,301
Provision for income taxes		37,171	20,615	23,525
Net income		122,297	115,778	35,776
Other comprehensive income:
Changes in value of financial instruments designated as cash flow hedges, net of tax (benefit) expense	[1]	(469)	1,210	62
Foreign currency translation adjustments, net of tax of $0 for 2015, 2014 and 2013		(8,301)	(14,707)	(3,604)
Unrealized loss on investments, net of tax benefit	[2]	(317)	(460)	(40)
Total comprehensive income		$ 113,210	$ 101,821	$ 32,194
Net income per share:
Basic		$ 2.30	$ 2.17	$ 0.67
Diluted		2.28	2.16	0.67
Cash dividends paid per common share		$ 0.675	$ 0.655	$ 0.640
Weighted average common shares outstanding:
Basic		53,282	53,232	53,061
Diluted		53,560	53,515	53,481
[1]	Tax (benefit) expense was $(85), $144 and $551 for the years ended December 31, 2015, 2014 and 2013, respectively.
[2]	Tax benefit was $(58), $(55), and $(355) for the years ended December 31, 2015, 2014 and 2013, respectively.

Consolidated Statements of Ope5

Consolidated Statements of Operations and Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Tax (benefit) expense on changes in value of financial instruments designated as cash flow hedges	$ (85)	$ 144	$ 551
Tax on foreign currency translation adjustments	0	0	0
Tax benefit on unrealized loss on investments	$ (58)	$ (55)	$ (355)

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income/(Loss) [Member]
Beginning Balance at Dec. 31, 2012	$ 1,012,156	$ 113	$ 718,005	$ 278,583	$ 15,455
Beginning Balance, Shares at Dec. 31, 2012		52,748,849
Net issuance under stock-based plans	(464)		(464)
Net issuance under stock-based plans, Shares		721,601
Stock-based compensation	13,992		13,992
Tax effect from stock-based plans	495		495
Stock repurchase	(2,875)		(1,457)	(1,418)
Stock repurchase, Shares		(107,000)
Cash dividend	(33,975)			(33,975)
Comprehensive income (net of tax):
Net issuance under stock-based plans	(464)		(464)
Net issuance under stock-based plans, Shares		721,601
Stock-based compensation	13,992		13,992
Tax effect from stock-based plans	495		495
Stock repurchase	(2,875)		(1,457)	(1,418)
Stock repurchase, Shares		(107,000)
Cash dividend	(33,975)			(33,975)
Net income	35,776			35,776
Other comprehensive loss	(3,582)				(3,582)
Ending Balance at Dec. 31, 2013	1,021,523	$ 113	730,571	278,966	11,873
Ending Balance, Shares at Dec. 31, 2013		53,363,450
Ending Balance, Shares at Dec. 31, 2013		53,363,450
Net issuance under stock-based plans	2,492		2,492
Net issuance under stock-based plans, Shares		519,128
Stock-based compensation	11,315		11,315
Tax effect from stock-based plans	331		331
Stock repurchase	$ (20,809)		(9,977)	(10,832)
Stock repurchase, Shares	(727,912)	(727,912)
Cash dividend	$ (34,851)			(34,851)
Comprehensive income (net of tax):
Net issuance under stock-based plans	2,492		2,492
Net issuance under stock-based plans, Shares		519,128
Stock-based compensation	11,315		11,315
Tax effect from stock-based plans	331		331
Stock repurchase	$ (20,809)		(9,977)	(10,832)
Stock repurchase, Shares	(727,912)	(727,912)
Cash dividend	$ (34,851)			(34,851)
Net income	115,778			115,778
Other comprehensive loss	(13,957)				(13,957)
Ending Balance at Dec. 31, 2014	1,081,822	$ 113	734,732	349,061	(2,084)
Ending Balance, Shares at Dec. 31, 2014		53,154,666
Ending Balance, Shares at Dec. 31, 2014		53,154,666
Net issuance under stock-based plans	1,262		1,262
Net issuance under stock-based plans, Shares		414,187
Stock-based compensation	13,013		13,013
Tax effect from stock-based plans	837		837
Stock repurchase	$ (13,294)		(5,119)	(8,175)
Stock repurchase, Shares	(369,133)	(369,133)
Cash dividend	$ (35,969)			(35,969)
Comprehensive income (net of tax):
Net issuance under stock-based plans	1,262		1,262
Net issuance under stock-based plans, Shares		414,187
Stock-based compensation	13,013		13,013
Tax effect from stock-based plans	837		837
Stock repurchase	$ (13,294)		(5,119)	(8,175)
Stock repurchase, Shares	(369,133)	(369,133)
Cash dividend	$ (35,969)			(35,969)
Net income	122,297			122,297
Other comprehensive loss	(9,087)				(9,087)
Ending Balance at Dec. 31, 2015	$ 1,160,881	$ 113	$ 744,725	$ 427,214	$ (11,171)
Ending Balance, Shares at Dec. 31, 2015		53,199,720
Ending Balance, Shares at Dec. 31, 2015		53,199,720

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	$ 122,297	$ 115,778	$ 35,776
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	22,103	20,514	17,102
Stock-based compensation	13,013	11,315	13,992
Provision for excess and obsolete inventory	13,602	12,131	21,671
Provision for doubtful accounts	(255)	668	631
Deferred income taxes	410	5,264	(3,089)
Excess tax benefits from stock-based compensation	(904)	(447)	(935)
Other	275	139	200
Changes in operating assets and liabilities:
Trade accounts receivable	2,334	6,103	(36,153)
Inventories	(14,501)	(20,910)	(29,797)
Income taxes	(8,462)	(32,744)	24,441
Other current and non-current assets	(1,526)	(325)	1,355
Accrued compensation	3,335	(13,563)	13,677
Other current and non-current liabilities	(2,797)	3,469	(5,956)
Accounts payable	(10,629)	(5,478)	23,172
Net cash provided by operating activities	138,295	101,914	76,087
Cash flows from investing activities:
Acquisition of business, net of cash acquired	(9,910)	(86,950)	(2,326)
Purchases of investments	(385,999)	(360,813)	(550,076)
Maturities of investments	179,285	249,359	417,566
Sales of investments	61,659	185,186	110,928
Purchases of property, plant and equipment	(12,414)	(13,183)	(12,410)
Other	8	1,593	(216)
Net cash used in investing activities	(167,371)	(24,808)	(36,534)
Cash flows from financing activities:
Proceeds from short-term borrowings			6
Payments on short-term borrowings			(776)
Repurchases of common stock	(13,294)	(20,809)	(2,875)
Net proceeds related to employee stock awards	1,262	2,492	(464)
Dividend payments	(35,969)	(34,851)	(33,975)
Excess tax benefit from stock-based compensation	904	447	935
Net cash used in financing activities	(47,097)	(52,721)	(37,149)
Effect of exchange rate changes on cash and cash equivalents	(1,690)	(7,850)	(1,090)
(Decrease) increase in cash and cash equivalents	(77,863)	16,535	1,314
Cash and cash equivalents at beginning of year	305,437	288,902	287,588
Cash and cash equivalents at end of year	227,574	305,437	288,902
Cash paid during the period for:
Interest	34	44	60
Income taxes	$ 43,239	$ 47,948	$ 11,878

Business Description

Business Description	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business Description	1) Business Description MKS Instruments, Inc. (“MKS” or the “Company”) was founded in 1961 and is a global provider of instruments, subsystems and process control solutions that measure, control, power, monitor and analyze critical parameters of advanced manufacturing processes to improve process performance and productivity of advanced manufacturing processes. MKS groups its products into three product groups based upon the similarity of the product function, type of product and manufacturing processes. These three groups of products are: Instruments, Control and Vacuum Products; Power and Reactive Gas Products; and Analytical Solutions Products. MKS’ products are derived from its core competencies in pressure measurement and control, materials delivery, gas composition analysis, control and information technology, power and reactive gas generation and vacuum technology. The Company has four reportable segments: Advanced Manufacturing Capital Equipment, Global Service, Asia Region Sales and Other.

Basis of Presentation

Basis of Presentation	12 Months Ended
	Dec. 31, 2015
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	2) Basis of Presentation The consolidated financial statements include the accounts of MKS Instruments, Inc. and its wholly owned subsidiaries. All intercompany accounts and transactions have been eliminated in consolidation. Use of Estimates The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of these financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going basis, management evaluates its estimates and judgments, including those related to revenue recognition and allowance for doubtful accounts, inventory valuation, warranty costs, stock-based compensation, intangible assets, goodwill, other long-lived assets, in process research and development and other acquisition expenses and income taxes. Management bases its estimates and judgments on historical experience and on various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions. Reclassifications Certain prior year amounts have been reclassified to be consistent with current year classifications. Management has the ability, if necessary, to liquidate any of its investments in order to meet the Company’s liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term on the accompanying balance sheets. This election has resulted in investments with contractual maturities greater than one year from the date of purchase previously presented as long-term investments to be re-classified to short-term investments for the period ended December 31, 2014. The table below reflects the adjustment in the balance sheet line items for the period ended December 31, 2014. December 31, 2014 As previously Adjustment As adjusted Short-term investments $ 129,594 $ 157,201 $ 286,795 Long-term investments $ 157,201 $ (157,201 ) $ — The footnotes that were affected by the adjustment for the period ended December 31, 2014 are discussed as follows: Note 5—The fair value of short-term investments consists of the following: December 31, 2014 Available-for-sale investments: As previously Adjustment As adjusted Time deposits and certificates of deposit $ 20,900 $ 48 $ 20,948 Bankers acceptance drafts 82 — 82 Asset-backed securities — 75,674 75,674 Corporate obligations 24,020 64,669 88,689 Municipal bonds 2,099 1,254 3,353 U.S. agency obligations 82,493 15,556 98,049 $ 129,594 $ 157,201 $ 286,795 Short-term investments within the tables that reflect the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments as of December 31, 2014 (Note 5) and assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2014 (Note 6) include all investments, including those investments that were presented as long-term investments as of December 31, 2014, to be consistent with the 2015 presentation.

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	3) Summary of Significant Accounting Policies Revenue Recognition and Accounts Receivable Allowances Revenue from product sales is recorded upon transfer of title and risk of loss to the customer provided that there is evidence of an arrangement, the sales price is fixed or determinable, and collection of the related receivable is reasonably assured. In most transactions, the Company has no obligations to customers after the date products are shipped other than pursuant to warranty obligations. In some instances, the Company provides installation, training, support and services to customers after the product has been shipped. The Company does not frequently enter into arrangements with multiple deliverables; however, for those revenue arrangements with multiple deliverables, the Company allocates revenue to each element based upon its relative selling price using vendor-specific objective evidence (“VSOE”), or third-party evidence (“TPE”) or based upon the relative selling price using estimated prices if VSOE or TPE does not exist. The Company then recognizes revenue on each deliverable in accordance with its policies for product and service revenue recognition. The Company provides for the estimated costs to fulfill customer warranty obligations upon the recognition of the related revenue. Shipping and handling fees, if any, billed to customers are recognized as revenue. The related shipping and handling costs are recognized in cost of revenues. Accounts receivable allowances include sales returns and bad debt allowances. The Company monitors and tracks the amount of product returns and reduces revenue at the time of shipment for the estimated amount of such future returns, based on historical experience. The Company makes estimates evaluating its allowance for doubtful accounts. The Company continuously monitors collections and payments from its customers and maintains a provision for estimated credit losses based upon its historical experience and any specific customer collection issues that it has identified. Research and Development Research and development costs are expensed as incurred and consist mainly of compensation-related expenses and project materials. The Company’s research and development efforts include numerous projects, which generally have a duration of 3 to 30 months. Acquired in-process research and development (“IPR&D”) expenses, which are capitalized at fair value as an intangible asset until the related project is completed, are then amortized over the estimated useful life of the product. The Company monitors projects and, if they are abandoned, the Company immediately writes them off. Advertising Costs Advertising costs are expensed as incurred and were immaterial in 2015, 2014 and 2013. Stock-Based Compensation The accounting for share-based compensation expense requires the measurement and recognition of compensation expense for all share-based payment awards made to employees and directors based on estimated fair values. For restricted stock units (“RSUs”), the fair value is the fair value on the date of grant that normally vest over a three year period. The Company also provides employees the opportunity to purchase shares through an employee stock purchase plan. For shares issued under its employee stock purchase plan, the Company has estimated the fair value on the date of grant using the Black Scholes pricing model, which is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include the Company’s expected stock price volatility over the term of the awards, expected life, risk free interest rate and expected dividends. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Management determined that blended volatility, a combination of historical and implied volatility, is more reflective of market conditions and a better indicator of expected volatility than historical or implied volatility alone. The assumptions used in calculating the fair value of share-based payment awards represent management’s best estimates, but these 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. Accumulated Other Comprehensive Income For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the year. Translation adjustments resulting from this process are recorded to Accumulated Other Comprehensive Income (“OCI”). Unrealized gains and losses on securities classified as available-for-sale are included in OCI in consolidated stockholders’ equity. For derivative instruments designated as cash-flow hedges, the effective portion of the derivative’s gain (loss) is initially reported as a component of OCI and is subsequently recognized in earnings when the hedged exposure is recognized in earnings. Net Income Per Share Basic net income per share is based on the weighted average number of common shares outstanding, and diluted net income per share is based on the weighted average number of common shares outstanding and all potential dilutive common equivalent shares outstanding. The dilutive effect of options is determined under the treasury stock method using the average market price for the period. Common equivalent shares are included in the per share calculations when the effect of their inclusion would be dilutive. Cash and Cash Equivalents and Investments All highly liquid investments with a maturity date of three months or less at the date of purchase are considered to be cash equivalents. The appropriate classification of investments in securities is determined at the time of purchase. Debt securities that the Company does not have the intent and ability to hold to maturity are classified as “available-for-sale” and are carried at fair value. Effective December 31, 2015, the Company changed the method of classification of its investments previously classified as long-term investments to short-term investments within current assets and the balances for the prior year have been reclassified to conform to the current year’s presentation. This new method classifies these securities as current or long-term based on the nature of the securities and the availability for use in current operations while the prior classification was based on the maturity dates of the investments. The Company believes this method is preferable because it is more reflective of the Company’s assessment of its overall liquidity position. The Company reviews its investment portfolio on a quarterly basis to identify and evaluate individual investments that have indications of possible impairment. The factors considered in determining whether a loss is other-than-temporary include: the length of time and extent to which fair market value has been below the cost basis, the financial condition and near-term prospects of the issuer, credit quality, and the Company’s ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in fair value. Concentrations of Credit Risk The Company’s significant concentrations of credit risk consist principally of cash and cash equivalents, investments, forward exchange contracts and trade accounts receivable. The Company maintains cash and cash equivalents with financial institutions including some banks with which it had borrowings. The Company maintains investments primarily in U.S. Treasury and government agency securities and corporate debt securities. The Company enters into forward currency contracts with high credit-quality financial institutions in order to minimize credit risk exposure. The Company’s customers are primarily concentrated in the semiconductor industry, and a limited number of customers account for a significant portion of the Company’s revenues. The Company regularly monitors the creditworthiness of its customers and believes it has adequately provided for potential credit loss exposures. Credit is extended for all customers based primarily on financial condition, and collateral is not required. The Company had one customer comprising 18%, 19% and 17% of net revenues for 2015, 2014 and 2013, respectively, and another customer comprising 13%, 13% and 12% of net revenues for 2015, 2014, and 2013, respectively. During the years 2015, 2014 and 2013, approximately 69%, 70% and 68% of the Company’s net revenues, respectively, were from sales to semiconductor capital equipment manufacturers and semiconductor device manufacturers. There were two customers comprising 10% or more of the Company’s accounts receivable balance as of December 31, 2015. Inventories Inventories are stated at the lower of cost or market, cost being determined using a standard costing system which approximates cost based on a first-in, first-out method. The Company regularly reviews inventory quantities on hand and records a provision to write-down excess and obsolete inventory to its estimated net realizable value, if less than cost, based primarily on its estimated forecast of product demand. Property, Plant and Equipment Property, plant and equipment are stated at cost. Expenditures for major renewals and betterments that extend the useful lives of property, plant and equipment are capitalized. Expenditures for maintenance and repairs are charged to expense as incurred. When assets are sold or otherwise disposed of, the cost and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is recognized in earnings. Depreciation is provided on the straight-line method over the estimated useful lives of twenty to thirty-one and one-half years for buildings and three to seven years for machinery and equipment, furniture and fixtures and office equipment, which includes enterprise resource planning software. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the leased asset. Intangible Assets Intangible assets resulting from the acquisitions of businesses are estimated by management based on the fair value of assets acquired. These include acquired customer lists, technology, patents, trade names, covenants not to compete and IPR&D. Intangible assets are amortized from two to ten years on a straight-line basis which represents the estimated periods of benefit and the expected pattern of consumption. Goodwill Goodwill is the amount by which the cost of acquired net assets exceeded the fair value of those net assets on the date of acquisition. The Company allocates goodwill to reporting units at the time of acquisition or when there is a change in the reporting structure and bases that allocation on which reporting units will benefit from the acquired assets and liabilities. Reporting units are defined as operating segments or one level below an operating segment, referred to as a component. In 2015, the Company reallocated its goodwill based upon a change in its reporting structure. There was no goodwill impairment as a result of this change in reporting units. The Company assesses goodwill for impairment on an annual basis as of October 31 or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. The estimated fair value of the Company’s reporting units were based on discounted cash flow models derived from internal earnings and internal and external market forecasts. Determining fair value requires the exercise of significant judgment, including judgments about appropriate discount rates, perpetual growth rates and the amount and timing of expected future cash flows. Discount rates are based on a weighted average cost of capital (“WACC”), which represents the average rate a business must pay its providers of debt and equity. The WACC used to test goodwill is derived from a group of comparable companies. Assumptions in estimating future cash flows are subject to a high degree of judgment and complexity. The Company makes every effort to forecast these future cash flows as accurately as possible with the information available at the time the forecast is developed. The Company has the option of first assessing qualitative factors to determine whether it is necessary to perform the current two-step impairment test or the Company can perform the two-step impairment test without performing the qualitative assessment. For the reporting units that did not experience any significant adverse changes in their business or reporting structures or any other adverse changes, and the reporting unit’s fair value substantially exceeded its amount from the prior year assessment, the Company performed the qualitative “Step 0” assessment. In performing the qualitative Step 0 assessment, the Company considered certain events and circumstances specific to the reporting unit and to the entity as a whole, such as macroeconomic conditions, industry and market considerations, overall financial performance and cost factors when evaluating whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. For the remaining reporting units that did not meet these criteria, the Company performed the two-step goodwill impairment test. Under the two-step goodwill impairment test, the Company compared the fair value of each reporting unit to its respective carrying amount, including goodwill. If the fair value of the reporting unit exceeds the fair value, the second step of the goodwill impairment test must be completed to measure the amount of impairment loss, if any. The second step compares the implied fair value of goodwill with the carrying value of goodwill. The implied fair value is determined by allocating the fair value of the reporting unit to all of the assets and liabilities of that unit, the excess of the fair value of the amounts assigned to its assets and liabilities it the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount of goodwill, an impairment loss is recognized equal to the difference. As of October 31, 2015, the Company performed its annual impairment assessment of goodwill and determined that it is more likely than not that the fair values of the reporting units exceed their carrying amount. Impairment of Long-Lived Assets The Company evaluates the recoverability of its long-lived assets whenever events and changes in circumstances indicate that the carrying amount of an asset may not be fully recoverable. This periodic review may result in an adjustment of estimated depreciable lives or asset impairment. When indicators of impairment are present, the carrying values of the asset are evaluated in relation to their operating performance and future undiscounted cash flows of the underlying business. If the future undiscounted cash flows are less than their carrying value, impairment exists. The impairment is measured as the difference between the carrying value and the fair value of the underlying asset. Fair values are based on estimates of market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk. Foreign Exchange The functional currency of the majority of the Company’s foreign subsidiaries is the applicable local currency. For those subsidiaries, assets and liabilities are translated to U.S. dollars at year-end exchange rates. Income and expense accounts are translated at the average exchange rates prevailing during the year. The resulting translation adjustments are included in accumulated other comprehensive income (loss) in consolidated stockholders’ equity. Foreign exchange transaction gains and losses, which arise from transaction activity, are reflected in selling, general and administrative expenses in the statement of operations. Net foreign exchange gains and losses resulting from re-measurement are included in selling general and administrative expense and were a loss of $1,388, a loss of $314 and a loss of $1,937, respectively, for the years ended December 31, 2015, 2014 and 2013. These amounts do not reflect the corresponding gain (loss) from foreign exchange contracts. See Note 7 “Derivatives” regarding foreign exchange contracts. Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and also for operating loss and tax credit carry-forwards. On a quarterly basis, the Company evaluates both the positive and negative evidence that affects the realizability of net deferred tax assets and assesses the need for a valuation allowance. The future benefit to be derived from its deferred tax assets is dependent upon its ability to generate sufficient future taxable income in each jurisdiction of the right type to realize the assets. The Company records a valuation allowance to reduce its net deferred tax assets to the amount that is more likely than not to be realized. To the extent the Company establishes a valuation allowance an expense will be recorded as a component of the provision for income taxes on the statement of operations. During 2013, the Company decreased its valuation allowance by $395 primarily related to the expiration of U.S. capital loss carry-forwards. As a result, the valuation allowance was $27,102 at December 31, 2013. During 2014, the Company decreased its valuation allowance by $339 primarily related to the effective settlement of a foreign tax audit. As a result, the valuation allowance was $26,763 at December 31, 2014. During 2015, the Company decreased its valuation allowance by $20,636 primarily related to the expiration of U.S. capital loss carry-forwards. As a result, the valuation allowance was $6,127 at December 31, 2015. Accounting for income taxes requires a two-step approach to recognize and measure uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not that the position will be sustained upon audit, including resolutions of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement. The Company re-evaluates these uncertain tax positions on a quarterly basis. This evaluation is based on factors including, but not limited to, changes in facts or circumstances, changes in tax law, effectively settled issues under audit and new audit activity. Any change in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision.

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	12 Months Ended
	Dec. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	4) Recently Issued Accounting Pronouncements In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes.” Current generally accepted accounting principles require an entity to separate deferred income tax liabilities and assets into current and noncurrent amounts in a classified statement of financial position. The new amendments in this ASU require that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. Early application is permitted. The Company prospectively adopted this ASU during the fourth quarter of 2015. Adoption of this ASU did not have a material impact on the Company’s financial position and results of operations. In September 2015, the FASB issued ASU 2015-16, “Business Combinations (Topic 805)—Simplifying the Accounting for Measurement-Period Adjustments.” The new standard requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustments are identified, including the cumulative effect of the change in the provisional amount as if the accounting had been completed at the acquisition date. This ASU is effective for reporting periods beginning after December 15, 2015. Adoption of this ASU could have a material impact on the Company’s financial position and results of operations. In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330)—Simplifying the Measurement of Inventory.” The amendments in this ASU apply to all inventory that is measured using first-in, first-out or average cost. The new standard requires that an entity measure inventory within the scope of this update at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Adoption of this ASU is not expected to have a material impact on the Company’s financial position and results of operations. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” Under the new guidance, management will be required to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. This ASU is not expected to have an impact on the Company’s financial statements or disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. This standard requires a company to recognize revenue when it transfers goods and services to customers in an amount that reflects the consideration that the company expects to be entitled to in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and assets recognized from costs incurred to obtain or fulfill a contract. This pronouncement is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The two permitted transition methods under the new standard are the full retrospective method, in which case the standard would be applied to each prior reporting period presented, or the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company has not yet selected a transition method. The Company is currently evaluating the requirements of ASU 2014-09 and we have not yet determined its impact on the Company’s consolidated financial statements.

Investments

Investments	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investments	5) Investments The fair value of investments classified as short-term consists of the following: Years Ended December 31, Available-for-sale investments: 2015 2014 Time deposits and certificates of deposit $ 11,892 $ 20,948 Bankers acceptance drafts 728 82 Asset-backed securities 124,997 75,674 Corporate obligations 165,109 88,689 Municipal bonds 8,355 3,353 U.S. agency obligations 119,582 98,049 $ 430,663 $ 286,795 The following table shows the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments: As of December 31, 2015: Cost Gross Gross Estimated Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 11,893 $ — $ (1 ) $ 11,892 Bankers acceptance drafts 728 — — 728 Asset-backed securities 125,271 — (274 ) 124,997 Corporate obligations 165,445 5 (341 ) 165,109 Municipal bonds 8,346 13 (4 ) 8,355 U.S. agency obligations 119,699 3 (120 ) 119,582 $ 431,382 $ 21 $ (740 ) $ 430,663 As of December 31, 2014: Cost Gross Gross Estimated Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 20,949 $ — $ (1 ) $ 20,948 Bankers acceptance drafts 82 — — 82 Asset-backed securities 75,778 5 (109 ) 75,674 Corporate obligations 88,871 3 (185 ) 88,689 Municipal bonds 3,357 — (4 ) 3,353 U.S. agency obligations 98,051 16 (18 ) 98,049 $ 287,088 $ 24 $ (317 ) $ 286,795 The table above, which shows the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments as of December 31, 2014, reflects the inclusion of investments with contractual maturities greater than one year from the date of purchase within short-term investments. Management has the ability, if necessary, to liquidate any of its investments in order to meet the Company’s liquidity needs in the next 12 months. Accordingly, those investments with contractual maturities greater than one year from the date of purchase are classified as short-term on the accompanying balance sheets. Interest income is accrued as earned. Dividend income is recognized as income on the date the stock trades “ex-dividend.” The cost of marketable securities sold is determined by the specific identification method and realized gains or losses are reflected in income and was not material in 2015, 2014 and 2013.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	6) Fair Value Measurements In accordance with the provisions of fair value accounting, a fair value measurement assumes that the transaction to sell an asset or transfer a liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability and defines fair value based upon an exit price model. The fair value measurement guidance establishes a fair value hierarchy which requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The guidance describes three levels of inputs that may be used to measure fair value: Level 1 Quoted prices in active markets for identical assets or liabilities as of the reporting date. Active markets are those in which transactions for the asset or liability occur in sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 Observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities; quoted prices in markets that are not active; or other inputs that are observable or can be corroborated by observable market data for substantially the full term of the assets or liabilities. Level 2 assets and liabilities include debt securities with quoted prices that are traded less frequently than exchange-traded instruments or securities or derivative contracts that are valued using a pricing model with inputs that are observable in the market or can be derived principally from or corroborated by observable market data. Level 3 Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the assets or liabilities. Level 3 assets and liabilities include financial instruments whose value is determined using pricing models, discounted cash flow methodologies, or similar techniques, as well as instruments for which the determination of fair value requires significant management judgment or estimation. In certain cases, the inputs used to measure fair value may fall into different levels of the fair value hierarchy. In such cases, the Company categorizes such assets and liabilities based on the lowest level input that is significant to the fair value measurement in its entirety. The Company’s assessment of the significance of a particular input to the fair value measurement in its entirety requires judgment and considers factors specific to the asset. Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2015, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, Quoted Prices in (Level 1) Significant Other (Level 2) Significant (Level 3) Assets: Cash equivalents: Money market funds $ 106,099 $ 106,099 $ — $ — Bankers acceptance drafts 11 — 11 — Corporate obligations 330 — 330 — Available-for-sale investments: Time deposits and certificates of deposit 11,892 — 11,892 — Bankers acceptance drafts 728 — 728 — Asset-backed securities 124,997 — 124,997 — Corporate obligations 165,109 — 165,109 — Municipal bonds 8,355 — 8,355 — U.S. agency obligations 119,582 — 119,582 — Derivatives—currency forward contracts 1,486 — 1,486 — Total assets $ 538,589 $ 106,099 $ 432,490 $ — Liabilities: Derivatives—currency forward contracts $ 263 $ — $ 263 $ — Reported as follows: Assets: Cash and cash equivalents(1) $ 106,440 $ 106,099 $ 341 $ — Short-term investments 430,663 — 430,663 — Other current assets 1,486 — 1,486 — $ 538,589 $ 106,099 $ 432,490 $ — Liabilities: Other current liabilities $ 263 $ — $ 263 $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $110,118 and non-negotiable time deposits of $11,016 as of December 31, 2015. Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2014, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, Quoted Prices in (Level 1) Significant Other (Level 2) Significant (Level 3) Assets: Cash equivalents: Money market funds $ 129,092 $ 129,092 $ — $ — Bankers acceptance drafts 131 — 131 — Corporate obligations 700 — 700 — Available-for-sale investments: Time deposits and certificates of deposit 20,948 — 20,948 — Bankers acceptance drafts 82 — 82 — Asset-backed securities 75,674 — 75,674 — Corporate obligations 88,689 — 88,689 — Municipal bonds 3,353 — 3,353 — U.S. agency obligations 98,049 — 98,049 — Derivatives—currency forward contracts 2,110 — 2,110 — Total assets $ 418,828 $ 129,092 $ 289,736 $ — Liabilities: Derivatives—currency forward contracts $ — $ — $ — $ — Reported as follows: Assets: Cash and cash equivalents(1) $ 129,923 $ 129,092 $ 831 $ — Short-term investments(2) 286,795 — 286,795 — Other current assets 2,110 — 2,110 — $ 418,828 $ 129,092 $ 289,736 $ — Liabilities: Other current liabilities $ — $ — $ — $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $167,517 and non-negotiable time deposits of $7,997 as of December 31, 2014. (2) Short-term investments as of December 31, 2014 includes investments with contractual maturities greater than one year from the date of purchase within short-term investments as management has the ability, if necessary, to liquidate any of its investments in order to meet the Company’s liquidity needs in the next 12 months. Money Market Funds Money market funds are cash and cash equivalents, and are classified within Level 1 of the fair value hierarchy. Available-For-Sale Investments As of December 31, 2015, available-for-sale investments consisted of time deposits and drafts denominated in the Euro currency, certificates of deposit, bankers acceptance drafts, asset-backed securities (which include auto loans, credit card receivables and equipment trust receivables), corporate obligations, municipal bonds and U.S. agency obligations. The Company measures its debt and equity investments at fair value. The Company’s available-for-sale investments are classified within Level 1 and Level 2 of the fair value hierarchy. Derivatives As a result of the Company’s global operating activities, the Company is exposed to market risks from changes in foreign currency exchange rates, which may adversely affect its operating results and financial position. When deemed appropriate, the Company minimizes its risks from foreign currency exchange rate fluctuations through the use of derivative financial instruments. The principal market in which the Company executes its foreign currency contracts is the institutional market in an over-the-counter environment with a relatively high level of price transparency. The market participants usually are large commercial banks. The forward foreign currency exchange contracts are valued using broker quotations, or market transactions and are classified within Level 2 of the fair value hierarchy.

Derivatives

Derivatives	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	7) Derivatives The Company enters into derivative instruments for risk management purposes only, including derivatives designated as hedging instruments and those utilized as economic hedges. The Company operates internationally and, in the normal course of business, is exposed to fluctuations in interest rates and foreign exchange rates. These fluctuations can increase the costs of financing, investing and operating the business. The Company has used derivative instruments, such as forward contracts, to manage certain foreign currency exposure. By nature, all financial instruments involve market and credit risks. The Company enters into derivative instruments with major investment grade financial institutions and no collateral is required. The Company has policies to monitor the credit risk of these counterparties. While there can be no assurance, the Company does not anticipate any material non-performance by any of these counterparties. The Company hedges a portion of its forecasted foreign currency denominated intercompany sales of inventory, over a maximum period of eighteen months, using forward foreign exchange contracts accounted for as cash-flow hedges related to Japanese, South Korean, British, Euro and Taiwanese currencies. To the extent these derivatives are effective in off-setting the variability of the hedged cash flows, and otherwise meet the hedge accounting criteria, changes in the derivatives’ fair value are not included in current earnings but are included in OCI in stockholders’ equity. These changes in fair value will subsequently be reclassified into earnings, as applicable, when the forecasted transaction occurs. To the extent that a previously designated hedging transaction is no longer an effective hedge, any ineffectiveness measured in the hedging relationship is recorded currently in earnings in the period it occurs. The cash flows resulting from forward exchange contracts are classified in the consolidated statements of cash flows as part of cash flows from operating activities. The Company does not enter into derivative instruments for trading or speculative purposes. To the extent the hedge accounting criteria is not met, the related foreign currency forward contracts are considered as economic hedges and changes in the fair value of these contracts are recorded immediately in earnings in the period in which they occur. These include hedges that are used to reduce exchange rate risks arising from the change in fair value of certain foreign currency denominated assets and liabilities (i.e., payables, receivables) and other economic hedges where the hedge accounting criteria were not met. As of December 31, 2015 and 2014, the Company had outstanding forward foreign exchange contracts with gross notional values of $89,989 and $28,650, respectively. The following tables provide a summary of the primary net hedging positions and corresponding fair values held as of December 31, 2015 and 2014: December 31, 2015 Currency Hedged (Buy/Sell) Gross Notional Fair Value (1) U.S. Dollar/Japanese Yen $ 26,848 $ (136 ) U.S. Dollar/South Korean Won 34,777 915 U.S. Dollar/Euro 10,987 19 U.S. Dollar/U.K. Pound Sterling 4,587 61 U.S. Dollar/Taiwan Dollar 12,790 364 Total $ 89,989 $ 1,223 December 31, 2014 Currency Hedged (Buy/Sell) Gross Notional Fair Value (1) U.S. Dollar/Japanese Yen $ 8,035 $ 1,107 U.S. Dollar/South Korean Won 12,512 372 U.S. Dollar/Euro 2,060 185 U.S. Dollar/U.K. Pound Sterling 1,308 70 U.S. Dollar/Taiwan Dollar 4,735 232 Total $ 28,650 $ 1,966 (1) Represents the receivable (payable) amount included in the consolidated balance sheet. The following table provides a summary of the fair value amounts of the Company’s derivative instruments: Years Ended December 31, Derivatives Designated as Hedging Instruments 2015 2014 Derivative assets: Forward exchange contracts $ 1,486 $ 1,966 Derivative liabilities: Forward exchange contracts (263 ) — Total net derivative asset designated as hedging instruments (1) $ 1,223 $ 1,966 (1) The derivative asset of $1,486 and derivative liability of $(263) are classified in other current assets and other current liabilities in the consolidated balance sheet as of December 31, 2015. The derivative asset of $1,966 is classified in other current assets in the consolidated balance sheet as of December 31, 2014. These foreign exchange contracts are subject to a master netting agreement with one financial institution. However, the Company has elected to record these contracts on a gross basis in the balance sheet. The net amount of existing gains as of December 31, 2015 that is expected to be reclassified from OCI into earnings within the next twelve months is immaterial. The following table provides a summary of the (losses) gains on derivatives designated as hedging instruments: Years Ended December 31, Derivatives Designated as Cash Flow Hedging Instruments 2015 2014 2013 Forward exchange contracts: Net loss recognized in OCI (1) $ (3,748 ) $ (984 ) $ (48 ) Net gain (loss) reclassified from OCI into income (2) $ 3,520 $ (160 ) $ 1,086 (1) Net change in the fair value of the effective portion classified in OCI. (2) Effective portion classified as cost of products in 2015, 2014 and 2013. The following table provides a summary of the (losses) gains on derivatives not designated as hedging instruments: Years Ended December 31, Derivatives Not Designated as Hedging Instruments 2015 2014 2013 Forward exchange contracts: Net (loss) gain recognized in income (1) $ (40 ) $ 101 $ (215 ) (1) The Company enters into foreign exchange contracts to hedge against changes in the balance sheet, including accounts receivable and intercompany loans, for certain subsidiaries. These derivatives are not designated as hedging instruments.

Inventories

Inventories	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Inventories	8) Inventories Inventories consist of the following: Years Ended December 31, 2015 2014 Raw material $ 78,352 $ 81,121 Work-in-process 23,297 26,604 Finished goods 50,982 47,444 $ 152,631 $ 155,169 Inventory-related excess and obsolete charges of $13,602, $12,131 and $21,671 were recorded in cost of products for the years ended December 31, 2015, 2014 and 2013, respectively. Included in excess and obsolete charges for 2013 was $6,423 of special charges for obsolete inventory related to a unique product in a solar application as a result of slowing market conditions, which provided uncertainty as to the net realizable value of this inventory.

Property, Plant and Equipment

Property, Plant and Equipment	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	9) Property, Plant and Equipment Property, plant and equipment consist of the following: Years Ended December 31, 2015 2014 Land $ 8,535 $ 8,650 Buildings 68,881 66,885 Machinery and equipment 119,739 122,720 Furniture and fixtures, office equipment and software 61,490 59,972 Leasehold improvements 21,303 21,353 Construction in progress 4,171 3,647 284,119 283,227 Less: accumulated depreciation 215,263 210,451 $ 68,856 $ 72,776 Depreciation of property, plant and equipment totaled $15,339, $15,569 and $14,964 for the years ended 2015, 2014 and 2013, respectively.

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2015
Business Combinations [Abstract]
Acquisitions	10) Acquisitions Precisive, LLC On March 17, 2015, the Company acquired Precisive, LLC (“Precisive”) for $12,085, net of cash acquired of $435. The purchase price includes a deferred payment amount of $2,600 to cover any potential indemnification claims, which amount will be paid to the sellers after 15 months assuming there are no indemnification claims. Precisive is an innovative developer of optical analyzers based on Tunable Filter Spectroscopy, which provide real-time gas analysis in the natural gas and hydrocarbon processing industries, including refineries, hydrocarbon processing plants, gas-to-power machines, biogas processes and fuel gas transportation and metering, while delivering customers a lower total cost of ownership. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of acquisition: Current assets $ 693 Non-current assets 18 Intangible assets 5,110 Goodwill 7,042 Total assets acquired 12,863 Total current liabilities assumed (343 ) Fair value of assets acquired and liabilities assumed 12,520 Less cash acquired (435 ) Total purchase price, net of cash acquired $ 12,085 Substantially all of the purchase price was deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis, which approximates the pattern of use. Order backlog $ 50 18 months Customer relationships 1,430 8 years Exclusive patent license 2,600 10 years Trade names 210 10 years Developed technology 820 10 years $ 5,110 The fair value of the acquired intangibles was determined using the income approach. This acquisition resulted in a purchase price that exceeded the estimated fair value of tangible and intangible assets, the excess amount of which was allocated to goodwill. The Company believes the amount of goodwill relative to identifiable intangible assets relates to several factors including: (1) potential buyer-specific synergies related to market opportunities for a combined product offering; (2) potential to leverage the Company’s sales force and intellectual property to attract new customers and revenue; and (3) potential to strengthen and expand into new but complementary markets, including targeting new applications such as natural gas processing, hydrocarbon processing and other oil and gas segments. The results of this acquisition were included in the Company’s consolidated operations beginning on March 17, 2015. The pro forma consolidated statements reflecting the operating results of Precisive, had it been acquired January 1, 2014, would not differ materially from the operating results of the Company as reported for the year ended December 31, 2015. Precisive is included in the Company’s Instruments, Control and Vacuum Products group and the Advanced Manufacturing Capital Equipment reportable segment. Granville-Phillips On May 30, 2014, the Company acquired Granville-Phillips (“GP”), a division of Brooks Automation, Inc., for $86,950. GP is a leading global provider of vacuum measurement and control instruments to the semiconductor, thin film and general industrial markets. The Company believes that the amount of goodwill relative to identifiable intangible assets relates to several factors, including: a well-regarded leader in indirect vacuum gauges, a premium brand, an excellent reputation for quality, reliability and performance and an assembled workforce. The acquisition reflects the Company’s strategy to grow our semiconductor business, while diversifying into other high growth advanced markets. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of acquisition: Inventory $ 5,198 Property and equipment 299 Other assets 191 Intangible assets 38,850 Goodwill 42,587 Warranty liability (175 ) Total purchase price $ 86,950 Substantially all of the purchase price was deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles are being amortized on a straight-line basis. Customer relationships $ 21,250 7 years Trademark and trade names 1,900 12 years Developed technology 15,700 9-12 years $ 38,850 This transaction resulted in an amount of purchase price that exceeded the estimated fair value of tangible and intangible assets, which was allocated to goodwill. The Company believes that the amount of goodwill relative to identifiable intangible assets relates to several factors including: (1) potential buyer-specific synergies related to market opportunities for a combined product offering; (2) potential to leverage the Company’s sales force and intellectual property to attract new customers and revenue and (3) potential to strengthen the Company’s position in the vacuum gauge market. The results of this acquisition were included in the Company’s consolidated operations beginning on May 30, 2014. The pro forma consolidated statements reflecting the operating results of GP, had it been acquired as of January 1, 2013, would not differ materially from the operating results of the Company as reported for the year ended December 31, 2014. GP is included in the Company’s Instruments, Control and Vacuum Products group and the Advanced Manufacturing Capital Equipment reportable segment. Alter S.r.l On March 12, 2013, the Company acquired Alter S.r.l. (“Alter”), located in Reggio Emilia, Italy. The aggregate purchase price, net of cash acquired and after final debt and working capital adjustments was $2,426. Total cash paid as of June 30, 2013, net of cash acquired of $21 was $2,058. Alter develops advanced microwave power generators, components and systems for industrial microwave heating, microwave plasma coating and semiconductor applications. This acquisition strengthened the Company’s existing microwave plasma expertise and product portfolio, and extended its opportunity into high growth, non-plasma microwave applications for industrial processes, food and beverage manufacturing and other markets. The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of the acquisition: Current assets $ 1,053 Property and equipment 211 Intangible assets 2,806 Goodwill 381 Other assets 67 Total assets acquired 4,518 Debt (Note 15) 770 Deferred taxes and other liabilities 1,301 Total liabilities assumed 2,071 Total purchase price 2,447 Cash acquired (21 ) Total purchase price, net of cash acquired $ 2,426 The intangible assets associated with the acquisition are not deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis. Current developed technology $ 2,208 9 year useful life Trademarks and trade names 598 3 year useful life $ 2,806 The results of this acquisition were included in the Company’s consolidated operations beginning on March 12, 2013. The pro forma consolidated statements reflecting the operating results of Alter, had it been acquired as of January 1, 2012, would not differ materially from the operating results of the Company as reported for the year ended December 31, 2013. Alter is included in the Company’s Power and Reactive Gas Products group and the Advanced Manufacturing Capital Equipment reportable segment.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	11) Goodwill and Intangible Assets Goodwill The changes in the carrying amount of goodwill and accumulated impairment losses were as follows: 2015 2014 Gross Accumulated Net Gross Accumulated Net Beginning balance at January 1 $ 331,795 $ (139,414 ) $ 192,381 $ 290,323 $ (139,414 ) $ 150,909 Acquired goodwill(1) 8,017 — 8,017 41,993 — 41,993 Foreign currency translation (695 ) — (695 ) (521 ) — (521 ) Ending balance at December 31 $ 339,117 $ (139,414 ) $ 199,703 $ 331,795 $ (139,414 ) $ 192,381 (1) During 2015, the Company recorded $7,042 of goodwill related to the acquisition of Precisive. During the second quarter of 2015, the Company recorded a purchase accounting adjustment of $975 primarily related to an inventory valuation adjustment related to the acquisition of GP. During 2014, the Company recorded $41,612 of goodwill related to the acquisition of GP and recorded a purchase accounting adjustment of $381 related to the 2013 purchase of Alter S.r.l. Intangible Assets The Company is required to test certain long-lived assets when indicators of impairment are present. For the purposes of the impairment test, long-lived assets are grouped with other assets and liabilities at the lowest level for which identifiable cash flows are largely independent of the cash flows of other assets and liabilities. There were no intangible asset impairment charges in 2015, 2014 or 2013. Components of the Company’s acquired intangible assets are comprised of the following: As of December 31, 2015 Gross Accumulated Foreign Currency Net Completed technology(1) $ 101,200 $ (82,330 ) $ (272 ) $ 18,598 Customer relationships(1) 37,251 (16,345 ) 10 20,916 Patents, trademarks, trade names and other(1) 30,396 (25,888 ) 5 4,513 $ 168,847 $ (124,563 ) $ (257 ) $ 44,027 (1) During 2015, the Company recorded $5,110 of separately identified intangible assets related to the acquisition of Precisive, of which $820 was completed technology, $1,430 was customer relationships and $2,860 was patents, trademarks, trade names and other. As of December 31, 2014 Gross Accumulated Foreign Currency Net Completed technology(1) $ 100,380 $ (79,875 ) $ 135 $ 20,640 Customer relationships(1) 35,821 (12,634 ) 280 23,467 Patents, trademarks, trade names and other(1) 27,536 (25,290 ) 36 2,282 $ 163,737 $ (117,799 ) $ 451 $ 46,389 (1) During 2014, the Company recorded $38,850 of separately identified intangible assets related to the acquisition of GP, of which $15,700 was completed technology, $21,250 was customer relationships and $1,900 was patents, trademarks, trade names and other. Aggregate amortization expense related to acquired intangible assets for the years 2015, 2014 and 2013 was $6,764, $4,945 and $2,139, respectively. Aggregate amortization expense related to acquired intangible assets for future years is: Year Amount 2016 $ 6,644 2017 6,561 2018 6,546 2019 6,504 2020 6,450 Thereafter 11,322

Other Assets

Other Assets	12 Months Ended
	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Other Assets	12) Other Assets Years Ended December 31, 2015 2014 Other Current Assets: Income tax receivable $ 8,682 $ 10,322 Prepaid income tax 4,755 4,698 VAT tax receivable 3,264 3,417 Other 10,059 9,075 Total other current assets $ 26,760 $ 27,512 Other Assets: Deferred tax assets, net $ 19,252 $ 7,202 Long-term income tax receivable — 8,092 Other 1,998 1,912 Total other assets $ 21,250 $ 17,206

Other Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Other Liabilities	13) Other Liabilities Years Ended December 31, 2015 2014 Other Current Liabilities: Product warranties $ 5,205 $ 6,266 Deferred revenue 7,189 8,283 Other 22,965 21,240 Total other current liabilities $ 35,359 $ 35,789 Other Liabilities: Long-term income tax payable $ 4,483 $ 20,203 Accrued compensation 13,395 12,068 Other 3,604 6,324 Total other liabilities $ 21,482 $ 38,595

Product Warranties

Product Warranties	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Product Warranties	14) Product Warranties The Company provides for the estimated costs to fulfill customer warranty obligations upon the recognition of the related revenue. While the Company engages in extensive product quality programs and processes, including actively monitoring and evaluating the quality of its component suppliers, the Company’s warranty obligation is affected by shipment volume, product failure rates, utilization levels, material usage and supplier warranties on parts delivered to the Company. Should actual product failure rates, utilization levels, material usage, or supplier warranties on parts differ from the Company’s estimates, revisions to the estimated warranty liability would be required. The product warranty liability is included in other current liabilities in the consolidated balance sheets. Product warranty activities were as follows: Years Ended December 31, 2015 2014 Beginning balance $ 6,266 $ 6,956 Provisions for product warranties 4,343 2,713 Direct charges to warranty liability (5,296 ) (3,271 ) Foreign currency translation (108 ) (132 ) Ending balance $ 5,205 $ 6,266

Debt

Debt	12 Months Ended
	Dec. 31, 2015
Debt Disclosure [Abstract]
Debt	15) Debt Credit Agreements and Short-Term Borrowings The Company’s Japanese subsidiary has lines of credit and short-term borrowing arrangements with two financial institutions which generally expire and are renewed at three month intervals. The lines of credit provided for aggregate borrowings as of December 31, 2015 of up to an equivalent of $19,082 U.S. dollars. One of the borrowing arrangements has an interest rate based on the Tokyo Interbank Offer Rate at the time of borrowing and the other has an interest rate based on the Japanese Short-term Prime Lending Rate. There were no borrowings outstanding under these arrangements at December 31, 2015 and 2014.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	16) Income Taxes A reconciliation of the Company’s effective tax rate to the U.S. federal statutory rate is as follows: Years Ended December 31, 2015 2014 2013 U.S. Federal income tax statutory rate 35.0 % 35.0 % 35.0 % Federal tax credits (1.2 ) (1.0 ) (1.8 ) State income taxes, net of federal benefit 1.3 2.0 1.3 Effect of foreign operations taxed at various rates (6.4 ) (7.3 ) 0.3 Qualified production activity tax benefit (1.6 ) (1.8 ) (1.4 ) Deferred tax asset valuation allowance — (0.5 ) (0.7 ) Release of income tax reserves (including interest) (4.8 ) (10.7 ) — Foreign dividends, net of foreign tax credits 0.7 (1.0 ) — Income tax charges on accumulated foreign earnings — — 10.9 Tax benefit related to reinstatement of tax incentives — — (4.0 ) Other 0.3 0.4 0.1 23.3 % 15.1 % 39.7 % The components of income from continuing operations before income taxes and the related provision for income taxes consist of the following: Years Ended December 31, 2015 2014 2013 Income from continuing operations before income taxes: United States $ 90,401 $ 86,015 $ 29,546 Foreign 69,067 50,378 29,755 $ 159,468 $ 136,393 $ 59,301 Current taxes: United States $ 15,813 $ 8,361 $ 11,338 State 2,927 1,124 1,159 Foreign 18,021 5,866 14,117 36,761 15,351 26,614 Deferred taxes: United States (862 ) 8,908 (1,730 ) State and Foreign 1,272 (3,644 ) (1,359 ) 410 5,264 (3,089 ) Provision for income taxes $ 37,171 $ 20,615 $ 23,525 The significant components of the deferred tax assets and deferred tax liabilities are as follows: Years Ended December 31, 2015 2014 Deferred tax assets: Loss carry-forwards and credits $ 8,531 $ 30,523 Inventory and warranty reserves 15,404 15,015 Accounts receivable and other accruals 2,343 2,885 Stock-based compensation 3,713 3,255 Executive supplemental retirement benefits 3,947 3,321 Other — 283 Total deferred tax assets $ 33,938 $ 55,282 Deferred tax liabilities: Acquired intangible assets (9,434 ) (9,205 ) Depreciation and amortization (1,724 ) (2,609 ) Other (57 ) — Total deferred tax liabilities (11,215 ) (11,814 ) Valuation allowance (6,127 ) (26,763 ) Net deferred tax assets $ 16,596 $ 16,705 As of December 31, 2015, the Company had gross Massachusetts research and other tax credit carry-forwards of $8,933. These credit carry-forwards will expire at various dates through 2029. The Company also had gross net operating loss carry-forwards from various state and foreign jurisdictions of $7,784. Included in the total carry-forward are $5,000 of losses that can be carried forward indefinitely while the remaining losses of $2,784 begin to expire in 2021. Although the Company believes that its tax positions are consistent with applicable U.S. federal, state and international laws, it maintains certain tax reserves at December 31, 2015 in the event its tax positions were to be challenged by the applicable tax authority and additional tax assessed on audit. A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows: Years Ended December 31, 2015 2014 2013 Balance at beginning of year $ 19,610 $ 47,684 $ 40,674 Decreases for prior years (26 ) (13 ) — Increases for the current year 322 550 7,308 Reductions related to settlements with taxing authorities (15,370 ) (18,235 ) — Reductions related to expiration of statute of limitations (204 ) (10,376 ) (298 ) Balance at end of year $ 4,332 $ 19,610 $ 47,684 As of December 31, 2015, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $4,332. As of December 31, 2014, the total amount of gross unrecognized tax benefits, which excludes interest and penalties, was $19,610. The net decrease from December 31, 2014 was primarily attributable to current year releases in reserves for existing uncertain tax positions. At December 31, 2015, excluding interest and penalties, there are $4,326 of net unrecognized tax benefits that, if recognized, would impact the Company’s annual effective tax rate. In 2015, the Company recorded a net benefit to income tax expense of $7,304, excluding interest and penalties, due to the release of income tax reserves related to the effective settlement of a U.S. income tax audit. The Company accrues interest and, if applicable, penalties for any uncertain tax positions. Interest and penalties are classified as a component of income tax expense. At December 31, 2015, 2014 and 2013, the Company had accrued interest on unrecognized tax benefits of approximately $157, $578 and $2,159, respectively. Over the next 12 months it is reasonably possible that the Company may recognize approximately $923 of previously net unrecognized tax benefits, excluding interest and penalties, related to state and foreign tax positions as a result of the expiration of statutes of limitation. The Company is subject to examination by U.S. federal, state and foreign tax authorities. The United States Internal Revenue Service commenced an examination of our U.S. federal tax filings for tax years 2011 through 2013 during the quarter ended March 31, 2015. This audit was effectively settled in the fourth quarter upon the Company’s acceptance of the income tax examination changes. As part of the audit, the Company consented to extend the U.S. statute of limitations for tax year 2011 until September 30, 2016. The Company also effectively settled another U.S. federal income tax examination, for tax years 2007 through 2009, during the fourth quarter of 2014 upon receipt of an audit approval letter from the Joint Committee on Taxation. The statute of limitations for tax years 2007 through 2009 expired on December 31, 2015. The U.S. statute of limitations remains open for tax years 2011 through present. The statute of limitations for tax filings in other jurisdictions varies between fiscal years 2008 through present. On a quarterly basis, the Company evaluates both positive and negative evidence that affects the realizability of net deferred tax assets and assesses the need for a valuation allowance. The future benefit to be derived from its deferred tax assets is dependent upon its ability to generate sufficient future taxable income to realize the assets. During 2015, the Company decreased its valuation allowance by $20,636, primarily related the expiration of U.S. capital loss carry-forwards. During 2014, the Company decreased its valuation allowance by $339, primarily related to the effective settlement of a foreign tax audit. During 2013, the Company decreased its valuation allowance by $395, primarily related to the expiration of U.S. capital loss carry-forwards. Through December 31, 2015, the Company has not provided deferred income taxes on the undistributed earnings of its foreign subsidiaries because such earnings are intended to be permanently reinvested outside of the United States. Determination of the potential deferred income tax liability on these undistributed earnings is not practicable because such liability, if any, is dependent on circumstances existing and tax planning choices available when remittance occurs. At December 31, 2015, the Company had approximately $450,000 of undistributed earnings in its foreign subsidiaries which are considered to be indefinitely reinvested. The Company’s Israeli subsidiary elected to be treated under a preferential Israeli tax regime under which a reduced tax rate of 7% applied for 2013, increased to 9% for 2014, and remained 9% for 2015 for a portion of its taxable income. The Company’s other operations in Israel are also taxed at a preferential rate under the tax regime at 16%. The Company’s Israeli subsidiary effectively settled an examination for tax years 2009 through 2011 during the quarter ended March 31, 2014.

Stockholders' Equity

Stockholders' Equity	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Stockholders' Equity	17) Stockholders’ Equity Stock Repurchase On July 25, 2011, the Company’s board of directors approved a share repurchase program for the repurchase of up to an aggregate of $200,000 of its outstanding common stock from time to time in open market purchases, privately negotiated transactions or through other appropriate means. The timing and quantity of any shares repurchased will depend upon a variety of factors, including business conditions, stock market conditions and business development activities, including, but not limited to, merger and acquisition opportunities. These repurchases may be commenced, suspended or discontinued at any time without prior notice. During 2015, the Company repurchased 369,133 shares of its common stock for $13,294 at an average price of $36.01 per share. During 2014, the Company repurchased 727,912 shares of its common stock for $20,809 at an average price of $28.59 per share. Dividends Holders of the Company’s common stock are entitled to receive dividends when and if they are declared by the Company’s board of directors. During 2015, the Company’s board of directors declared a cash dividend of $0.165 per share during the first quarter of 2015 and a cash dividend of $0.17 per share during the second, third and fourth quarters of 2015, which totaled $35,969. During 2014, the Company’s board of directors declared a cash dividend of $0.16 per share during the first quarter of 2014 and a cash dividend of $0.165 per share during the second, third and fourth quarters of 2014, which totaled $34,851. Future dividend declarations, if any, as well as the record and payment dates for such dividends, are subject to the final determination of the Company’s board of directors. On February 8, 2016, the Company’s board of directors declared a quarterly cash dividend of $0.17 per share to be paid on March 11, 2016 to shareholders of record as of February 29, 2016.

Stock-Based Compensation

Stock-Based Compensation	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	18) Stock-Based Compensation Employee Stock Purchase Plans The Company’s Fourth Restated 1999 Employee Stock Purchase Plan (the “Purchase Plan”) authorized the issuance of up to an aggregate of 1,950,000 shares of common stock to participating employees. Offerings under the Purchase Plan commenced on June 1 and December 1 and terminated, respectively, on November 30 and May 31. Under the Purchase Plan, eligible employees purchased shares of common stock through payroll deductions of up to 10% of their compensation or up to an annual maximum amount of $21,250. The price at which an employee’s purchase option was exercised was the lower of (1) 85% of the closing price of the common stock on the NASDAQ Global Select Market on the day that each offering commenced, or (2) 85% of the closing price on the day that each offering terminated. During 2014, the Company issued 69,474 shares of common stock to employees who participated in the Purchase Plan at an exercise price of $24.52 per share. As of June 1, 2014, the Purchase Plan was replaced by the 2014 Employee Stock Purchase Plan (the “2014 ESPP Plan”). The Company’s Third Amended and Restated International Employee Stock Purchase Plan (the “Foreign Purchase Plan”) authorized the issuance of up to an aggregate of 400,000 shares of common stock to participating employees. Offerings under the Foreign Purchase Plan commenced on June 1 and December 1 and terminated, respectively, on November 30 and May 31. Under the Foreign Purchase Plan, eligible employees purchased shares of common stock through payroll deductions of up to 10% of their compensation or up to an annual maximum amount of $21,250. The price at which an employee’s purchase option was exercised was the lower of (1) 85% of the closing price of the common stock on the NASDAQ Global Select Market on the day that each offering commenced, or (2) 85% of the closing price on the day that each offering terminated. During 2014, the Company issued 20,053 shares of common stock to employees who participated in the Foreign Purchase Plan at an exercise price of $24.52 per share. As of June 1, 2014, the Foreign Purchase Plan was replaced by the 2014 ESPP Plan. The 2014 ESPP Plan was adopted by the Board of Directors on February 10, 2014 and approved by the Company’s stockholders on May 5, 2014. The 2014 ESPP Plan authorizes the issuance of up to an aggregate of 2,500,000 shares of common stock to participating employees. Offerings under the 2014 ESPP Plan commence on June 1 and December 1 and terminate, respectively, on November 30 and May 31. Under the 2014 ESPP Plan, eligible employees may purchase shares of common stock through payroll deductions of up to 10% of their compensation or up to an annual maximum amount of $21,250. The price at which an employee’s purchase option is exercised is the lower of (1) 85% of the closing price of the common stock on the NASDAQ Global Select Market on the day that each offering commences, or (2) 85% of the closing price on the day that each offering terminates. During 2015 and 2014, the Company issued 140,531 and 82,481 shares, respectively, of common stock to employees who participated in the 2014 ESPP Plan at exercise prices of $30.74 and $31.34 per share in 2015 and $24.33 per share in 2014. As of December 31, 2015, there were 2,276,988 shares reserved for future issuance under the 2014 ESPP Plan. Equity Incentive Plans The Company has granted options to employees under the 2004 Stock Incentive Plan (the “2004 Plan”) and the Second Restated 1995 Stock Incentive Plan (the “1995 Plan”), and to directors under the 1997 Director Stock Plan (the “1997 Director Plan”); the Company has also granted restricted stock units (“RSUs”) to employees and directors under the 2004 Plan and the 2014 Stock Incentive Plan (the “2014 Plan” and together with the 2004 Plan, the 1995 Plan, and the 1997 Director Plan, the “Plans”). The Plans are administered by the Compensation Committee of the Company’s Board of Directors. The Plans are intended to attract and retain employees and to provide an incentive for them to assist the Company to achieve long-range performance goals and to enable them to participate in the long-term growth of the Company. Employees may be granted RSUs, options to purchase shares of the Company’s stock and other equity incentives under the Plans. The Company’s 2014 Plan was adopted by the Board of Directors on February 10, 2014 and approved by the Company’s stockholders on May 5, 2014. Up to 18,000,000 shares of common stock (subject to adjustment in the event of stock splits and other similar events) may be issued pursuant to awards granted under the 2014 Plan. The Company may grant options, RSUs, restricted stock appreciation rights and other stock-based awards to employees, officers, directors, consultants and advisors under the 2014 Plan. Any full-value awards granted under the 2014 Plan will be counted against the shares reserved for issuance under the 2014 Plan as 2.4 shares for each share of common stock subject to such award and any award granted under the 2014 Plan that is not a full-value award (including, without limitation, any option or SAR) will be counted against the shares reserved for issuance under the plan as one share for each one share of common stock subject to such award. “Full-value award” means any RSU, or other stock-based award with a per share price or per unit purchase price lower than 100% of fair market value on the date of grant. To the extent a share that was subject to an award that counted as one share is returned to the 2014 Plan, each applicable share reserve will be credited with one share. To the extent that a share that was subject to an award that counts as 2.4 shares is returned to the 2014 Plan, each applicable share reserve will be credited with 2.4 shares. As of December 31, 2015, there were 16,953,488 shares reserved for future issuance under the 2014 Plan. The Company’s 2004 Plan expired in March 2014 and no further awards may be granted under the 2004 Plan, although there are still outstanding RSUs which may vest under the 2004 Plan. The Company’s 1995 Plan expired in November 2005 and no further awards may be granted under the 1995 Plan. The Company’s 1997 Director Plan expired in February 2007 and no further awards may be granted under the 1997 Director Plan. Stock options were granted at an exercise price equal to 100% of the fair value of the Company’s common stock on the date of grant. Generally, stock options granted to employees under the 1995 Plan and the 2004 Plan from 2001 to 2006, vested 25% after one year and 6.25% per quarter thereafter, and expired 10 years after the grant date. Options granted to directors generally vested at the earliest of (1) one day prior to the next annual meeting, (2) 13 months from the date of grant, or (3) the effective date of an acquisition. There were no remaining outstanding stock options as of December 31, 2015 under any of the Plans. RSUs granted to employees in 2015, 2014 and 2013 generally vest 33.3% per year on the anniversary of the date of grant. RSUs granted to employees who are at least 60 years old and have a minimum of 10 Years of Service (as defined in the applicable RSU agreement) are expensed immediately. RSUs granted to directors generally vest at the earliest of (1) one day prior to the next annual meeting, (2) 13 months from date of grant, or (3) the effective date of an acquisition. Certain RSUs are subject to performance conditions (“performance shares”) under the Company’s 2004 Plan and 2014 Plan. Such performance shares are available, subject to time-based vesting conditions, if, and to the extent that, financial or operational performance criteria for the applicable period are achieved. Accordingly, the number of performance shares earned will vary based on the level of achievement of financial or operational performance objectives for the applicable period. The following table presents the activity for RSUs under the Plans: Year Ended December 31, 2015 Non-vested RSUs Weighted Non-vested RSUs — beginning of period 716,714 $ 28.67 Granted 394,952 $ 32.89 Vested (351,601 ) $ 28.59 Forfeited or expired (26,903 ) $ 29.84 Non-vested RSUs — end of period 733,162 $ 30.94 The following table presents the activity for options under the Plans: Year Ended December 31, 2015 Options Weighted Outstanding — beginning of period 30,224 $ 19.67 Exercised (30,100 ) $ 19.68 Forfeited or expired (124 ) $ 18.16 Outstanding — end of period — $ — Exercisable at end of period — $ — There were no options outstanding or exercisable under the Plans at December 31, 2015. The total cash received from employees as a result of employee stock option exercises during the years 2015 and 2014 was approximately $592 and $1,605, respectively. In connection with these exercises, the tax benefit realized by the Company for the years 2015 and 2014 was approximately $21 and $175, respectively. The Company settles employee stock option exercises and restricted stock unit vesting with newly issued common shares. Stock-Based Compensation Expense The Company recognized the full impact of its share-based payment plans in the consolidated statements of operations and comprehensive income for the years 2015, 2014 and 2013. As of December 31, 2015 and 2014, the Company capitalized $471 of such cost on its consolidated balance sheet. The following table reflects the effect of recording stock-based compensation for the years 2015, 2014 and 2013: Years Ended December 31, Stock-based compensation expense by type of award: 2015 2014 2013 Restricted stock units $ 11,885 $ 10,203 $ 12,982 Employee stock purchase plan 1,128 1,112 1,010 Total stock-based compensation 13,013 11,315 13,992 Tax effect on stock-based compensation (836 ) (331 ) (495 ) Net effect on net income $ 12,177 $ 10,984 $ 13,497 Effect on net earnings per share: Basic $ 0.23 $ 0.21 $ 0.25 Diluted $ 0.23 $ 0.21 $ 0.25 The pre-tax effect within the consolidated statements of operations and comprehensive income of recording stock-based compensation for the years 2015, 2014 and 2013 was as follows: Years Ended December 31, 2015 2014 2013 Cost of revenues $ 1,814 $ 1,960 $ 2,038 Research and development expense 1,590 1,659 1,902 Selling, general and administrative expense 9,609 7,696 10,052 Total pre-tax stock-based compensation expense $ 13,013 $ 11,315 $ 13,992 Valuation Assumptions The Company determines the fair value of restricted stock units based on the closing market price of the Company’s common stock on the date of the award, and estimates the fair value of stock options and employee stock purchase plan rights using the Black-Scholes valuation model. Such values are recognized as expense on a straight-line basis over the requisite service periods, net of estimated forfeitures except for retirement eligible employees in which the Company expenses the fair value of the grant in the period the grant is issued. The estimation of stock-based awards that will ultimately vest requires significant judgment. The Company considers many factors when estimating expected forfeitures, including types of awards and historical experience. Actual results, and future changes in estimates, may differ substantially from the Company’s current estimates. The Company did not grant options during 2015, 2014 and 2013. The total intrinsic value of options exercised during 2015, 2014 and 2013 was approximately $494, $958 and $684, respectively. The weighted average fair value per share of employee stock purchase plan rights granted in 2015, 2014 and 2013 was $8.16, $6.37 and $5.76, respectively. The fair value of the employees’ purchase plan rights was estimated using the Black-Scholes option-pricing model with the following weighted average assumptions: Years Ended December 31, Employee stock purchase plan rights: 2015 2014 2013 Expected life (years) 0.5 0.5 0.5 Risk-free interest rate 0.1 % 0.1 % 0.1 % Expected volatility 26.4 % 26.4 % 27.7 % Expected annual dividends per share $ 0.675 $ 0.655 $ 0.64 Expected volatilities for 2015, 2014 and 2013 are based on a combination of implied and historical volatilities of the Company’s common stock; the expected life represents the weighted average period of time that options granted are expected to be outstanding giving consideration to vesting schedules and the Company’s historical exercise patterns; and the risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant for periods corresponding with the expected life of the option. The total intrinsic value of options exercised and the total fair value of RSUs vested during 2015, 2014 and 2013 was approximately $12,868, $12,106 and $19,221, respectively. As of December 31, 2015, the unrecognized compensation cost related to restricted stock units was approximately $11,585 and will be recognized over an estimated weighted average amortization period of 0.82 years.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2015
Postemployment Benefits [Abstract]
Employee Benefit Plans	19) Employee Benefit Plans The Company has a 401(k) profit-sharing plan for U.S. employees meeting certain requirements in which eligible employees may contribute between 1% and 50% of their annual compensation to this plan, and, with respect to employees who are age 50 and older, certain specified additional amounts, limited by an annual maximum amount determined by the Internal Revenue Service. The Company, at its discretion, may provide a matching contribution of 50% of each participant’s contributions up to 6% of eligible salary. At the discretion of the board of directors, the Company may also make additional contributions for the benefit of all eligible employees. The Company’s contributions were $2,667, $2,484 and $2,334 for 2015, 2014 and 2013, respectively. The Company has one foreign defined benefit plan which is frozen for Company contributions. The total accrual and projected benefit obligation is not material for this plan. The Company maintains a bonus plan which provides cash awards to key employees, at the discretion of the compensation committee of the board of directors, based upon operating results and employee performance. In addition, the Company’s foreign locations also have various bonus plans based upon local operating results and employee performance. The total bonus expense was $14,599, $14,434 and $16,006 for 2015, 2014 and 2013, respectively. The Company provides supplemental retirement benefits for one of its current executive officers and a number of former retired executives. The total cost of these benefits was $1,704, $2,258 and $4,988 for 2015, 2014 and 2013, respectively. The accumulated benefit obligation was $10,645 and $8,941 at December 31, 2015 and 2014, respectively, which was included in other long-term liabilities.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Net Income Per Share	20) Net Income Per Share Basic earnings per share (“EPS”), is computed by dividing income available to common stockholders by the weighted-average number of common shares outstanding during the period. The computation of diluted EPS is similar to the computation of basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding (using the treasury stock method), if securities containing potentially dilutive common shares (stock options and restricted stock units) had been converted to such common shares, and if such assumed conversion is dilutive. The following is a reconciliation of basic to diluted net income per share: Years Ended December 31, Numerator: 2015 2014 2013 Net income $ 122,297 $ 115,778 $ 35,776 Denominator: Shares used in net income per common share — basic 53,282,000 53,232,000 53,061,000 Effect of dilutive securities: Stock options, restricted stock and employee stock purchase plan 278,000 283,000 420,000 Shares used in net income per common share — diluted 53,560,000 53,515,000 53,481,000 Net income per common share: Basic $ 2.30 $ 2.17 $ 0.67 Diluted $ 2.28 $ 2.16 $ 0.67 As of December 31, 2015, restricted stock units relating to an aggregate of approximately 733,000 shares were outstanding. There were no stock options outstanding as of December 31, 2015. As of December 31, 2014 and 2013, stock options and restricted stock units relating to an aggregate of approximately 747,000 and 868,000 shares, respectively, were outstanding. In 2015, 2014 and 2013, the potential dilutive effect of 0, 600 and 83,000 weighted average shares, respectively, of stock options were excluded from the computation of diluted weighted-average shares outstanding as the shares would have an anti-dilutive effect on EPS.

Business Segment, Geographic Ar

Business Segment, Geographic Area, Product and Significant Customer Information	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Business Segment, Geographic Area, Product and Significant Customer Information	21) Business Segment, Geographic Area, Product and Significant Customer Information The Company develops, manufactures, sells and services products that measure, control, power, monitor and analyze critical parameters of advanced manufacturing processes. The Company’s Chief Operating Decision Maker (“CODM”) utilizes consolidated financial information to make decisions about allocating resources and assessing performance for the entire Company. In addition, certain disaggregated financial information is also provided to the CODM, which is used in the decision making process to assess performance. Based upon the information provided to the CODM, the Company has determined it has four reportable segments. Effective January 1, 2015, the Company changed the structure of its reportable segments based upon a change in the information that is provided to the Company’s CODM. The Company’s four reportable segments prior to the change in structure were: Advanced Manufacturing Capital Equipment, Analytical Solutions Group, Europe Region Sales & Service and Asia Region Sales & Service. The Company’s current structure still reflects four reportable segments, however, the composition of the segments has changed. The Company’s current reportable segments are Advanced Manufacturing Capital Equipment, Global Service, Asia Region Sales and Other. The primary change to the segment structure was to separate worldwide service from product sales and create a separate reportable segment known as Global Service. Product sales in the Advanced Manufacturing Capital Equipment segment remained with that segment. Asia product sales became a separate reportable segment. The product sales from the operating segments that made up the Analytical Solutions Group and Europe Region were included in the Other segment and are not reported separately as they are individually immaterial and collectively below the separate segment reporting guidelines. The Company has reported corporate expenses and certain intercompany pricing transactions in a Corporate and Eliminations reconciling column. Due to these changes, the results presented under segment reporting for the twelve months ended December 31, 2014 and 2013 reflect the current segments to conform to the current period segment reporting presentation with no impact to the consolidated results of operations. The Advanced Manufacturing Capital Equipment segment includes the development, manufacturing and sales of instruments, control and vacuum products, power and reactive gas products, all of which are utilized in semiconductor processing and other similar advanced manufacturing processes. Sales in this segment include both external sales and intercompany product sales, which are recorded at transfer prices in accordance with applicable tax requirements. The Global Service segment includes the worldwide servicing of instruments, control and vacuum products, power and reactive gas products, and certain other product groups, all of which are utilized in semiconductor processing and other similar advanced manufacturing processes. The Asia Region Sales segment mainly resells products from the Advanced Manufacturing Capital Equipment and Other segments into Asia regions. The Other segment includes operating segments that are not required to be reported separately as a reportable segment and includes sales of products that are re-sold from the Advanced Manufacturing Capital Equipment into Europe regions as well as sales from other operating segments. MKS derives the segment results directly from the manner in which results are reported in its management reporting system. The accounting policies MKS uses to derive reportable segment results are substantially the same as those used for external reporting purposes except that a substantial portion of the sales of the Advanced Manufacturing Capital Equipment and Other segments are intercompany sales to the regions at tax-based transfer prices and certain significant costs, including stock-based compensation and management incentive compensation, are not allocated to the segments and are included in Corporate and Eliminations. The CODM reviews several metrics of each operating segment, including net revenues and gross profit (loss). The Company does not maintain balance sheets for the majority of its operating segments and, as such, amounts have not been allocated to the reportable segments. The Company does not disclose external or intersegment revenues separately by reportable segment as this information is not presented to the CODM for decision making purposes. The following is net revenues by reportable segment: Years Ended December 31, 2015 2014 2013 Advanced Manufacturing Capital Equipment $ 662,911 $ 620,303 $ 509,008 Global Service 116,420 107,050 101,103 Asia Region Sales(1) 203,231 183,056 159,781 Other 79,523 82,709 73,235 Corporate, Eliminations (248,561 ) (212,249 ) (173,707 ) $ 813,524 $ 780,869 $ 669,420 The following is a reconciliation of segment gross profit to consolidated net income: Years Ended December 31, 2015 2014 2013 Gross profit by reportable segment: Advanced Manufacturing Capital Equipment $ 286,149 $ 254,292 $ 185,105 Global Service 39,532 38,147 35,721 Asia Region Sales(1) 27,494 27,184 26,874 Other 23,869 27,896 25,894 Corporate and Eliminations (14,172 ) (9,753 ) (7,020 ) Total gross profit by reportable segment 362,872 337,766 266,574 Operating expenses: Research and development 68,305 62,888 63,570 Selling, general and administrative 129,087 131,828 142,014 Insurance reimbursement — — (1,071 ) Acquisition costs 30 499 171 Restructuring 2,074 2,464 1,364 Amortization of intangible assets 6,764 4,945 2,139 Income from operations 156,612 135,142 58,387 Net interest income 2,856 1,251 914 Income before income taxes 159,468 136,393 59,301 Provision for income taxes 37,171 20,615 23,525 Net income $ 122,297 $ 115,778 $ 35,776 (1) The Asia Region Sales segment does not represent total geographical Asia financial information. This sales operation only represents the sales from the resale of Advanced Manufacturing Capital Equipment and Other segment products in its respective region. The Advanced Manufacturing Capital Equipment and Other segments both have sales in this region as well. Accordingly, total geographical sales include sales from multiple reportable segments. The following is capital expenditures by reportable segment for the years ended December 31, 2015, 2014 and 2013: Advanced Global Asia Region Sales Other Corporate and Total December 31, 2015: Capital expenditures $ 7,958 $ 839 $ 451 $ 526 $ 2,640 $ 12,414 December 31, 2014: Capital expenditures $ 8,081 $ 1,032 $ 525 $ 1,632 $ 1,913 $ 13,183 December 31, 2013: Capital expenditures $ 8,139 $ 955 $ 628 $ 627 $ 2,061 $ 12,410 The following is depreciation and amortization expense by reportable segment for the years ended December 31, 2015, 2014 and 2013: Advanced Global Asia Region Sales Other Corporate and Total December 31, 2015: Depreciation and amortization $ 17,009 $ 1,005 $ 353 $ 1,114 $ 2,622 $ 22,103 December 31, 2014: Depreciation and amortization $ 15,171 $ 1,097 $ 477 $ 1,204 $ 2,565 $ 20,514 December 31, 2013: Depreciation and amortization $ 11,848 $ 1,103 $ 398 $ 1,265 $ 2,488 $ 17,102 Total income tax expense is impracticable to present by reportable segment because the necessary information is not available or used by the CODM. Information about the Company’s operations in different geographic regions is presented in the tables below. Net revenues to unaffiliated customers are based on the location in which the sale originated. Transfers between geographic areas are at negotiated transfer prices and have been eliminated from consolidated net revenues. Years Ended December 31, Net revenues: 2015 2014 2013 United States $ 458,313 $ 448,452 $ 363,948 Korea 106,909 97,323 75,401 Japan 62,879 61,092 56,978 Europe 79,927 80,659 77,910 Asia (excluding Korea and Japan) 105,496 93,343 95,183 $ 813,524 $ 780,869 $ 669,420 Years Ended December 31, Long-lived assets:(1) 2015 2014 United States $ 56,594 $ 57,701 Europe 5,783 6,099 Asia 8,952 10,887 $ 71,329 $ 74,687 (1) Long-lived assets include property, plant and equipment, net and certain other assets, excluding long-term tax-related accounts. Goodwill associated with each of our reportable segments is as follows: December 31, 2015 December 31, 2014 Reportable segment: Advanced Manufacturing Capital Equipment $ 174,344 $ 166,946 Global Service 19,826 19,728 Asia Region Sales — — Other 6,228 6,228 Foreign currency translation (695 ) (521 ) Total goodwill $ 199,703 $ 192,381 Worldwide Product Information Because the reportable segment information above does not reflect worldwide sales of the Company’s products, the Company groups its products into three groups of similar products based upon the similarity of product function. Worldwide net revenue for each group of products is as follows: Years Ended December 31, 2015 2014 2013 Instruments, Control and Vacuum Products $ 402,345 $ 383,863 $ 341,375 Power and Reactive Gas Products 350,469 335,271 273,357 Analytical Solutions Products 60,710 61,735 54,688 $ 813,524 $ 780,869 $ 669,420 Sales of Instruments, Control and Vacuum Products and Power and Reactive Gas Products are included in the Company’s Advanced Manufacturing Capital Equipment, Asia Region Sales, Global Service and Other segments because the products are sold through these segments. Sales of the Analytical Solutions Products are included in the Asia Region Sales, Global Service and Other segments because the products are sold through these segments. Major Customers The Company had two customers with net revenues greater than 10% of total net revenues in the periods shown as follows: Years Ended December 31, 2015 2014 2013 Applied Materials, Inc. 17.8 % 19.1 % 17.0 % Lam Research Corporation 13.4 % 12.9 % 12.3 % Net revenues for each of our reportable segments include revenues from each of the two customers, which represent net revenues greater than 10% of total net revenues.

Restructurings

Restructurings	12 Months Ended
	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Restructurings	22) Restructurings During 2015, the Company recorded restructuring charges of $2,074. The restructuring charges were primarily for severance associated with the reduction in workforce of approximately 266 people throughout the Company as a result of the outsourcing of an international manufacturing operation and the consolidation of certain other foreign manufacturing locations. These restructuring charges primarily impacted our Advanced Manufacturing Capital Equipment and Other segments and was substantially complete at December 31, 2015. The activity related to the Company’s restructuring accrual is shown below: 2015 2014 Balance at January 1 $ 92 $ — Charged to expense 2,074 2,464 Payments (1,359 ) (2,372 ) Balance at December 31 $ 807 $ 92 During 2014, the Company recorded restructuring charges of $2,464. The restructuring charges were primarily for severance associated with the reduction in workforce of approximately 131 people throughout the Company. These restructuring charges impacted each of our reportable segments. This restructuring was substantially complete at December 31, 2014. During the first quarter of 2014, the Company re-classified certain assets from property, plant and equipment to current assets classified as held for sale, as these assets met the criteria for classification as held for sale. These assets relate to the Company closing one of its facilities in Colorado, as part of restructuring activities announced during the third quarter of 2013. The Company sold this building during the third quarter of 2014 for $1,316, net of commissions, and recorded an immaterial loss. During 2013, the Company initiated restructuring plans to consolidate a sales office and an engineering facility into other MKS facilities. The plans included a reduction in headcount. The Company recorded restructuring charges of $1,364 during 2013. The restructuring charges were primarily for severance and other charges associated with the reductions in workforce. The restructuring was substantially complete at December 31, 2013.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	23) Commitments and Contingencies The Company is subject to various legal proceedings and claims, which have arisen in the ordinary course of business. In the opinion of management, the ultimate disposition of these matters will not have a material adverse effect on the Company’s results of operations, financial condition or cash flows. The Company leases certain of its facilities and machinery and equipment under operating leases expiring in various years through 2022. Generally, the facility leases require the Company to pay maintenance, insurance and real estate taxes. Rental expense under operating leases totaled $7,845, $6,909 and $7,896 for 2015, 2014 and 2013, respectively. Minimum lease payments under operating leases are as follows: Year ending December 31, Operating Leases 2016 $ 7,315 2017 6,659 2018 5,127 2019 3,749 2020 2,513 Thereafter 2,266 Total minimum lease payments $ 27,629 As of December 31, 2015, the Company has entered into purchase commitments for certain inventory components and other equipment and services used in its normal operations. The majority of these purchase commitments covered by these arrangements are for periods of less than one year and aggregate to approximately $121,820. To the extent permitted by Massachusetts law, the Company’s Restated Articles of Organization, as amended, require the Company to indemnify any of its current or former officers or directors or any person who has served or is serving in any capacity with respect to any of the Company’s employee benefit plans. The Company believes that the estimated exposure for these indemnification obligations is currently not material. Accordingly, the Company has no material liabilities recorded for these requirements as of December 31, 2015. The Company also enters into agreements in the ordinary course of business which include indemnification provisions. Pursuant to these agreements, the Company indemnifies, holds harmless and agrees to reimburse the indemnified party, generally its customers, for losses suffered or incurred by the indemnified party in connection with certain patent or other intellectual property infringement claims, and, in some instances, other claims, by any third party with respect to the Company’s As part of past acquisitions and divestitures of businesses or assets, the Company has provided a variety of indemnifications to the sellers and purchasers for certain events or occurrences that took place prior to the date of the acquisition or divestiture. Typically, certain of the indemnifications expire after a defined period of time following the transaction, but certain indemnifications may survive indefinitely. The maximum potential amount of future payments the Company could be required to make for such obligations is undeterminable at this time. Other than obligations recorded as liabilities at the time of the acquisitions, historically the Company has not made significant payments for these indemnifications. Accordingly, no material liabilities have been recorded for these obligations. In conjunction with certain asset sales, the Company may provide routine indemnifications whose terms range in duration and often are not explicitly defined. Where appropriate, an obligation for such indemnification is recorded as a liability. Because the amounts of liability under these types of indemnifications are not explicitly stated, the overall maximum amount of the obligation under such indemnifications cannot be reasonably estimated. Other than obligations recorded as liabilities at the time of the asset sale, historically the Company has not made significant payments for these indemnifications.

Subsequent Event - Announcement

Subsequent Event - Announcement of the Acquisition of Newport Corporation	12 Months Ended
	Dec. 31, 2015
Subsequent Events [Abstract]
Subsequent Event - Announcement of the Acquisition of Newport Corporation	24) Subsequent Event - Announcement of the Acquisition of Newport Corporation On February 23, 2016, the Company announced that it had signed a definitive merger agreement to acquire Newport Corporation (“Newport”), a worldwide leader in photonics solutions. Pursuant to the merger agreement, the Company agreed to pay $23.00 per share in cash for all of the outstanding shares of Newport, for total cash consideration of approximately $980,000. The Company intends to fund the transaction with a combination of available cash on hand and up to $800,000 in committed debt financing. In addition, the Company entered into a commitment letter to obtain a $50,000 asset-based revolving credit facility for working capital purposes, as needed. The acquisition is expected to close in the second quarter of 2016, subject to customary closing conditions.

Supplemental Financial Data

Supplemental Financial Data	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Supplemental Financial Data	MKS Instruments, Inc. Supplemental Financial Data Quarter Ended March 31 June 30 Sept. 30, Dec. 31 (Table in thousands, except per share data) (Unaudited) 2015 Statement of Operations Data Net revenues $ 213,839 $ 217,966 $ 209,332 $ 172,387 Gross profit 97,046 98,798 94,229 72,799 Income from operations 47,010 46,034 41,363 22,205 Net income $ 33,786 $ 33,220 $ 29,769 $ 25,522 Net income per share: Basic $ 0.63 $ 0.62 $ 0.56 $ 0.48 Diluted $ 0.63 $ 0.62 $ 0.56 $ 0.48 Cash dividends paid per common share $ 0.165 $ 0.17 $ 0.17 $ 0.17 2014 Statement of Operations Data Net revenues $ 206,353 $ 184,697 $ 186,798 $ 203,021 Gross profit 89,372 79,635 79,325 89,434 Income from operations 37,778 30,660 28,150 38,554 Net income $ 31,245 $ 21,224 $ 29,117 $ 34,192 Net income per share: Basic $ 0.58 $ 0.40 $ 0.55 $ 0.64 Diluted $ 0.58 $ 0.40 $ 0.55 $ 0.64 Cash dividends paid per common share $ 0.16 $ 0.165 $ 0.165 $ 0.165

Schedule II - Valuation and Qua

Schedule II - Valuation and Qualifying Accounts	12 Months Ended
	Dec. 31, 2015
Valuation and Qualifying Accounts [Abstract]
Schedule II - Valuation and Qualifying Accounts	MKS INSTRUMENTS, INC. SCHEDULE II—VALUATION AND QUALIFYING ACCOUNTS Additions Description Balance at Charged to Charged to Deductions & Balance at (in thousands) Allowance for doubtful accounts: Years ended December 31, 2015 $ 2,250 $ (255 ) $ 21 $ (256 ) $ 1,760 2014 $ 1,924 $ 668 $ 12 $ (354 ) $ 2,250 2013 $ 2,078 $ 631 $ (62 ) $ (723 ) $ 1,924 Additions Description Balance at Charged to Charged to Other Deductions & Write-offs Balance at (in thousands) Allowance for sales returns: Years ended December 31, 2015 $ 730 $ 2,500 $ (3 ) $ (2,626 ) $ 601 2014 $ 827 $ 2,223 $ — $ (2,320 ) $ 730 2013 $ 801 $ 1,933 $ (36 ) $ (1,871 ) $ 827 Additions Description Balance at Charged to Charged to Deductions Balance at (in thousands) Valuation allowance on deferred tax asset: Years ended December 31, 2015 $ 26,763 $ — $ 113 $ (20,749 ) $ 6,127 2014 $ 27,102 $ — $ — $ (339 ) $ 26,763 2013 $ 27,497 $ — $ — $ (395 ) $ 27,102

Basis of Presentation (Policies

Basis of Presentation (Policies)	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”). The preparation of these financial statements requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and the disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. On an on-going basis, management evaluates its estimates and judgments, including those related to revenue recognition and allowance for doubtful accounts, inventory valuation, warranty costs, stock-based compensation, intangible assets, goodwill, other long-lived assets, in process research and development and other acquisition expenses and income taxes. Management bases its estimates and judgments on historical experience and on various other factors that are believed to be reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. Actual results may differ from these estimates under different assumptions or conditions.
Reclassifications	Reclassifications Certain prior year amounts have been reclassified to be consistent with current year classifications.
Revenue Recognition and Accounts Receivable Allowances	Revenue Recognition and Accounts Receivable Allowances Revenue from product sales is recorded upon transfer of title and risk of loss to the customer provided that there is evidence of an arrangement, the sales price is fixed or determinable, and collection of the related receivable is reasonably assured. In most transactions, the Company has no obligations to customers after the date products are shipped other than pursuant to warranty obligations. In some instances, the Company provides installation, training, support and services to customers after the product has been shipped. The Company does not frequently enter into arrangements with multiple deliverables; however, for those revenue arrangements with multiple deliverables, the Company allocates revenue to each element based upon its relative selling price using vendor-specific objective evidence (“VSOE”), or third-party evidence (“TPE”) or based upon the relative selling price using estimated prices if VSOE or TPE does not exist. The Company then recognizes revenue on each deliverable in accordance with its policies for product and service revenue recognition. The Company provides for the estimated costs to fulfill customer warranty obligations upon the recognition of the related revenue. Shipping and handling fees, if any, billed to customers are recognized as revenue. The related shipping and handling costs are recognized in cost of revenues. Accounts receivable allowances include sales returns and bad debt allowances. The Company monitors and tracks the amount of product returns and reduces revenue at the time of shipment for the estimated amount of such future returns, based on historical experience. The Company makes estimates evaluating its allowance for doubtful accounts. The Company continuously monitors collections and payments from its customers and maintains a provision for estimated credit losses based upon its historical experience and any specific customer collection issues that it has identified.
Research and Development	Research and Development Research and development costs are expensed as incurred and consist mainly of compensation-related expenses and project materials. The Company’s research and development efforts include numerous projects, which generally have a duration of 3 to 30 months. Acquired in-process research and development (“IPR&D”) expenses, which are capitalized at fair value as an intangible asset until the related project is completed, are then amortized over the estimated useful life of the product. The Company monitors projects and, if they are abandoned, the Company immediately writes them off.
Advertising Costs	Advertising Costs Advertising costs are expensed as incurred and were immaterial in 2015, 2014 and 2013.
Stock-Based Compensation	Stock-Based Compensation The accounting for share-based compensation expense requires the measurement and recognition of compensation expense for all share-based payment awards made to employees and directors based on estimated fair values. For restricted stock units (“RSUs”), the fair value is the fair value on the date of grant that normally vest over a three year period. The Company also provides employees the opportunity to purchase shares through an employee stock purchase plan. For shares issued under its employee stock purchase plan, the Company has estimated the fair value on the date of grant using the Black Scholes pricing model, which is affected by the Company’s stock price as well as assumptions regarding a number of complex and subjective variables. These variables include the Company’s expected stock price volatility over the term of the awards, expected life, risk free interest rate and expected dividends. The Company is also required to estimate forfeitures at the time of grant and revise those estimates in subsequent periods if actual forfeitures differ from those estimates. Management determined that blended volatility, a combination of historical and implied volatility, is more reflective of market conditions and a better indicator of expected volatility than historical or implied volatility alone. The assumptions used in calculating the fair value of share-based payment awards represent management’s best estimates, but these 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.
Accumulated Other Comprehensive Income	Accumulated Other Comprehensive Income For foreign subsidiaries where the functional currency is the local currency, assets and liabilities are translated into U.S. dollars at the current exchange rate on the balance sheet date. Revenue and expenses are translated at average rates of exchange prevailing during the year. Translation adjustments resulting from this process are recorded to Accumulated Other Comprehensive Income (“OCI”). Unrealized gains and losses on securities classified as available-for-sale are included in OCI in consolidated stockholders’ equity. For derivative instruments designated as cash-flow hedges, the effective portion of the derivative’s gain (loss) is initially reported as a component of OCI and is subsequently recognized in earnings when the hedged exposure is recognized in earnings.
Net Income Per Share	Net Income Per Share Basic net income per share is based on the weighted average number of common shares outstanding, and diluted net income per share is based on the weighted average number of common shares outstanding and all potential dilutive common equivalent shares outstanding. The dilutive effect of options is determined under the treasury stock method using the average market price for the period. Common equivalent shares are included in the per share calculations when the effect of their inclusion would be dilutive.
Cash and Cash Equivalents and Investments	Cash and Cash Equivalents and Investments All highly liquid investments with a maturity date of three months or less at the date of purchase are considered to be cash equivalents. The appropriate classification of investments in securities is determined at the time of purchase. Debt securities that the Company does not have the intent and ability to hold to maturity are classified as “available-for-sale” and are carried at fair value. Effective December 31, 2015, the Company changed the method of classification of its investments previously classified as long-term investments to short-term investments within current assets and the balances for the prior year have been reclassified to conform to the current year’s presentation. This new method classifies these securities as current or long-term based on the nature of the securities and the availability for use in current operations while the prior classification was based on the maturity dates of the investments. The Company believes this method is preferable because it is more reflective of the Company’s assessment of its overall liquidity position. The Company reviews its investment portfolio on a quarterly basis to identify and evaluate individual investments that have indications of possible impairment. The factors considered in determining whether a loss is other-than-temporary include: the length of time and extent to which fair market value has been below the cost basis, the financial condition and near-term prospects of the issuer, credit quality, and the Company’s ability to hold the investment for a period of time sufficient to allow for any anticipated recovery in fair value.
Concentrations of Credit Risk	Concentrations of Credit Risk The Company’s significant concentrations of credit risk consist principally of cash and cash equivalents, investments, forward exchange contracts and trade accounts receivable. The Company maintains cash and cash equivalents with financial institutions including some banks with which it had borrowings. The Company maintains investments primarily in U.S. Treasury and government agency securities and corporate debt securities. The Company enters into forward currency contracts with high credit-quality financial institutions in order to minimize credit risk exposure. The Company’s customers are primarily concentrated in the semiconductor industry, and a limited number of customers account for a significant portion of the Company’s revenues. The Company regularly monitors the creditworthiness of its customers and believes it has adequately provided for potential credit loss exposures. Credit is extended for all customers based primarily on financial condition, and collateral is not required. The Company had one customer comprising 18%, 19% and 17% of net revenues for 2015, 2014 and 2013, respectively, and another customer comprising 13%, 13% and 12% of net revenues for 2015, 2014, and 2013, respectively. During the years 2015, 2014 and 2013, approximately 69%, 70% and 68% of the Company’s net revenues, respectively, were from sales to semiconductor capital equipment manufacturers and semiconductor device manufacturers. There were two customers comprising 10% or more of the Company’s accounts receivable balance as of December 31, 2015.
Inventories	Inventories Inventories are stated at the lower of cost or market, cost being determined using a standard costing system which approximates cost based on a first-in, first-out method. The Company regularly reviews inventory quantities on hand and records a provision to write-down excess and obsolete inventory to its estimated net realizable value, if less than cost, based primarily on its estimated forecast of product demand.
Property, Plant and Equipment	Property, Plant and Equipment Property, plant and equipment are stated at cost. Expenditures for major renewals and betterments that extend the useful lives of property, plant and equipment are capitalized. Expenditures for maintenance and repairs are charged to expense as incurred. When assets are sold or otherwise disposed of, the cost and related accumulated depreciation are eliminated from the accounts and any resulting gain or loss is recognized in earnings. Depreciation is provided on the straight-line method over the estimated useful lives of twenty to thirty-one and one-half years for buildings and three to seven years for machinery and equipment, furniture and fixtures and office equipment, which includes enterprise resource planning software. Leasehold improvements are amortized over the shorter of the lease term or the estimated useful life of the leased asset.
Intangible Assets	Intangible Assets Intangible assets resulting from the acquisitions of businesses are estimated by management based on the fair value of assets acquired. These include acquired customer lists, technology, patents, trade names, covenants not to compete and IPR&D. Intangible assets are amortized from two to ten years on a straight-line basis which represents the estimated periods of benefit and the expected pattern of consumption.
Goodwill	Goodwill Goodwill is the amount by which the cost of acquired net assets exceeded the fair value of those net assets on the date of acquisition. The Company allocates goodwill to reporting units at the time of acquisition or when there is a change in the reporting structure and bases that allocation on which reporting units will benefit from the acquired assets and liabilities. Reporting units are defined as operating segments or one level below an operating segment, referred to as a component. In 2015, the Company reallocated its goodwill based upon a change in its reporting structure. There was no goodwill impairment as a result of this change in reporting units. The Company assesses goodwill for impairment on an annual basis as of October 31 or more frequently when events and circumstances occur indicating that the recorded goodwill may be impaired. The estimated fair value of the Company’s reporting units were based on discounted cash flow models derived from internal earnings and internal and external market forecasts. Determining fair value requires the exercise of significant judgment, including judgments about appropriate discount rates, perpetual growth rates and the amount and timing of expected future cash flows. Discount rates are based on a weighted average cost of capital (“WACC”), which represents the average rate a business must pay its providers of debt and equity. The WACC used to test goodwill is derived from a group of comparable companies. Assumptions in estimating future cash flows are subject to a high degree of judgment and complexity. The Company makes every effort to forecast these future cash flows as accurately as possible with the information available at the time the forecast is developed. The Company has the option of first assessing qualitative factors to determine whether it is necessary to perform the current two-step impairment test or the Company can perform the two-step impairment test without performing the qualitative assessment. For the reporting units that did not experience any significant adverse changes in their business or reporting structures or any other adverse changes, and the reporting unit’s fair value substantially exceeded its amount from the prior year assessment, the Company performed the qualitative “Step 0” assessment. In performing the qualitative Step 0 assessment, the Company considered certain events and circumstances specific to the reporting unit and to the entity as a whole, such as macroeconomic conditions, industry and market considerations, overall financial performance and cost factors when evaluating whether it is more likely than not that the fair value of the reporting unit is less than its carrying amount. For the remaining reporting units that did not meet these criteria, the Company performed the two-step goodwill impairment test. Under the two-step goodwill impairment test, the Company compared the fair value of each reporting unit to its respective carrying amount, including goodwill. If the fair value of the reporting unit exceeds the fair value, the second step of the goodwill impairment test must be completed to measure the amount of impairment loss, if any. The second step compares the implied fair value of goodwill with the carrying value of goodwill. The implied fair value is determined by allocating the fair value of the reporting unit to all of the assets and liabilities of that unit, the excess of the fair value of the amounts assigned to its assets and liabilities it the implied fair value of goodwill. If the implied fair value of goodwill is less than the carrying amount of goodwill, an impairment loss is recognized equal to the difference. As of October 31, 2015, the Company performed its annual impairment assessment of goodwill and determined that it is more likely than not that the fair values of the reporting units exceed their carrying amount.
Impairment of Long-Lived Assets	Impairment of Long-Lived Assets The Company evaluates the recoverability of its long-lived assets whenever events and changes in circumstances indicate that the carrying amount of an asset may not be fully recoverable. This periodic review may result in an adjustment of estimated depreciable lives or asset impairment. When indicators of impairment are present, the carrying values of the asset are evaluated in relation to their operating performance and future undiscounted cash flows of the underlying business. If the future undiscounted cash flows are less than their carrying value, impairment exists. The impairment is measured as the difference between the carrying value and the fair value of the underlying asset. Fair values are based on estimates of market prices and assumptions concerning the amount and timing of estimated future cash flows and assumed discount rates, reflecting varying degrees of perceived risk.
Foreign Exchange	Foreign Exchange The functional currency of the majority of the Company’s foreign subsidiaries is the applicable local currency. For those subsidiaries, assets and liabilities are translated to U.S. dollars at year-end exchange rates. Income and expense accounts are translated at the average exchange rates prevailing during the year. The resulting translation adjustments are included in accumulated other comprehensive income (loss) in consolidated stockholders’ equity. Foreign exchange transaction gains and losses, which arise from transaction activity, are reflected in selling, general and administrative expenses in the statement of operations. Net foreign exchange gains and losses resulting from re-measurement are included in selling general and administrative expense and were a loss of $1,388, a loss of $314 and a loss of $1,937, respectively, for the years ended December 31, 2015, 2014 and 2013. These amounts do not reflect the corresponding gain (loss) from foreign exchange contracts. See Note 7 “Derivatives” regarding foreign exchange contracts.
Income Taxes	Income Taxes The Company records income taxes using the asset and liability method. Deferred income tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective income tax bases, and also for operating loss and tax credit carry-forwards. On a quarterly basis, the Company evaluates both the positive and negative evidence that affects the realizability of net deferred tax assets and assesses the need for a valuation allowance. The future benefit to be derived from its deferred tax assets is dependent upon its ability to generate sufficient future taxable income in each jurisdiction of the right type to realize the assets. The Company records a valuation allowance to reduce its net deferred tax assets to the amount that is more likely than not to be realized. To the extent the Company establishes a valuation allowance an expense will be recorded as a component of the provision for income taxes on the statement of operations. During 2013, the Company decreased its valuation allowance by $395 primarily related to the expiration of U.S. capital loss carry-forwards. As a result, the valuation allowance was $27,102 at December 31, 2013. During 2014, the Company decreased its valuation allowance by $339 primarily related to the effective settlement of a foreign tax audit. As a result, the valuation allowance was $26,763 at December 31, 2014. During 2015, the Company decreased its valuation allowance by $20,636 primarily related to the expiration of U.S. capital loss carry-forwards. As a result, the valuation allowance was $6,127 at December 31, 2015. Accounting for income taxes requires a two-step approach to recognize and measure uncertain tax positions. The first step is to evaluate the tax position for recognition by determining if, based on the technical merits, it is more likely than not that the position will be sustained upon audit, including resolutions of related appeals or litigation processes, if any. The second step is to measure the tax benefit as the largest amount that is more than 50% likely of being realized upon ultimate settlement. The Company re-evaluates these uncertain tax positions on a quarterly basis. This evaluation is based on factors including, but not limited to, changes in facts or circumstances, changes in tax law, effectively settled issues under audit and new audit activity. Any change in these factors could result in the recognition of a tax benefit or an additional charge to the tax provision.
Recently Issued Accounting Pronouncements	In November 2015, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes.” Current generally accepted accounting principles require an entity to separate deferred income tax liabilities and assets into current and noncurrent amounts in a classified statement of financial position. The new amendments in this ASU require that deferred tax liabilities and assets be classified as noncurrent in a classified statement of financial position. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. Early application is permitted. The Company prospectively adopted this ASU during the fourth quarter of 2015. Adoption of this ASU did not have a material impact on the Company’s financial position and results of operations. In September 2015, the FASB issued ASU 2015-16, “Business Combinations (Topic 805)—Simplifying the Accounting for Measurement-Period Adjustments.” The new standard requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustments are identified, including the cumulative effect of the change in the provisional amount as if the accounting had been completed at the acquisition date. This ASU is effective for reporting periods beginning after December 15, 2015. Adoption of this ASU could have a material impact on the Company’s financial position and results of operations. In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330)—Simplifying the Measurement of Inventory.” The amendments in this ASU apply to all inventory that is measured using first-in, first-out or average cost. The new standard requires that an entity measure inventory within the scope of this update at the lower of cost and net realizable value. Net realizable value is the estimated selling prices in the ordinary course of business, less reasonably predictable costs of completion, disposal, and transportation. The amendments in this ASU are effective for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Adoption of this ASU is not expected to have a material impact on the Company’s financial position and results of operations. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements—Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern.” Under the new guidance, management will be required to assess an entity’s ability to continue as a going concern, and to provide related footnote disclosures in certain circumstances. The provisions of this ASU are effective for annual periods beginning after December 15, 2016, and for annual and interim periods thereafter. This ASU is not expected to have an impact on the Company’s financial statements or disclosures. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers (Topic 606),” which supersedes all existing revenue recognition requirements, including most industry-specific guidance. This standard requires a company to recognize revenue when it transfers goods and services to customers in an amount that reflects the consideration that the company expects to be entitled to in exchange for those goods or services. The ASU also requires additional disclosure about the nature, amount, timing and uncertainty of revenue and cash flows arising from customer contracts, including significant judgments and assets recognized from costs incurred to obtain or fulfill a contract. This pronouncement is effective for annual reporting periods beginning after December 15, 2017, including interim periods within that reporting period. The two permitted transition methods under the new standard are the full retrospective method, in which case the standard would be applied to each prior reporting period presented, or the modified retrospective method, in which case the cumulative effect of applying the standard would be recognized at the date of initial application. The Company has not yet selected a transition method. The Company is currently evaluating the requirements of ASU 2014-09 and we have not yet determined its impact on the Company’s consolidated financial statements.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	12 Months Ended
	Dec. 31, 2015
Adjustments in Balance Sheet Line Items [Member]
Summary of Adjustments of Prior Period Financial Statements	The table below reflects the adjustment in the balance sheet line items for the period ended December 31, 2014. December 31, 2014 As previously Adjustment As adjusted Short-term investments $ 129,594 $ 157,201 $ 286,795 Long-term investments $ 157,201 $ (157,201 ) $ —
Adjustments In Fair Value Of Short Term Investments [Member]
Summary of Adjustments of Prior Period Financial Statements	The fair value of short-term investments consists of the following: December 31, 2014 Available-for-sale investments: As previously Adjustment As adjusted Time deposits and certificates of deposit $ 20,900 $ 48 $ 20,948 Bankers acceptance drafts 82 — 82 Asset-backed securities — 75,674 75,674 Corporate obligations 24,020 64,669 88,689 Municipal bonds 2,099 1,254 3,353 U.S. agency obligations 82,493 15,556 98,049 $ 129,594 $ 157,201 $ 286,795

Investments (Tables)

Investments (Tables)	12 Months Ended
	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Fair Value of Investments Classified as Short-Term Available-for-Sale Investments	The fair value of investments classified as short-term consists of the following: Years Ended December 31, Available-for-sale investments: 2015 2014 Time deposits and certificates of deposit $ 11,892 $ 20,948 Bankers acceptance drafts 728 82 Asset-backed securities 124,997 75,674 Corporate obligations 165,109 88,689 Municipal bonds 8,355 3,353 U.S. agency obligations 119,582 98,049 $ 430,663 $ 286,795
Gross Unrealized Gains and (Losses) Aggregated by Investment Category Short-Term Securities	The following table shows the gross unrealized gains and (losses) aggregated by investment category for available-for-sale investments: As of December 31, 2015: Cost Gross Gross Estimated Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 11,893 $ — $ (1 ) $ 11,892 Bankers acceptance drafts 728 — — 728 Asset-backed securities 125,271 — (274 ) 124,997 Corporate obligations 165,445 5 (341 ) 165,109 Municipal bonds 8,346 13 (4 ) 8,355 U.S. agency obligations 119,699 3 (120 ) 119,582 $ 431,382 $ 21 $ (740 ) $ 430,663 As of December 31, 2014: Cost Gross Gross Estimated Short-term investments: Available-for-sale investments: Time deposits and certificates of deposit $ 20,949 $ — $ (1 ) $ 20,948 Bankers acceptance drafts 82 — — 82 Asset-backed securities 75,778 5 (109 ) 75,674 Corporate obligations 88,871 3 (185 ) 88,689 Municipal bonds 3,357 — (4 ) 3,353 U.S. agency obligations 98,051 16 (18 ) 98,049 $ 287,088 $ 24 $ (317 ) $ 286,795

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2015, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, Quoted Prices in (Level 1) Significant Other (Level 2) Significant (Level 3) Assets: Cash equivalents: Money market funds $ 106,099 $ 106,099 $ — $ — Bankers acceptance drafts 11 — 11 — Corporate obligations 330 — 330 — Available-for-sale investments: Time deposits and certificates of deposit 11,892 — 11,892 — Bankers acceptance drafts 728 — 728 — Asset-backed securities 124,997 — 124,997 — Corporate obligations 165,109 — 165,109 — Municipal bonds 8,355 — 8,355 — U.S. agency obligations 119,582 — 119,582 — Derivatives—currency forward contracts 1,486 — 1,486 — Total assets $ 538,589 $ 106,099 $ 432,490 $ — Liabilities: Derivatives—currency forward contracts $ 263 $ — $ 263 $ — Reported as follows: Assets: Cash and cash equivalents(1) $ 106,440 $ 106,099 $ 341 $ — Short-term investments 430,663 — 430,663 — Other current assets 1,486 — 1,486 — $ 538,589 $ 106,099 $ 432,490 $ — Liabilities: Other current liabilities $ 263 $ — $ 263 $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $110,118 and non-negotiable time deposits of $11,016 as of December 31, 2015. Assets and liabilities of the Company measured at fair value on a recurring basis as of December 31, 2014, are summarized as follows: Fair Value Measurements at Reporting Date Using Description December 31, Quoted Prices in (Level 1) Significant Other (Level 2) Significant (Level 3) Assets: Cash equivalents: Money market funds $ 129,092 $ 129,092 $ — $ — Bankers acceptance drafts 131 — 131 — Corporate obligations 700 — 700 — Available-for-sale investments: Time deposits and certificates of deposit 20,948 — 20,948 — Bankers acceptance drafts 82 — 82 — Asset-backed securities 75,674 — 75,674 — Corporate obligations 88,689 — 88,689 — Municipal bonds 3,353 — 3,353 — U.S. agency obligations 98,049 — 98,049 — Derivatives—currency forward contracts 2,110 — 2,110 — Total assets $ 418,828 $ 129,092 $ 289,736 $ — Liabilities: Derivatives—currency forward contracts $ — $ — $ — $ — Reported as follows: Assets: Cash and cash equivalents(1) $ 129,923 $ 129,092 $ 831 $ — Short-term investments(2) 286,795 — 286,795 — Other current assets 2,110 — 2,110 — $ 418,828 $ 129,092 $ 289,736 $ — Liabilities: Other current liabilities $ — $ — $ — $ — (1) The cash and cash equivalent amounts presented in the table above do not include cash of $167,517 and non-negotiable time deposits of $7,997 as of December 31, 2014. (2) Short-term investments as of December 31, 2014 includes investments with contractual maturities greater than one year from the date of purchase within short-term investments as management has the ability, if necessary, to liquidate any of its investments in order to meet the Company’s liquidity needs in the next 12 months.

Derivatives (Tables)

Derivatives (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Summary of Primary Net Hedging Positions and Corresponding Fair Values	The following tables provide a summary of the primary net hedging positions and corresponding fair values held as of December 31, 2015 and 2014: December 31, 2015 Currency Hedged (Buy/Sell) Gross Notional Fair Value (1) U.S. Dollar/Japanese Yen $ 26,848 $ (136 ) U.S. Dollar/South Korean Won 34,777 915 U.S. Dollar/Euro 10,987 19 U.S. Dollar/U.K. Pound Sterling 4,587 61 U.S. Dollar/Taiwan Dollar 12,790 364 Total $ 89,989 $ 1,223 December 31, 2014 Currency Hedged (Buy/Sell) Gross Notional Fair Value (1) U.S. Dollar/Japanese Yen $ 8,035 $ 1,107 U.S. Dollar/South Korean Won 12,512 372 U.S. Dollar/Euro 2,060 185 U.S. Dollar/U.K. Pound Sterling 1,308 70 U.S. Dollar/Taiwan Dollar 4,735 232 Total $ 28,650 $ 1,966 (1) Represents the receivable (payable) amount included in the consolidated balance sheet.
Summary of Fair Value Amounts of Company's Derivative Instruments	The following table provides a summary of the fair value amounts of the Company’s derivative instruments: Years Ended December 31, Derivatives Designated as Hedging Instruments 2015 2014 Derivative assets: Forward exchange contracts $ 1,486 $ 1,966 Derivative liabilities: Forward exchange contracts (263 ) — Total net derivative asset designated as hedging instruments (1) $ 1,223 $ 1,966 (1) The derivative asset of $1,486 and derivative liability of $(263) are classified in other current assets and other current liabilities in the consolidated balance sheet as of December 31, 2015. The derivative asset of $1,966 is classified in other current assets in the consolidated balance sheet as of December 31, 2014. These foreign exchange contracts are subject to a master netting agreement with one financial institution. However, the Company has elected to record these contracts on a gross basis in the balance sheet.
Summary of (Losses) Gains on Derivatives Designated as Hedging Instruments	The following table provides a summary of the (losses) gains on derivatives designated as hedging instruments: Years Ended December 31, Derivatives Designated as Cash Flow Hedging Instruments 2015 2014 2013 Forward exchange contracts: Net loss recognized in OCI (1) $ (3,748 ) $ (984 ) $ (48 ) Net gain (loss) reclassified from OCI into income (2) $ 3,520 $ (160 ) $ 1,086 (1) Net change in the fair value of the effective portion classified in OCI. (2) Effective portion classified as cost of products in 2015, 2014 and 2013.
Summary of (Losses) Gains on Derivatives Not Designated as Hedging Instruments	The following table provides a summary of the (losses) gains on derivatives not designated as hedging instruments: Years Ended December 31, Derivatives Not Designated as Hedging Instruments 2015 2014 2013 Forward exchange contracts: Net (loss) gain recognized in income (1) $ (40 ) $ 101 $ (215 ) (1) The Company enters into foreign exchange contracts to hedge against changes in the balance sheet, including accounts receivable and intercompany loans, for certain subsidiaries. These derivatives are not designated as hedging instruments.

Inventories (Tables)

Inventories (Tables)	12 Months Ended
	Dec. 31, 2015
Inventory Disclosure [Abstract]
Summary of Inventories	Inventories consist of the following: Years Ended December 31, 2015 2014 Raw material $ 78,352 $ 81,121 Work-in-process 23,297 26,604 Finished goods 50,982 47,444 $ 152,631 $ 155,169

Property, Plant and Equipment (

Property, Plant and Equipment (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Summary of Property, Plant and Equipment	Property, plant and equipment consist of the following: Years Ended December 31, 2015 2014 Land $ 8,535 $ 8,650 Buildings 68,881 66,885 Machinery and equipment 119,739 122,720 Furniture and fixtures, office equipment and software 61,490 59,972 Leasehold improvements 21,303 21,353 Construction in progress 4,171 3,647 284,119 283,227 Less: accumulated depreciation 215,263 210,451 $ 68,856 $ 72,776

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2015
Precisive, LLC [Member]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of acquisition: Current assets $ 693 Non-current assets 18 Intangible assets 5,110 Goodwill 7,042 Total assets acquired 12,863 Total current liabilities assumed (343 ) Fair value of assets acquired and liabilities assumed 12,520 Less cash acquired (435 ) Total purchase price, net of cash acquired $ 12,085
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	Substantially all of the purchase price was deductible for tax purposes. The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis, which approximates the pattern of use. Order backlog $ 50 18 months Customer relationships 1,430 8 years Exclusive patent license 2,600 10 years Trade names 210 10 years Developed technology 820 10 years $ 5,110
Granville-Phillips [Member]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of acquisition: Inventory $ 5,198 Property and equipment 299 Other assets 191 Intangible assets 38,850 Goodwill 42,587 Warranty liability (175 ) Total purchase price $ 86,950
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles are being amortized on a straight-line basis. Customer relationships $ 21,250 7 years Trademark and trade names 1,900 12 years Developed technology 15,700 9-12 years $ 38,850
Alter S.r.l [Member]
Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed	The following table summarizes the estimated fair value of the assets acquired and liabilities assumed at the date of the acquisition: Current assets $ 1,053 Property and equipment 211 Intangible assets 2,806 Goodwill 381 Other assets 67 Total assets acquired 4,518 Debt (Note 15) 770 Deferred taxes and other liabilities 1,301 Total liabilities assumed 2,071 Total purchase price 2,447 Cash acquired (21 ) Total purchase price, net of cash acquired $ 2,426
Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives	The following table reflects the allocation of the acquired intangible assets and related estimates of useful lives. These acquired intangibles will be amortized on a straight-line basis. Current developed technology $ 2,208 9 year useful life Trademarks and trade names 598 3 year useful life $ 2,806

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	The changes in the carrying amount of goodwill and accumulated impairment losses were as follows: 2015 2014 Gross Accumulated Net Gross Accumulated Net Beginning balance at January 1 $ 331,795 $ (139,414 ) $ 192,381 $ 290,323 $ (139,414 ) $ 150,909 Acquired goodwill(1) 8,017 — 8,017 41,993 — 41,993 Foreign currency translation (695 ) — (695 ) (521 ) — (521 ) Ending balance at December 31 $ 339,117 $ (139,414 ) $ 199,703 $ 331,795 $ (139,414 ) $ 192,381 (1) During 2015, the Company recorded $7,042 of goodwill related to the acquisition of Precisive. During the second quarter of 2015, the Company recorded a purchase accounting adjustment of $975 primarily related to an inventory valuation adjustment related to the acquisition of GP. During 2014, the Company recorded $41,612 of goodwill related to the acquisition of GP and recorded a purchase accounting adjustment of $381 related to the 2013 purchase of Alter S.r.l.
Intangible Assets	Components of the Company’s acquired intangible assets are comprised of the following: As of December 31, 2015 Gross Accumulated Foreign Currency Net Completed technology(1) $ 101,200 $ (82,330 ) $ (272 ) $ 18,598 Customer relationships(1) 37,251 (16,345 ) 10 20,916 Patents, trademarks, trade names and other(1) 30,396 (25,888 ) 5 4,513 $ 168,847 $ (124,563 ) $ (257 ) $ 44,027 (1) During 2015, the Company recorded $5,110 of separately identified intangible assets related to the acquisition of Precisive, of which $820 was completed technology, $1,430 was customer relationships and $2,860 was patents, trademarks, trade names and other. As of December 31, 2014 Gross Accumulated Foreign Currency Net Completed technology(1) $ 100,380 $ (79,875 ) $ 135 $ 20,640 Customer relationships(1) 35,821 (12,634 ) 280 23,467 Patents, trademarks, trade names and other(1) 27,536 (25,290 ) 36 2,282 $ 163,737 $ (117,799 ) $ 451 $ 46,389 (1) During 2014, the Company recorded $38,850 of separately identified intangible assets related to the acquisition of GP, of which $15,700 was completed technology, $21,250 was customer relationships and $1,900 was patents, trademarks, trade names and other.
Estimated Amortization Expense	Aggregate amortization expense related to acquired intangible assets for future years is: Year Amount 2016 $ 6,644 2017 6,561 2018 6,546 2019 6,504 2020 6,450 Thereafter 11,322

Other Assets (Tables)

Other Assets (Tables)	12 Months Ended
	Dec. 31, 2015
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Schedule of Other Assets	Years Ended December 31, 2015 2014 Other Current Assets: Income tax receivable $ 8,682 $ 10,322 Prepaid income tax 4,755 4,698 VAT tax receivable 3,264 3,417 Other 10,059 9,075 Total other current assets $ 26,760 $ 27,512 Other Assets: Deferred tax assets, net $ 19,252 $ 7,202 Long-term income tax receivable — 8,092 Other 1,998 1,912 Total other assets $ 21,250 $ 17,206

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Other Liabilities Disclosure [Abstract]
Schedule of Other Liabilities	Years Ended December 31, 2015 2014 Other Current Liabilities: Product warranties $ 5,205 $ 6,266 Deferred revenue 7,189 8,283 Other 22,965 21,240 Total other current liabilities $ 35,359 $ 35,789 Other Liabilities: Long-term income tax payable $ 4,483 $ 20,203 Accrued compensation 13,395 12,068 Other 3,604 6,324 Total other liabilities $ 21,482 $ 38,595

Product Warranties (Tables)

Product Warranties (Tables)	12 Months Ended
	Dec. 31, 2015
Guarantees [Abstract]
Product Warranty Activities	Product warranty activities were as follows: Years Ended December 31, 2015 2014 Beginning balance $ 6,266 $ 6,956 Provisions for product warranties 4,343 2,713 Direct charges to warranty liability (5,296 ) (3,271 ) Foreign currency translation (108 ) (132 ) Ending balance $ 5,205 $ 6,266

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Reconciliation of Company's Effective Tax Rate to U.S. Federal Statutory Rate	A reconciliation of the Company’s effective tax rate to the U.S. federal statutory rate is as follows: Years Ended December 31, 2015 2014 2013 U.S. Federal income tax statutory rate 35.0 % 35.0 % 35.0 % Federal tax credits (1.2 ) (1.0 ) (1.8 ) State income taxes, net of federal benefit 1.3 2.0 1.3 Effect of foreign operations taxed at various rates (6.4 ) (7.3 ) 0.3 Qualified production activity tax benefit (1.6 ) (1.8 ) (1.4 ) Deferred tax asset valuation allowance — (0.5 ) (0.7 ) Release of income tax reserves (including interest) (4.8 ) (10.7 ) — Foreign dividends, net of foreign tax credits 0.7 (1.0 ) — Income tax charges on accumulated foreign earnings — — 10.9 Tax benefit related to reinstatement of tax incentives — — (4.0 ) Other 0.3 0.4 0.1 23.3 % 15.1 % 39.7 %
Components of Income from Continuing Operations Before Income Taxes and Related Provision for Income Taxes	The components of income from continuing operations before income taxes and the related provision for income taxes consist of the following: Years Ended December 31, 2015 2014 2013 Income from continuing operations before income taxes: United States $ 90,401 $ 86,015 $ 29,546 Foreign 69,067 50,378 29,755 $ 159,468 $ 136,393 $ 59,301 Current taxes: United States $ 15,813 $ 8,361 $ 11,338 State 2,927 1,124 1,159 Foreign 18,021 5,866 14,117 36,761 15,351 26,614 Deferred taxes: United States (862 ) 8,908 (1,730 ) State and Foreign 1,272 (3,644 ) (1,359 ) 410 5,264 (3,089 ) Provision for income taxes $ 37,171 $ 20,615 $ 23,525
Significant Components of Deferred Tax Assets and Deferred Tax Liabilities	The significant components of the deferred tax assets and deferred tax liabilities are as follows: Years Ended December 31, 2015 2014 Deferred tax assets: Loss carry-forwards and credits $ 8,531 $ 30,523 Inventory and warranty reserves 15,404 15,015 Accounts receivable and other accruals 2,343 2,885 Stock-based compensation 3,713 3,255 Executive supplemental retirement benefits 3,947 3,321 Other — 283 Total deferred tax assets $ 33,938 $ 55,282 Deferred tax liabilities: Acquired intangible assets (9,434 ) (9,205 ) Depreciation and amortization (1,724 ) (2,609 ) Other (57 ) — Total deferred tax liabilities (11,215 ) (11,814 ) Valuation allowance (6,127 ) (26,763 ) Net deferred tax assets $ 16,596 $ 16,705
Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits	A reconciliation of the beginning and ending amount of gross unrecognized tax benefits is as follows: Years Ended December 31, 2015 2014 2013 Balance at beginning of year $ 19,610 $ 47,684 $ 40,674 Decreases for prior years (26 ) (13 ) — Increases for the current year 322 550 7,308 Reductions related to settlements with taxing authorities (15,370 ) (18,235 ) — Reductions related to expiration of statute of limitations (204 ) (10,376 ) (298 ) Balance at end of year $ 4,332 $ 19,610 $ 47,684

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	12 Months Ended
	Dec. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Activity for RSUs	The following table presents the activity for RSUs under the Plans: Year Ended December 31, 2015 Non-vested RSUs Weighted Non-vested RSUs — beginning of period 716,714 $ 28.67 Granted 394,952 $ 32.89 Vested (351,601 ) $ 28.59 Forfeited or expired (26,903 ) $ 29.84 Non-vested RSUs — end of period 733,162 $ 30.94
Summary of Activity for Options	The following table presents the activity for options under the Plans: Year Ended December 31, 2015 Options Weighted Outstanding — beginning of period 30,224 $ 19.67 Exercised (30,100 ) $ 19.68 Forfeited or expired (124 ) $ 18.16 Outstanding — end of period — $ — Exercisable at end of period — $ —
Effect of Recording Stock-Based Compensation	The following table reflects the effect of recording stock-based compensation for the years 2015, 2014 and 2013: Years Ended December 31, Stock-based compensation expense by type of award: 2015 2014 2013 Restricted stock units $ 11,885 $ 10,203 $ 12,982 Employee stock purchase plan 1,128 1,112 1,010 Total stock-based compensation 13,013 11,315 13,992 Tax effect on stock-based compensation (836 ) (331 ) (495 ) Net effect on net income $ 12,177 $ 10,984 $ 13,497 Effect on net earnings per share: Basic $ 0.23 $ 0.21 $ 0.25 Diluted $ 0.23 $ 0.21 $ 0.25
Pre-Tax Effect Within Consolidated Statements of Operations of Recording Stock-Based Compensation	The pre-tax effect within the consolidated statements of operations and comprehensive income of recording stock-based compensation for the years 2015, 2014 and 2013 was as follows: Years Ended December 31, 2015 2014 2013 Cost of revenues $ 1,814 $ 1,960 $ 2,038 Research and development expense 1,590 1,659 1,902 Selling, general and administrative expense 9,609 7,696 10,052 Total pre-tax stock-based compensation expense $ 13,013 $ 11,315 $ 13,992
Fair Value of Employees' Purchase Rights Estimated using Black-Scholes Option-Pricing Model	The fair value of the employees’ purchase plan rights was estimated using the Black-Scholes option-pricing model with the following weighted average assumptions: Years Ended December 31, Employee stock purchase plan rights: 2015 2014 2013 Expected life (years) 0.5 0.5 0.5 Risk-free interest rate 0.1 % 0.1 % 0.1 % Expected volatility 26.4 % 26.4 % 27.7 % Expected annual dividends per share $ 0.675 $ 0.655 $ 0.64

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share [Abstract]
Reconciliation of Basic and Diluted Net Income Per Share	The following is a reconciliation of basic to diluted net income per share: Years Ended December 31, Numerator: 2015 2014 2013 Net income $ 122,297 $ 115,778 $ 35,776 Denominator: Shares used in net income per common share — basic 53,282,000 53,232,000 53,061,000 Effect of dilutive securities: Stock options, restricted stock and employee stock purchase plan 278,000 283,000 420,000 Shares used in net income per common share — diluted 53,560,000 53,515,000 53,481,000 Net income per common share: Basic $ 2.30 $ 2.17 $ 0.67 Diluted $ 2.28 $ 2.16 $ 0.67

Business Segment, Geographic 49

Business Segment, Geographic Area, Product and Significant Customer Information (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Net Revenues by Reportable Segment	The following is net revenues by reportable segment: Years Ended December 31, 2015 2014 2013 Advanced Manufacturing Capital Equipment $ 662,911 $ 620,303 $ 509,008 Global Service 116,420 107,050 101,103 Asia Region Sales(1) 203,231 183,056 159,781 Other 79,523 82,709 73,235 Corporate, Eliminations (248,561 ) (212,249 ) (173,707 ) $ 813,524 $ 780,869 $ 669,420
Reconciliation of Segment Gross Profit to Consolidated Net Income	The following is a reconciliation of segment gross profit to consolidated net income: Years Ended December 31, 2015 2014 2013 Gross profit by reportable segment: Advanced Manufacturing Capital Equipment $ 286,149 $ 254,292 $ 185,105 Global Service 39,532 38,147 35,721 Asia Region Sales(1) 27,494 27,184 26,874 Other 23,869 27,896 25,894 Corporate and Eliminations (14,172 ) (9,753 ) (7,020 ) Total gross profit by reportable segment 362,872 337,766 266,574 Operating expenses: Research and development 68,305 62,888 63,570 Selling, general and administrative 129,087 131,828 142,014 Insurance reimbursement — — (1,071 ) Acquisition costs 30 499 171 Restructuring 2,074 2,464 1,364 Amortization of intangible assets 6,764 4,945 2,139 Income from operations 156,612 135,142 58,387 Net interest income 2,856 1,251 914 Income before income taxes 159,468 136,393 59,301 Provision for income taxes 37,171 20,615 23,525 Net income $ 122,297 $ 115,778 $ 35,776 (1) The Asia Region Sales segment does not represent total geographical Asia financial information. This sales operation only represents the sales from the resale of Advanced Manufacturing Capital Equipment and Other segment products in its respective region. The Advanced Manufacturing Capital Equipment and Other segments both have sales in this region as well. Accordingly, total geographical sales include sales from multiple reportable segments.
Schedule of Capital Expenditures, Depreciation and Amortization Expense and Segment Assets by Reportable Segment	The following is capital expenditures by reportable segment for the years ended December 31, 2015, 2014 and 2013: Advanced Global Asia Region Sales Other Corporate and Total December 31, 2015: Capital expenditures $ 7,958 $ 839 $ 451 $ 526 $ 2,640 $ 12,414 December 31, 2014: Capital expenditures $ 8,081 $ 1,032 $ 525 $ 1,632 $ 1,913 $ 13,183 December 31, 2013: Capital expenditures $ 8,139 $ 955 $ 628 $ 627 $ 2,061 $ 12,410 The following is depreciation and amortization expense by reportable segment for the years ended December 31, 2015, 2014 and 2013: Advanced Global Asia Region Sales Other Corporate and Total December 31, 2015: Depreciation and amortization $ 17,009 $ 1,005 $ 353 $ 1,114 $ 2,622 $ 22,103 December 31, 2014: Depreciation and amortization $ 15,171 $ 1,097 $ 477 $ 1,204 $ 2,565 $ 20,514 December 31, 2013: Depreciation and amortization $ 11,848 $ 1,103 $ 398 $ 1,265 $ 2,488 $ 17,102 Total income tax expense is impracticable to present by reportable segment because the necessary information is not available or used by the CODM.
Schedule of Net Revenues and Long-Lived Assets by Geographic Regions	Transfers between geographic areas are at negotiated transfer prices and have been eliminated from consolidated net revenues. Years Ended December 31, Net revenues: 2015 2014 2013 United States $ 458,313 $ 448,452 $ 363,948 Korea 106,909 97,323 75,401 Japan 62,879 61,092 56,978 Europe 79,927 80,659 77,910 Asia (excluding Korea and Japan) 105,496 93,343 95,183 $ 813,524 $ 780,869 $ 669,420 Years Ended December 31, Long-lived assets:(1) 2015 2014 United States $ 56,594 $ 57,701 Europe 5,783 6,099 Asia 8,952 10,887 $ 71,329 $ 74,687 (1) Long-lived assets include property, plant and equipment, net and certain other assets, excluding long-term tax-related accounts.
Summary of Goodwill Associated with Reportable Segments	Goodwill associated with each of our reportable segments is as follows: December 31, 2015 December 31, 2014 Reportable segment: Advanced Manufacturing Capital Equipment $ 174,344 $ 166,946 Global Service 19,826 19,728 Asia Region Sales — — Other 6,228 6,228 Foreign currency translation (695 ) (521 ) Total goodwill $ 199,703 $ 192,381
Worldwide Net Revenue for Each Group of Products	Worldwide net revenue for each group of products is as follows: Years Ended December 31, 2015 2014 2013 Instruments, Control and Vacuum Products $ 402,345 $ 383,863 $ 341,375 Power and Reactive Gas Products 350,469 335,271 273,357 Analytical Solutions Products 60,710 61,735 54,688 $ 813,524 $ 780,869 $ 669,420
Customers with Net Revenues Greater than 10% of Total Net Revenues	The Company had two customers with net revenues greater than 10% of total net revenues in the periods shown as follows: Years Ended December 31, 2015 2014 2013 Applied Materials, Inc. 17.8 % 19.1 % 17.0 % Lam Research Corporation 13.4 % 12.9 % 12.3 %

Restructurings (Tables)

Restructurings (Tables)	12 Months Ended
	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Schedule of Company's Restructuring Activity	The activity related to the Company’s restructuring accrual is shown below: 2015 2014 Balance at January 1 $ 92 $ — Charged to expense 2,074 2,464 Payments (1,359 ) (2,372 ) Balance at December 31 $ 807 $ 92

Commitments and Contingencies (

Commitments and Contingencies (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Minimum Lease Payments under Operating Lease	Minimum lease payments under operating leases are as follows: Year ending December 31, Operating Leases 2016 $ 7,315 2017 6,659 2018 5,127 2019 3,749 2020 2,513 Thereafter 2,266 Total minimum lease payments $ 27,629

Supplemental Financial Data (Ta

Supplemental Financial Data (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Schedule of Supplemental Financial Data	MKS Instruments, Inc. Supplemental Financial Data Quarter Ended March 31 June 30 Sept. 30, Dec. 31 (Table in thousands, except per share data) (Unaudited) 2015 Statement of Operations Data Net revenues $ 213,839 $ 217,966 $ 209,332 $ 172,387 Gross profit 97,046 98,798 94,229 72,799 Income from operations 47,010 46,034 41,363 22,205 Net income $ 33,786 $ 33,220 $ 29,769 $ 25,522 Net income per share: Basic $ 0.63 $ 0.62 $ 0.56 $ 0.48 Diluted $ 0.63 $ 0.62 $ 0.56 $ 0.48 Cash dividends paid per common share $ 0.165 $ 0.17 $ 0.17 $ 0.17 2014 Statement of Operations Data Net revenues $ 206,353 $ 184,697 $ 186,798 $ 203,021 Gross profit 89,372 79,635 79,325 89,434 Income from operations 37,778 30,660 28,150 38,554 Net income $ 31,245 $ 21,224 $ 29,117 $ 34,192 Net income per share: Basic $ 0.58 $ 0.40 $ 0.55 $ 0.64 Diluted $ 0.58 $ 0.40 $ 0.55 $ 0.64 Cash dividends paid per common share $ 0.16 $ 0.165 $ 0.165 $ 0.165

Business Description - Addition

Business Description - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015SegmentProduct
Number Of Product Groups And Reportable Segments [Abstract]
Number of product groups | Product	3
Number of reportable segments | Segment	4

Basis of Presentation - Schedul

Basis of Presentation - Schedule of Adjustment in Balance Sheet Line Items (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Short-term investments	$ 430,663	$ 286,795
As Previously Reported [Member]
Schedule of Investments [Line Items]
Short-term investments		129,594
Long-term investments		157,201
Adjustment [Member]
Schedule of Investments [Line Items]
Short-term investments		157,201
Long-term investments		$ (157,201)

Basis of Presentation - Summary

Basis of Presentation - Summary of Fair Value of Short-Term Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	$ 430,663	$ 286,795
Time Deposits and Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	11,892	20,948
Bankers Acceptance Drafts [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	728	82
Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	124,997	75,674
Corporate Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	165,109	88,689
Municipal Bonds [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	8,355	3,353
U.S. Agency Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	119,582	98,049
Short-Term Investments [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	430,663	286,795
Short-Term Investments [Member] | Time Deposits and Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	11,892	20,948
Short-Term Investments [Member] | Bankers Acceptance Drafts [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	728	82
Short-Term Investments [Member] | Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	124,997	75,674
Short-Term Investments [Member] | Corporate Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	165,109	88,689
Short-Term Investments [Member] | Municipal Bonds [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	8,355	3,353
Short-Term Investments [Member] | U.S. Agency Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments	$ 119,582	98,049
Short-Term Investments [Member] | As Previously Reported [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		129,594
Short-Term Investments [Member] | As Previously Reported [Member] | Time Deposits and Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		20,900
Short-Term Investments [Member] | As Previously Reported [Member] | Bankers Acceptance Drafts [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		82
Short-Term Investments [Member] | As Previously Reported [Member] | Corporate Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		24,020
Short-Term Investments [Member] | As Previously Reported [Member] | Municipal Bonds [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		2,099
Short-Term Investments [Member] | As Previously Reported [Member] | U.S. Agency Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		82,493
Short-Term Investments [Member] | Adjustment [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		157,201
Short-Term Investments [Member] | Adjustment [Member] | Time Deposits and Certificates of Deposit [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		48
Short-Term Investments [Member] | Adjustment [Member] | Asset-Backed Securities [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		75,674
Short-Term Investments [Member] | Adjustment [Member] | Corporate Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		64,669
Short-Term Investments [Member] | Adjustment [Member] | Municipal Bonds [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		1,254
Short-Term Investments [Member] | Adjustment [Member] | U.S. Agency Obligations [Member]
Schedule of Investments [Line Items]
Fair value of available-for-sale investments		$ 15,556

Summary of Significant Accoun56

Summary of Significant Accounting Policies - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Customer	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Schedule Of Significant Accounting Policies [Line Items]
Minimum period of company's research and development projects	3 months
Maximum period of company's research and development projects	30 months
Vesting period	3 years
Maximum maturity period of liquid investments	3 months
Amortization period of leasehold improvements	Shorter of the lease term or the estimated useful life of the leased asset
Goodwill Impairment	$ 0
Increase (decrease) in valuation allowance on state tax credit carryforwards	(20,636)	$ (339)	$ (395)
Valuation allowance	$ 6,127	$ 26,763	$ 27,102
Minimum percentage of recognition of tax benefits from uncertain tax positions	50.00%
Customer Concentration Risk [Member] | Accounts Receivable [Member]
Schedule Of Significant Accounting Policies [Line Items]
Number of customers comprising of Accounts Receivable | Customer	2
Customer Concentration Risk [Member] | Customer A [Member] | Sales Revenue, Net [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	18.00%	19.00%	17.00%
Customer Concentration Risk [Member] | Customer B [Member] | Sales Revenue, Net [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	13.00%	13.00%	12.00%
Customer Concentration Risk [Member] | Semiconductor Products [Member] | Sales Revenue, Net [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	69.00%	70.00%	68.00%
Selling, General and Administrative Expenses [Member]
Schedule Of Significant Accounting Policies [Line Items]
Net foreign exchange gains and losses from re-measurement	$ (1,388)	$ (314)	$ (1,937)
Minimum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Intangible assets amortized period	2 years
Minimum [Member] | Credit Concentration Risk [Member] | Accounts Receivable [Member]
Schedule Of Significant Accounting Policies [Line Items]
Concentration risk, percentage	10.00%
Minimum [Member] | Buildings [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	20 years
Minimum [Member] | Machinery and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Furniture and Fixtures [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Minimum [Member] | Office Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	3 years
Maximum [Member]
Schedule Of Significant Accounting Policies [Line Items]
Intangible assets amortized period	10 years
Maximum [Member] | Buildings [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	31 years 6 months
Maximum [Member] | Machinery and Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Furniture and Fixtures [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years
Maximum [Member] | Office Equipment [Member]
Schedule Of Significant Accounting Policies [Line Items]
Estimated useful lives	7 years

Investments - Fair Value of Inv

Investments - Fair Value of Investments Classified as Short-Term Available-for-Sale Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 430,663	$ 286,795
Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	11,892	20,948
Bankers Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	728	82
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	124,997	75,674
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	165,109	88,689
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	8,355	3,353
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Fair value of available-for-sale investments	$ 119,582	$ 98,049

Investments - Gross Unrealized

Investments - Gross Unrealized Gains and (Losses) Aggregated by Investment Category Short-Term Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	$ 430,663	$ 286,795
Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	11,892	20,948
Bankers Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	728	82
Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	124,997	75,674
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	165,109	88,689
Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	8,355	3,353
U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Estimated Fair Value	119,582	98,049
Short-Term Investments [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	431,382	287,088
Investments, Gross Unrealized Gains	21	24
Investments, Gross Unrealized (Losses)	(740)	(317)
Investments, Estimated Fair Value	430,663	286,795
Short-Term Investments [Member] | Time Deposits and Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	11,893	20,949
Investments, Gross Unrealized (Losses)	(1)	(1)
Investments, Estimated Fair Value	11,892	20,948
Short-Term Investments [Member] | Bankers Acceptance Drafts [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	728	82
Investments, Estimated Fair Value	728	82
Short-Term Investments [Member] | Asset-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	125,271	75,778
Investments, Gross Unrealized Gains		5
Investments, Gross Unrealized (Losses)	(274)	(109)
Investments, Estimated Fair Value	124,997	75,674
Short-Term Investments [Member] | Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	165,445	88,871
Investments, Gross Unrealized Gains	5	3
Investments, Gross Unrealized (Losses)	(341)	(185)
Investments, Estimated Fair Value	165,109	88,689
Short-Term Investments [Member] | Municipal Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	8,346	3,357
Investments, Gross Unrealized Gains	13
Investments, Gross Unrealized (Losses)	(4)	(4)
Investments, Estimated Fair Value	8,355	3,353
Short-Term Investments [Member] | U.S. Agency Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Investments, Cost	119,699	98,051
Investments, Gross Unrealized Gains	3	16
Investments, Gross Unrealized (Losses)	(120)	(18)
Investments, Estimated Fair Value	$ 119,582	$ 98,049

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives-currency forward contracts	$ 1,486	$ 1,966
Derivatives-currency forward contracts	263
Short-term investments	430,663	286,795
Available-for-sale investments	430,663	286,795
Other current assets	1,486	1,966
Other current liabilities	263
Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives-currency forward contracts	1,486	2,110
Total assets	538,589	418,828
Derivatives-currency forward contracts	263
Cash and cash equivalents	106,440	129,923
Short-term investments	430,663	286,795
Other current assets	1,486	2,110
Total current assets	538,589	418,828
Other current liabilities	263
Money Market Funds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	106,099	129,092
Bankers Acceptance Drafts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	11	131
Available-for-sale investments	728	82
Time Deposits and Certificates of Deposit [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	11,892	20,948
Asset-Backed Securities [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	124,997	75,674
U.S. Agency Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	119,582	98,049
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	106,099	129,092
Cash and cash equivalents	106,099	129,092
Total current assets	106,099	129,092
Quoted Prices in Active Markets for Identical Assets (Level 1) [Member] | Money Market Funds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	106,099	129,092
Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives-currency forward contracts	1,486	2,110
Total assets	432,490	289,736
Derivatives-currency forward contracts	263
Cash and cash equivalents	341	831
Short-term investments	430,663	286,795
Other current assets	1,486	2,110
Total current assets	432,490	289,736
Other current liabilities	263
Significant Other Observable Inputs (Level 2) [Member] | Bankers Acceptance Drafts [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	11	131
Available-for-sale investments	728	82
Significant Other Observable Inputs (Level 2) [Member] | Time Deposits and Certificates of Deposit [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	11,892	20,948
Significant Other Observable Inputs (Level 2) [Member] | Asset-Backed Securities [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	124,997	75,674
Significant Other Observable Inputs (Level 2) [Member] | U.S. Agency Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	119,582	98,049
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	165,109	88,689
Corporate Obligations [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	330	700
Available-for-sale investments	165,109	88,689
Corporate Obligations [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and cash equivalents	330	700
Available-for-sale investments	165,109	88,689
Municipal Bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	8,355	3,353
Municipal Bonds [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	8,355	3,353
Municipal Bonds [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fair Value Measurements, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale investments	$ 8,355	$ 3,353

Fair Value Measurements - Sch60

Fair Value Measurements - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Cash [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash/Non-negotiable time deposits - not subject to fair value disclosure requirements	$ 110,118	$ 167,517
Non-Negotiable Time Deposits [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash/Non-negotiable time deposits - not subject to fair value disclosure requirements	$ 11,016	$ 7,997

Derivatives - Additional Inform

Derivatives - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Maximum period for hedging a portion of forecasted foreign currency denominated intercompany sales of inventory	18 months
Gross notional values of outstanding forward foreign exchange contracts	$ 89,989	$ 28,650
Accumulated other comprehensive income realization period	12 months

Derivatives - Summary of Primar

Derivatives - Summary of Primary Net Hedging Positions and Corresponding Fair Values (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	$ 89,989	$ 28,650
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	1,223	1,966
Forward Exchange Contracts [Member] | U.S. Dollar/Japanese Yen [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	26,848	8,035
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	(136)	1,107
Forward Exchange Contracts [Member] | U.S. Dollar/South Korean Won [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	34,777	12,512
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	915	372
Forward Exchange Contracts [Member] | U.S. Dollar/Euro [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	10,987	2,060
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	19	185
Forward Exchange Contracts [Member] | U.S. Dollar/U.K. Pound Sterling [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	4,587	1,308
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	61	70
Forward Exchange Contracts [Member] | U.S. Dollar/Taiwan Dollar [Member]
Derivative [Line Items]
Currency Hedged (Buy/Sell), Gross Notional Value, Net	12,790	4,735
Currency Hedged (Buy/Sell), Fair Value, Asset/(Liability), Net	$ 364	$ 232

Derivatives - Summary of Fair V

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Forward exchange contracts, assets	$ 1,486	$ 1,966
Forward exchange contracts, liabilities	(263)
Total net derivative asset designated as hedging instruments	1,223	1,966
Derivatives Designated as Hedging Instruments [Member]
Derivatives, Fair Value [Line Items]
Forward exchange contracts, assets	1,486	1,966
Forward exchange contracts, liabilities	(263)
Total net derivative asset designated as hedging instruments	$ 1,223	$ 1,966

Derivatives - Summary of Fair64

Derivatives - Summary of Fair Value Amounts of Company's Derivative Instruments (Parenthetical) (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative asset classified in other current assets	$ 1,486	$ 1,966
Derivative liability classified in other current liabilities	$ (263)

Derivatives - Summary of (Losse

Derivatives - Summary of (Losses) Gains on Derivatives Designated as Hedging Instruments (Detail) - Forward Exchange Contracts [Member] - Cash Flow Hedging [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Net loss recognized in OCI	$ (3,748)	$ (984)	$ (48)
Net gain (loss) reclassified from OCI into income	$ 3,520	$ (160)	$ 1,086

Derivatives - Summary of (Los66

Derivatives - Summary of (Losses) Gains on Derivatives Not Designated as Hedging Instruments (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Net (loss) gain recognized in income	$ (40)	$ 101	$ (215)

Inventories - Summary of Invent

Inventories - Summary of Inventories (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Inventory Disclosure [Abstract]
Raw materials	$ 78,352	$ 81,121
Work-in-process	23,297	26,604
Finished goods	50,982	47,444
Inventories	$ 152,631	$ 155,169

Inventories - Additional Inform

Inventories - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Inventory Disclosure [Abstract]
Inventory related excess and obsolete charges	$ 13,602	$ 12,131	$ 21,671
Special charges for obsolete inventory			$ 6,423

Property, Plant and Equipment -

Property, Plant and Equipment - Summary of Property, Plant and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 284,119	$ 283,227
Less: accumulated depreciation	215,263	210,451
Property, plant and equipment, net	68,856	72,776
Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	8,535	8,650
Buildings [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	68,881	66,885
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	119,739	122,720
Furniture and Fixtures, Office Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	61,490	59,972
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	21,303	21,353
Construction in Progress [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 4,171	$ 3,647

Property, Plant and Equipment70

Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation of property, plant and equipment	$ 15,339	$ 15,569	$ 14,964

Acquisitions - Additional Infor

Acquisitions - Additional Information (Detail) - USD ($) $ in Thousands	Mar. 17, 2015	Mar. 12, 2013	Jun. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	May. 30, 2014
Business Acquisition [Line Items]
Payments to acquire business, net of cash acquired				$ 9,910	$ 86,950	$ 2,326
Precisive, LLC [Member]
Business Acquisition [Line Items]
Payments to acquire business, net of cash acquired	$ 12,085
Business acquisition, cash acquired	435
Business acquisition, deferred consideration payment	$ 2,600
Business acquisition, deferred consideration payment period	15 months
Business combination consideration price	$ 12,520
Granville-Phillips [Member]
Business Acquisition [Line Items]
Business combination consideration price							$ 86,950
Alter S.r.l [Member]
Business Acquisition [Line Items]
Payments to acquire business, net of cash acquired		$ 2,426	$ 2,058
Business acquisition, cash acquired		21
Business combination consideration price		2,447
Acquisition purchase price, net of cash acquired		$ 2,426
Acquisition date		Mar. 12, 2013

Acquisitions - Summary of Estim

Acquisitions - Summary of Estimated Fair Value of Assets Acquired and Liabilities Assumed (Detail) - USD ($) $ in Thousands	Mar. 17, 2015	Mar. 12, 2013	Jun. 30, 2013	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	May. 30, 2014
Business Acquisition [Line Items]
Goodwill				$ 199,703	$ 192,381	$ 150,909
Total purchase price, net of cash acquired				9,910	86,950	$ 2,326
Precisive, LLC [Member]
Business Acquisition [Line Items]
Current assets	$ 693
Non-current assets	18
Intangible assets	5,110
Goodwill	7,042			$ 7,042
Total assets acquired	12,863
Total current liabilities assumed	(343)
Total purchase price	12,520
Less cash acquired	(435)
Total purchase price, net of cash acquired	$ 12,085
Granville-Phillips [Member]
Business Acquisition [Line Items]
Inventory							$ 5,198
Property and equipment							299
Intangible assets							38,850
Goodwill					$ 41,612		42,587
Other assets							191
Warranty liability							(175)
Total purchase price							$ 86,950
Alter S.r.l [Member]
Business Acquisition [Line Items]
Current assets		$ 1,053
Property and equipment		211
Intangible assets		2,806
Goodwill		381
Other assets		67
Total assets acquired		4,518
Debt (Note 15)		770
Deferred taxes and other liabilities		1,301
Total liabilities assumed		2,071
Total purchase price		2,447
Less cash acquired		(21)
Total purchase price, net of cash acquired		$ 2,426	$ 2,058

Acquisitions - Allocation of Ac

Acquisitions - Allocation of Acquired Intangible Assets and Related Estimates of Useful Lives (Detail) - USD ($) $ in Thousands	Mar. 17, 2015	May. 30, 2014	Mar. 12, 2013	Dec. 31, 2015	Dec. 31, 2014
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets				2 years
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets				10 years
Precisive, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 5,110			$ 5,110
Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price		$ 38,850			$ 38,850
Alter S.r.l [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price			$ 2,806
Order Backlog [Member] | Precisive, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 50
Estimated useful life of finite-lived intangible assets	18 months
Customer Relationships [Member] | Precisive, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 1,430			$ 1,430
Estimated useful life of finite-lived intangible assets	8 years
Customer Relationships [Member] | Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price		$ 21,250			$ 21,250
Estimated useful life of finite-lived intangible assets		7 years
Exclusive Patent License [Member] | Precisive, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 2,600
Estimated useful life of finite-lived intangible assets	10 years
Trade names [Member] | Precisive, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 210
Estimated useful life of finite-lived intangible assets	10 years
Developed Technology [Member] | Precisive, LLC [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price	$ 820
Estimated useful life of finite-lived intangible assets	10 years
Developed Technology [Member] | Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price		$ 15,700
Developed Technology [Member] | Granville-Phillips [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets		9 years
Developed Technology [Member] | Granville-Phillips [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life of finite-lived intangible assets		12 years
Developed Technology [Member] | Alter S.r.l [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price			$ 2,208
Estimated useful life of finite-lived intangible assets			9 years
Trademarks and Trade Names [Member] | Granville-Phillips [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price		$ 1,900
Estimated useful life of finite-lived intangible assets		12 years
Trademarks and Trade Names [Member] | Alter S.r.l [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets, purchase price			$ 598
Estimated useful life of finite-lived intangible assets			3 years

Goodwill and Intangible Asset74

Goodwill and Intangible Assets - Goodwill (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Goodwill and Intangible Assets Disclosure [Abstract]
Beginning balance, Goodwill Gross Carrying Amount	$ 331,795	$ 290,323
Acquired goodwill, Gross Carrying Amount	8,017	41,993
Foreign currency translation, Gross Carrying Amount	(695)	(521)
Ending balance, Goodwill Gross Carrying Amount	339,117	331,795
Beginning balance, Accumulated Impairment (Loss)	(139,414)	(139,414)
Acquired goodwill, Accumulated Impairment (Loss)	0
Foreign currency translation, Accumulated Impairment (Loss)	0	0
Ending balance, Accumulated Impairment (Loss)	(139,414)	(139,414)
Beginning balance, Goodwill Net	192,381	150,909
Acquired goodwill, Net	8,017	41,993
Foreign currency translation, Net	(695)	(521)
Ending balance, Goodwill Net	$ 199,703	$ 192,381

Goodwill and Intangible Asset75

Goodwill and Intangible Assets - Goodwill (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2015	Mar. 17, 2015	May. 30, 2014	Dec. 31, 2013	Mar. 12, 2013
Goodwill [Line Items]
Goodwill		$ 192,381	$ 199,703			$ 150,909
Precisive, LLC [Member]
Goodwill [Line Items]
Goodwill			$ 7,042	$ 7,042
Granville-Phillips [Member]
Goodwill [Line Items]
Goodwill		41,612			$ 42,587
Acquisition purchase price	$ 975
Alter S.r.l [Member]
Goodwill [Line Items]
Goodwill							$ 381
Acquisition purchase price		$ 381

Goodwill and Intangible Asset76

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill and Intangible Assets Disclosure [Abstract]
Impairment charges	$ 0	$ 0	$ 0
Amortization of intangible assets	$ 6,764,000	$ 4,945,000	$ 2,139,000

Goodwill and Intangible Asset77

Goodwill and Intangible Assets - Intangible Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 168,847	$ 163,737
Accumulated Amortization	(124,563)	(117,799)
Foreign Currency Translation	(257)	451
Intangible assets, net	44,027	46,389
Completed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	101,200	100,380
Accumulated Amortization	(82,330)	(79,875)
Foreign Currency Translation	(272)	135
Intangible assets, net	18,598	20,640
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	37,251	35,821
Accumulated Amortization	(16,345)	(12,634)
Foreign Currency Translation	10	280
Intangible assets, net	20,916	23,467
Patents, Trademarks, Trade Names and Other [Member]
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	30,396	27,536
Accumulated Amortization	(25,888)	(25,290)
Foreign Currency Translation	5	36
Intangible assets, net	$ 4,513	$ 2,282

Goodwill and Intangible Asset78

Goodwill and Intangible Assets - Intangible Assets (Parenthetical) (Detail) - USD ($) $ in Thousands	Mar. 17, 2015	May. 30, 2014	Dec. 31, 2015	Dec. 31, 2014
Granville-Phillips [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets		$ 38,850		$ 38,850
Precisive, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 5,110		$ 5,110
Completed Technology [Member] | Granville-Phillips [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets				15,700
Completed Technology [Member] | Precisive, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets			820
Customer Relationships [Member] | Granville-Phillips [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets		$ 21,250		21,250
Customer Relationships [Member] | Precisive, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets	$ 1,430		1,430
Patents, Trademarks, Trade Names and Other [Member] | Granville-Phillips [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets				$ 1,900
Patents, Trademarks, Trade Names and Other [Member] | Precisive, LLC [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired intangible assets			$ 2,860

Goodwill and Intangible Asset79

Goodwill and Intangible Assets - Estimated Amortization Expense (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Goodwill and Intangible Assets Disclosure [Abstract]
2,016	$ 6,644
2,017	6,561
2,018	6,546
2,019	6,504
2,020	6,450
Thereafter	$ 11,322

Other Assets - Schedule of Othe

Other Assets - Schedule of Other Assets (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Other Current Assets:
Income tax receivable	$ 8,682	$ 10,322
Prepaid income tax	4,755	4,698
VAT tax receivable	3,264	3,417
Other	10,059	9,075
Total other current assets	26,760	27,512
Other Assets:
Deferred tax assets, net	19,252	7,202
Long-term income tax receivable		8,092
Other	1,998	1,912
Total other assets	$ 21,250	$ 17,206

Other Liabilities - Schedule of

Other Liabilities - Schedule of Other Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other Current Liabilities:
Product warranties	$ 5,205	$ 6,266	$ 6,956
Deferred revenue	7,189	8,283
Other	22,965	21,240
Total other current liabilities	35,359	35,789
Other Liabilities:
Long-term income tax payable	4,483	20,203
Accrued compensation	13,395	12,068
Other	3,604	6,324
Total other liabilities	$ 21,482	$ 38,595

Product Warranties - Product Wa

Product Warranties - Product Warranty Activities (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Guarantees [Abstract]
Beginning of period	$ 6,266	$ 6,956
Provision for product warranties	4,343	2,713
Direct charges to warranty liability	(5,296)	(3,271)
Foreign currency translation	(108)	(132)
End of period	$ 5,205	$ 6,266

Debt - Additional Information (

Debt - Additional Information (Detail) - Japan [Member]	12 Months Ended
	Dec. 31, 2015USD ($)Institution	Dec. 31, 2014USD ($)
Debt Instrument [Line Items]
Number of financial institutions for available lines of credit and borrowing arrangements | Institution	2
Aggregate borrowings expire and renewed	3 month intervals
Total available line of credit	$ 19,082,000
Total borrowings outstanding	$ 0	$ 0

Income Taxes - Reconciliation o

Income Taxes - Reconciliation of Company's Effective Tax Rate to U.S. Federal Statutory Rate (Detail)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
U.S. Federal income tax statutory rate	35.00%	35.00%	35.00%
Federal tax credits	(1.20%)	(1.00%)	(1.80%)
State income taxes, net of federal benefit	1.30%	2.00%	1.30%
Effect of foreign operations taxed at various rates	(6.40%)	(7.30%)	0.30%
Qualified production activity tax benefit	(1.60%)	(1.80%)	(1.40%)
Deferred tax asset valuation allowance		(0.50%)	(0.70%)
Release of income tax reserves (including interest)	(4.80%)	(10.70%)
Foreign dividends, net of foreign tax credits	0.70%	(1.00%)
Income tax charges on accumulated foreign earnings			10.90%
Tax benefit related to reinstatement of tax incentives			(4.00%)
Other	0.30%	0.40%	0.10%
Total	23.30%	15.10%	39.70%

Income Taxes - Components of In

Income Taxes - Components of Income from Continuing Operations Before Income Taxes and Related Provision for Income Taxes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income from continuing operations before income taxes:
United States	$ 90,401	$ 86,015	$ 29,546
Foreign	69,067	50,378	29,755
Income from continuing operations before income taxes	159,468	136,393	59,301
Current taxes:
United States	15,813	8,361	11,338
State	2,927	1,124	1,159
Foreign	18,021	5,866	14,117
Current taxes, Total	36,761	15,351	26,614
Deferred taxes:
United States	(862)	8,908	(1,730)
State and Foreign	1,272	(3,644)	(1,359)
Deferred taxes, Total	410	5,264	(3,089)
Provision for income taxes	$ 37,171	$ 20,615	$ 23,525

Income Taxes - Significant Comp

Income Taxes - Significant Components of Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Deferred tax assets:
Loss carry-forwards and credits	$ 8,531	$ 30,523
Inventory and warranty reserves	15,404	15,015
Accounts receivable and other accruals	2,343	2,885
Stock-based compensation	3,713	3,255
Executive supplemental retirement benefits	3,947	3,321
Other		283
Total deferred tax assets	33,938	55,282
Deferred tax liabilities:
Acquired intangible assets	(9,434)	(9,205)
Depreciation and amortization	(1,724)	(2,609)
Other	(57)
Total deferred tax liabilities	(11,215)	(11,814)
Valuation allowance	(6,127)	(26,763)	$ (27,102)
Net deferred tax assets	$ 16,596	$ 16,705

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Taxes [Line Items]
Gross Massachusetts tax research other tax credit carryforwards	$ 8,933
Tax credit expiration period	2,029
Gross unrecognized tax benefits excluding interest and penalties	$ 4,332	$ 19,610	$ 47,684	$ 40,674
Net unrecognized tax benefit excluding interest and penalties that would impact effective tax rate	4,326
Net benefit to income tax expense, excluding interest and penalties, due to discrete reserve releases	7,304
Accrued interest on unrecognized tax benefits	157	578	2,159
Net unrecognized tax benefits, excluding interest and penalties, related to foreign tax positions	$ 923
Income tax examination, description	The Company is subject to examination by U.S. federal, state and foreign tax authorities. The United States Internal Revenue Service commenced an examination of our U.S. federal tax filings for tax years 2011 through 2013 during the quarter ended March 31, 2015.
Change in valuation allowance	$ (20,636)	$ (339)	$ (395)
Undistributed earnings in foreign subsidiaries	$ 450,000
Income tax holiday tax rate	9.00%	9.00%	7.00%
Other Operations [Member]
Income Taxes [Line Items]
Income tax holiday tax rate	16.00%
State and Foreign [Member]
Income Taxes [Line Items]
Operating loss carry forwards	$ 7,784
State and Foreign [Member] | Indefinite [Member]
Income Taxes [Line Items]
Operating loss carry forwards	5,000
State and Foreign [Member] | 2021 [Member]
Income Taxes [Line Items]
Operating loss carry forwards	$ 2,784
Earliest Tax Year [Member]
Income Taxes [Line Items]
Income tax examination period	2,011
Latest Tax Year [Member]
Income Taxes [Line Items]
Income tax examination period	2,013

Income Taxes - Reconciliation88

Income Taxes - Reconciliation of Beginning and Ending Amount of Gross Unrecognized Tax Benefits (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Balance at beginning of year	$ 19,610	$ 47,684	$ 40,674
Decreases for prior years	(26)	(13)
Increases for the current year	322	550	7,308
Reductions related to settlements with taxing authorities	(15,370)	(18,235)
Reductions related to expiration of statute of limitations	(204)	(10,376)	(298)
Balance at end of year	$ 4,332	$ 19,610	$ 47,684

Stockholder's Equity - Addition

Stockholder's Equity - Additional Information (Detail) - USD ($)	Feb. 08, 2016	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	Jul. 25, 2011
Stockholders Equity [Line Items]
Common stock, value of shares authorized to repurchase													$ 200,000,000
Stock repurchase, shares										369,133	727,912
Value of shares repurchased										$ 13,294,000	$ 20,809,000	$ 2,875,000
Average price of repurchased shares										$ 36.01	$ 28.59
Cash dividends per common share		$ 0.170	$ 0.170	$ 0.170	$ 0.165	$ 0.165	$ 0.165	$ 0.165	$ 0.160	$ 0.675	$ 0.655	$ 0.640
Dividend payment to common shareholders										$ 35,969,000	$ 34,851,000	$ 33,975,000
Subsequent Event [Member]
Stockholders Equity [Line Items]
Dividend declared date	Feb. 8, 2016
Cash dividend to be paid	$ 0.17
Dividend to be paid date	Mar. 11, 2016
Dividend declared, shareholders of record date	Feb. 29, 2016

Stock-Based Compensation - Addi

Stock-Based Compensation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares issued	53,199,720	53,154,666
Vesting period	3 years
Number of stock options outstanding	0	30,224
Number of stock options exercisable	0
Tax effect from stock-based plans	$ 837,000	$ 331,000	$ 495,000
Capitalization of share based payment costs	$ 471,000	$ 471,000
Options granted	0	0	0
Total intrinsic value of options exercised	$ 494,000	$ 958,000	$ 684,000
Weighted average fair value per share of employee stock purchase plan rights, granted	$ 8.16	$ 6.37	$ 5.76
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value per share of employee stock purchase plan rights, granted	$ 32.89
Total intrinsic value of options exercised and fair value of RSUs vested	$ 12,868,000	$ 12,106,000	$ 19,221,000
Unrecognized compensation cost	$ 11,585,000
Estimated weighted average amortization period	9 months 26 days
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 day
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	13 months
Restricted Stock Units (RSUs) [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted to employees under plans prior to 2001, vested after one year	33.30%	33.30%	33.30%
RSUs Granted to Employees [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award vesting period description	Employees who are at least 60 years old and have a minimum of 10 Years of Service (as defined in the applicable RSU agreement) are expensed immediately.
Minimum years of service for RSU	10 years
RSUs Granted to Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award vesting period description	Earliest of (1) one day prior to the next annual meeting, (2) 13 months from date of grant, or (3) the effective date of an acquisition.
Employee Stock Purchase Plan - Second Amended and Restated [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	400,000
Percentage of Common Stock through payroll deductions	10.00%
Amount of payroll deduction	$ 21,250
Percentage of closing price of the Common Stock	85.00%
Common stock, shares issued		20,053
Common stock, exercise price		$ 24.52
Employee Stock Purchase Plan - Second Amended and Restated [Member] | Offer Terminate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of closing price of the Common Stock	85.00%
Employee Stock Purchase Plan - Third Amended and Restated [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	1,950,000
Percentage of payroll deduction to compensation	Up to 10%
Percentage of Common Stock through payroll deductions	10.00%
Amount of payroll deduction	$ 21,250
Percentage of closing price of the Common Stock	85.00%
Common stock, shares issued		69,474
Common stock, exercise price		$ 24.52
Employee Stock Purchase Plan - Third Amended and Restated [Member] | Offer Terminate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of closing price of the Common Stock	85.00%
2014 ESPP Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	2,500,000
Percentage of payroll deduction to compensation	Up to 10%
Percentage of Common Stock through payroll deductions	10.00%
Amount of payroll deduction	$ 21,250
Percentage of closing price of the Common Stock	85.00%
Common stock, shares issued	140,531	82,481
Common stock, exercise price		$ 24.33
Shares reserved for future issuance	2,276,988
2014 ESPP Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, exercise price	$ 30.74
2014 ESPP Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, exercise price	$ 31.34
2014 ESPP Plan [Member] | Offer Terminate [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of closing price of the Common Stock	85.00%
Stock Incentive Plan 2014 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares reserved for future issuance	16,953,488
Shares available for future grant	18,000,000
Percentage of exercise price fair value option grant in period	100.00%
Number of shares returned for each common stock	2.4
Stock Incentive Plans 2001 and After [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of exercise price fair value option grant in period	100.00%
Stock options granted to employees under plans prior to 2001, vested per quarter thereafter	6.25%
Stock options expired	10 years
Stock Incentive Plans 2001 and After [Member] | Share-based Compensation Award, Tranche One [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options granted to employees under plans prior to 2001, vested after one year	25.00%
1997 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share based compensation arrangement by share based payment award vesting period description	Options granted to directors generally vested at the earliest of (1) one day prior to the next annual meeting, (2) 13 months from the date of grant, or (3) the effective date of an acquisition.
Number of stock options outstanding	0
1997 Director Plan [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	1 day
1997 Director Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period	13 months
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash received from employees as a result of employee stock option exercises	$ 592,000	$ 1,605,000
Tax effect from stock-based plans	$ 21,000	$ 175,000

Stock-Based Compensation - Summ

Stock-Based Compensation - Summary of Activity for RSUs (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested RSUs - end of period	733,000
Weighted Average Grant Date Fair Value, Granted	$ 8.16	$ 6.37	$ 5.76
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Non-vested RSUs - beginning of period	716,714
Granted	394,952
Vested	(351,601)
Forfeited or expired	(26,903)
Non-vested RSUs - end of period	733,162	716,714
Weighted Average Grant Date Fair Value, Beginning of period	$ 28.67
Weighted Average Grant Date Fair Value, Granted	32.89
Weighted Average Grant Date Fair Value, Vested	28.59
Weighted Average Grant Date Fair Value, Forfeited or expired	29.84
Weighted Average Grant Date Fair Value, end of period	$ 30.94	$ 28.67

Stock-Based Compensation - Su92

Stock-Based Compensation - Summary of Activity for Options (Detail)	12 Months Ended
	Dec. 31, 2015$ / sharesshares
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Options, Outstanding - beginning of period	30,224
Options, Exercised	(30,100)
Options, Forfeited or expired	(124)
Options, Outstanding - end of period	0
Options, Exercisable at end of period	0
Weighted Average Exercise Price, Outstanding - beginning of period | $ / shares	$ 19.67
Weighted Average Exercise Price, Exercised | $ / shares	19.68
Weighted Average Exercise Price, Forfeited or expired | $ / shares	18.16
Weighted Average Exercise Price, Exercisable at end of period | $ / shares	$ 0

Stock-Based Compensation - Effe

Stock-Based Compensation - Effect of Recording Stock-Based Compensation (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 13,013	$ 11,315	$ 13,992
Tax effect on stock-based compensation	(836)	(331)	(495)
Net effect on net income	$ 12,177	$ 10,984	$ 13,497
Basic	$ 0.23	$ 0.21	$ 0.25
Diluted	$ 0.23	$ 0.21	$ 0.25
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 11,885	$ 10,203	$ 12,982
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation	$ 1,128	$ 1,112	$ 1,010

Stock-Based Compensation - Pre-

Stock-Based Compensation - Pre-Tax Effect Within Consolidated Statements of Operations of Recording Stock-Based Compensation (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	$ 13,013	$ 11,315	$ 13,992
Cost of revenues [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	1,814	1,960	2,038
Research and Development Expense [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	1,590	1,659	1,902
Selling, General and Administrative Expenses [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]
Total pre-tax stock-based compensation expense	$ 9,609	$ 7,696	$ 10,052

Stock-Based Compensation - Fair

Stock-Based Compensation - Fair Value of Employees' Purchase Rights Estimated Using Black-Scholes Option-Pricing Model (Detail) - $ / shares	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
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Expected life (years)									6 months	6 months	6 months
Risk-free interest rate									0.10%	0.10%	0.10%
Expected volatility									26.40%	26.40%	27.70%
Expected annual dividends per share	$ 0.170	$ 0.170	$ 0.170	$ 0.165	$ 0.165	$ 0.165	$ 0.165	$ 0.160	$ 0.675	$ 0.655	$ 0.640

Employee Benefit Plans - Additi

Employee Benefit Plans - Additional Information (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2015USD ($)Plan	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Compensation and Retirement Disclosure [Abstract]
Employee contribution to Company's profit sharing plan percentage	1.00%
Employee contribution to Company's profit sharing plan percentage	50.00%
Minimum age limit for specified additional amount	50 years
Employers contribution percentage limit	50.00%
Employees maximum contribution as a percentage of salary	6.00%
Company's contributions	$ 2,667	$ 2,484	$ 2,334
Foreign defined benefit plan | Plan	1
Bonus expense	$ 14,599	14,434	16,006
Supplemental retirement benefits cost	1,704	2,258	$ 4,988
Accumulated benefit obligation	$ 10,645	$ 8,941

Net Income Per Share - Reconcil

Net Income Per Share - Reconciliation of Basic and Diluted Net Income Per Share (Detail) - 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
Numerator:
Net income	$ 25,522	$ 29,769	$ 33,220	$ 33,786	$ 34,192	$ 29,117	$ 21,224	$ 31,245	$ 122,297	$ 115,778	$ 35,776
Denominator:
Shares used in net income per common share - basic									53,282,000	53,232,000	53,061,000
Effect of dilutive securities:
Stock options, restricted stock and employee stock purchase plan									278,000	283,000	420,000
Shares used in net income per common share - diluted									53,560,000	53,515,000	53,481,000
Net income per common share:
Basic	$ 0.48	$ 0.56	$ 0.62	$ 0.63	$ 0.64	$ 0.55	$ 0.40	$ 0.58	$ 2.30	$ 2.17	$ 0.67
Diluted	$ 0.48	$ 0.56	$ 0.62	$ 0.63	$ 0.64	$ 0.55	$ 0.40	$ 0.58	$ 2.28	$ 2.16	$ 0.67

Net Income Per Share - Addition

Net Income Per Share - Additional Information (Detail) - shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings Per Share [Abstract]
Number of restricted stock units outstanding	733,000
Number of stock options outstanding	0	30,224
Stock options and restricted stock units outstanding		747,000	868,000
Number of shares excluded from computation of diluted earnings per share	0	600	83,000

Business Segment, Geographic 99

Business Segment, Geographic Area, Product and Significant Customer Information - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015CustomerSegmentProduct
Segment Reporting [Abstract]
Number of reportable segments | Segment	4
Number of product groups | Product	3
Number of customers with net revenues greater than 10% of total net revenues | Customer	2
Entity wide net revenue major customer percentage minimum	10.00%

Business Segment, Geographic100

Business Segment, Geographic Area, Product and Significant Customer Information - Net Revenues by Reportable Segment (Detail) - 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
Segment Reporting Information [Line Items]
Total net revenues	$ 172,387	$ 209,332	$ 217,966	$ 213,839	$ 203,021	$ 186,798	$ 184,697	$ 206,353	$ 813,524	$ 780,869	$ 669,420
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Total net revenues									662,911	620,303	509,008
Operating Segments [Member] | Global Service [Member]
Segment Reporting Information [Line Items]
Total net revenues									116,420	107,050	101,103
Operating Segments [Member] | Asia Region Sales [Member]
Segment Reporting Information [Line Items]
Total net revenues									203,231	183,056	159,781
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Total net revenues									79,523	82,709	73,235
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Total net revenues									$ (248,561)	$ (212,249)	$ (173,707)

Business Segment, Geographic101

Business Segment, Geographic Area, Product and Significant Customer Information - Reconciliation of Segment Gross Profit to Consolidated Net Income (Detail) - 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
Segment Reporting Information [Line Items]
Gross profit	$ 72,799	$ 94,229	$ 98,798	$ 97,046	$ 89,434	$ 79,325	$ 79,635	$ 89,372	$ 362,872	$ 337,766	$ 266,574
Research and development									68,305	62,888	63,570
Selling, general and administrative									129,087	131,828	142,014
Insurance reimbursement											(1,071)
Acquisition costs									30	499	171
Restructuring									2,074	2,464	1,364
Amortization of intangible assets									6,764	4,945	2,139
Income from operations	22,205	41,363	46,034	47,010	38,554	28,150	30,660	37,778	156,612	135,142	58,387
Net interest income									2,856	1,251	914
Income before income taxes									159,468	136,393	59,301
Provision for income taxes									37,171	20,615	23,525
Net income	$ 25,522	$ 29,769	$ 33,220	$ 33,786	$ 34,192	$ 29,117	$ 21,224	$ 31,245	122,297	115,778	35,776
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Gross profit									286,149	254,292	185,105
Operating Segments [Member] | Global Service [Member]
Segment Reporting Information [Line Items]
Gross profit									39,532	38,147	35,721
Operating Segments [Member] | Asia Region Sales [Member]
Segment Reporting Information [Line Items]
Gross profit									27,494	27,184	26,874
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Gross profit									23,869	27,896	25,894
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Gross profit									$ (14,172)	$ (9,753)	$ (7,020)

Business Segment, Geographic102

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Capital Expenditures, Depreciation and Amortization Expense and Segment Assets by Reportable Segment (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Capital expenditures	$ 12,414	$ 13,183	$ 12,410
Depreciation and amortization	22,103	20,514	17,102
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Capital expenditures	7,958	8,081	8,139
Depreciation and amortization	17,009	15,171	11,848
Operating Segments [Member] | Global Service [Member]
Segment Reporting Information [Line Items]
Capital expenditures	839	1,032	955
Depreciation and amortization	1,005	1,097	1,103
Operating Segments [Member] | Asia Region Sales [Member]
Segment Reporting Information [Line Items]
Capital expenditures	451	525	628
Depreciation and amortization	353	477	398
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Capital expenditures	526	1,632	627
Depreciation and amortization	1,114	1,204	1,265
Corporate and Eliminations [Member]
Segment Reporting Information [Line Items]
Capital expenditures	2,640	1,913	2,061
Depreciation and amortization	$ 2,622	$ 2,565	$ 2,488

Business Segment, Geographic103

Business Segment, Geographic Area, Product and Significant Customer Information - Schedule of Net Revenues and Long-Lived Assets by Geographic Regions (Detail) - 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
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues	$ 172,387	$ 209,332	$ 217,966	$ 213,839	$ 203,021	$ 186,798	$ 184,697	$ 206,353	$ 813,524	$ 780,869	$ 669,420
Long-lived assets	71,329				74,687				71,329	74,687
United States [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									458,313	448,452	363,948
Long-lived assets	56,594				57,701				56,594	57,701
Korea [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									106,909	97,323	75,401
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									62,879	61,092	56,978
Europe [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									79,927	80,659	77,910
Long-lived assets	5,783				6,099				5,783	6,099
Asia (Excluding Korea and Japan) [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Net revenues									105,496	93,343	$ 95,183
Long-lived assets	$ 8,952				$ 10,887				$ 8,952	$ 10,887

Business Segment, Geographic104

Business Segment, Geographic Area, Product and Significant Customer Information - Summary of Goodwill Associated with Reportable Segments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Goodwill	$ 199,703	$ 192,381	$ 150,909
Operating Segments [Member] | Advanced Manufacturing Capital Equipment [Member]
Segment Reporting Information [Line Items]
Goodwill	174,344	166,946
Operating Segments [Member] | Global Service [Member]
Segment Reporting Information [Line Items]
Goodwill	19,826	19,728
Operating Segments [Member] | Other [Member]
Segment Reporting Information [Line Items]
Goodwill	6,228	6,228
Segment Reconciling Items [Member] | Foreign Currency Translation [Member]
Segment Reporting Information [Line Items]
Goodwill	$ (695)	$ (521)

Business Segment, Geographic105

Business Segment, Geographic Area, Product and Significant Customer Information - Worldwide Net Revenue for Each Group of Products (Detail) - 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
Revenue from External Customer [Line Items]
Net sales from product groups	$ 172,387	$ 209,332	$ 217,966	$ 213,839	$ 203,021	$ 186,798	$ 184,697	$ 206,353	$ 813,524	$ 780,869	$ 669,420
Instruments, Control and Vacuum Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									402,345	383,863	341,375
Power and Reactive Gas Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									350,469	335,271	273,357
Analytical Solutions Products [Member]
Revenue from External Customer [Line Items]
Net sales from product groups									$ 60,710	$ 61,735	$ 54,688

Business Segment, Geographic106

Business Segment, Geographic Area, Product and Significant Customer Information - Customers with Net Revenues Greater than 10% of Total Net Revenues (Detail) - Customer Concentration Risk [Member] - Sales Revenue, Net [Member]	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Applied Materials Inc [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	17.80%	19.10%	17.00%
Lam Research Corporation [Member]
Revenue, Major Customer [Line Items]
Percentage of total net revenues	13.40%	12.90%	12.30%

Restructurings - Additional Inf

Restructurings - Additional Information (Detail) $ in Thousands	3 Months Ended	12 Months Ended
	Sep. 30, 2014USD ($)	Dec. 31, 2015USD ($)People	Dec. 31, 2014USD ($)PeopleFacility	Dec. 31, 2013USD ($)
Restructuring Cost and Reserve [Line Items]
Restructuring charges		$ 2,074	$ 2,464	$ 1,364
Approximate number of workforce reduction from the company's headcount | People		266	131
Colorado [Member]
Restructuring Cost and Reserve [Line Items]
Number of facilities closing | Facility			1
Proceeds from sale of building, net of commissions	$ 1,316

Restructurings - Schedule of Co

Restructurings - Schedule of Company's Restructuring Activity (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring and Related Activities [Abstract]
Balance at January 1	$ 92
Charged to expense	2,074	$ 2,464	$ 1,364
Payments	(1,359)	(2,372)
Balance at December 31	$ 807	$ 92

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Lease expiration date		2,022
Rental expenses under operating leases	$ 7,845	$ 6,909	$ 7,896
Purchase commitments covered by aggregate value	$ 121,820
Purchase commitments	Less than one year

Commitments and Contingencie110

Commitments and Contingencies - Minimum Lease Payments under Operating Leases (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Commitments and Contingencies Disclosure [Abstract]
2,016	$ 7,315
2,017	6,659
2,018	5,127
2,019	3,749
2,020	2,513
Thereafter	2,266
Total minimum lease payments	$ 27,629

Subsequent Event - Announcem111

Subsequent Event - Announcement of the Acquisition of Newport Corporation - Additional Information (Detail) - Subsequent Event [Member] - Newport [Member]	Feb. 23, 2016USD ($)$ / shares
Subsequent Event [Line Items]
Price per share | $ / shares	$ 23
Acquisition of business, cash acquired gross	$ 980,000,000
Asset-Based Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Asset-based revolving credit facility	50,000,000
Maximum [Member]
Subsequent Event [Line Items]
Committed debt financing	$ 800,000,000

Supplemental Financial Data (De

Supplemental Financial Data (Detail) - 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
Statement of Operations Data
Net revenues	$ 172,387	$ 209,332	$ 217,966	$ 213,839	$ 203,021	$ 186,798	$ 184,697	$ 206,353	$ 813,524	$ 780,869	$ 669,420
Gross profit	72,799	94,229	98,798	97,046	89,434	79,325	79,635	89,372	362,872	337,766	266,574
Income from operations	22,205	41,363	46,034	47,010	38,554	28,150	30,660	37,778	156,612	135,142	58,387
Net income	$ 25,522	$ 29,769	$ 33,220	$ 33,786	$ 34,192	$ 29,117	$ 21,224	$ 31,245	$ 122,297	$ 115,778	$ 35,776
Net income per share:
Basic	$ 0.48	$ 0.56	$ 0.62	$ 0.63	$ 0.64	$ 0.55	$ 0.40	$ 0.58	$ 2.30	$ 2.17	$ 0.67
Diluted	0.48	0.56	0.62	0.63	0.64	0.55	0.40	0.58	2.28	2.16	0.67
Cash dividends paid per common share	$ 0.170	$ 0.170	$ 0.170	$ 0.165	$ 0.165	$ 0.165	$ 0.165	$ 0.160	$ 0.675	$ 0.655	$ 0.640

Schedule II - Valuation and 113

Schedule II - Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Valuation Allowance for Doubtful Accounts [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	$ 2,250	$ 1,924	$ 2,078
Additions Charged to Costs and Expenses	(255)	668	631
Additions Charged to Other Accounts	21	12	(62)
Deductions & Write-offs	(256)	(354)	(723)
Balance at End of Year	1,760	2,250	1,924
Valuation Allowance for Sales Returns [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	730	827	801
Additions Charged to Costs and Expenses	2,500	2,223	1,933
Additions Charged to Other Accounts	(3)		(36)
Deductions & Write-offs	(2,626)	(2,320)	(1,871)
Balance at End of Year	601	730	827
Valuation Allowance on Deferred Tax Asset [Member]
Valuation and Qualifying Accounts Disclosure [Line Items]
Balance at Beginning of Year	26,763	27,102	27,497
Additions Charged to Other Accounts	113
Deductions & Write-offs	(20,749)	(339)	(395)
Balance at End of Year	$ 6,127	$ 26,763	$ 27,102