Advanced Energy Industries (AEIS) 10-Q 6 May 19 2019 Q1 Quarterly report Financial data

Document and Enitity Informatio

Document and Enitity Information - shares	3 Months Ended
	Mar. 31, 2019	May 02, 2019
Document Entity Information [Abstract]
Entity Registrant Name	ADVANCED ENERGY INDUSTRIES INC
Entity Central Index Key	0000927003
Document Type	10-Q
Document Period End Date	Mar. 31, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Common Stock, Shares Outstanding		38,235,782

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
CURRENT ASSETS:
Cash and cash equivalents	$ 351,149	$ 349,301
Marketable securities	2,516	2,470
Accounts and other receivable, net of allowances of $2,851 and $1,748 respectively	102,405	100,442
Inventories	99,070	97,987
Income taxes receivable	1,945	2,220
Other current assets	11,309	10,173
Current assets from discontinued operations	4,872	5,855
Total current assets	573,266
Deposits and other assets	9,378	6,874
Property and equipment, net	31,058	31,269
Operating lease right-of-use assets	35,654	0
Goodwill	101,306	101,900
Intangible assets, net	52,858	54,910
Deferred income tax assets	47,513	47,099
Non-current assets from discontinued operations	5,917	5,984
TOTAL ASSETS	856,950	816,484
CURRENT LIABILITIES:
Accounts payable	44,028	39,646
Income taxes payable	12,584	13,258
Accrued payroll and employee benefits	16,528	21,775
Customer deposits and other	5,510	7,345
Customer deposits and other	7,298	0
Other accrued expenses	21,848	22,999
Current liabilities from discontinued operations	4,254	5,286
Total current liabilities	112,050
Operating Lease, Liability, Noncurrent	29,596	0
LONG-TERM LIABILITIES:
Deferred income tax liabilities	6,592	6,988
Uncertain tax positions	9,987	14,318
Long term deferred revenue	28,148	29,108
Other long-term liabilities	37,947	37,744
Non-current liabilities from discontinued operations	10,486	10,715
Total liabilities	234,806
STOCKHOLDERS' EQUITY:
Preferred stock, $0.001 par value, 1,000 shares authorized, none issued and outstanding	0	0
Common stock, $0.001 par value, 70,000 shares authorized; 38,716 and 39,604 issued and outstanding, respectively	38	38
Additional paid-in capital	98,910	97,418
Retained earnings	528,153	512,783
Advanced Energy stockholders’ equity	(5,477)	(3,449)
Advanced Energy stockholders’ equity	621,624	606,790
Noncontrolling interest	520	512
Total stockholders’ equity	622,144	607,302
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 856,950	$ 816,484

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets Parenthetical - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts receivable, allowances	$ 2,115	$ 1,856
Preferred stock, par value (in dollars per share)	$ 0.001	$ 0.001
Preferred stock, shares authorized (in shares)	1,000	1,000
Preferred stock, shares issued (in shares)	0	0
Preferred Stock, Shares Outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	70,000,000	70,000,000
Common stock, shares issued (in shares)	38,236,000	38,164,000
Common stock, shares outstanding (in shares)	38,236,000	38,164,000

Condensed Consolidated Statemen

Condensed Consolidated Statement of Operations Statement - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Sales:
Revenue from Contract with Customer, Excluding Assessed Tax	$ 140,743	$ 195,617
Cost of sales:
Total cost of sales	75,003	91,972
Gross profit	65,740	103,645
Operating expenses:
Research and development	21,289	17,637
Selling, general and administrative	29,014	28,648
Amortization of intangible assets	1,973	1,257
Restructuring Charges	1,673	0
Total operating expenses	53,949	47,542
Operating income	11,791	56,103
Other income (expense), net	743	26
Income from continuing operations, before income taxes	12,534	56,129
Provision (benefit) for income taxes	(2,853)	9,759
Income from continuing operations	15,387	46,370
Income (loss) from discontinued operations, net of income taxes	(9)	140
Net income	15,378	46,510
Income from continuing operations attributable to noncontrolling interest	8	31
Net income attributable to Advanced Energy Industries, Inc.	$ 15,370	$ 46,479
Basic weighted-average common shares outstanding	38,198	39,619
Diluted weighted-average common shares outstanding	38,426	39,995
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.40	$ 1.17
Income (Loss) from Continuing Operations, Per Diluted Share	0.40	1.16
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0	0
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0	0
Earnings Per Share, Basic	0.40	1.17
Earnings Per Share, Diluted	$ 0.40	$ 1.16
Product [Member]
Sales:
Revenue from Contract with Customer, Excluding Assessed Tax	$ 112,112	$ 171,209
Cost of sales:
Total cost of sales	60,801	79,806
Service [Member]
Sales:
Revenue from Contract with Customer, Excluding Assessed Tax	28,631	24,408
Cost of sales:
Total cost of sales	$ 14,202	$ 12,166

Condensed Consolidated Statem_2

Condensed Consolidated Statement of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 15,378	$ 46,510
Foreign currency translation	(1,975)	2,472
Minimum benefit retirement liability	53	168
Comprehensive income	13,350	48,814
Comprehensive income attributable to noncontrolling interest	8	31
Comprehensive income attributable to Advanced Energy Industries, Inc.	$ 13,342	$ 48,783

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 15,378	$ 46,510
CASH FLOWS FROM OPERATING ACTIVITIES:
Income (loss) from discontinued operations, net of income taxes	(9)	140
Income from continuing operations, net of income taxes	15,387	46,370
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	4,181	2,861
Stock-based compensation expense	3,199	4,494
Provision for deferred income taxes	(649)	0
Net loss on disposal of assets	(6)	(138)
Changes in operating assets and liabilities, net of assets acquired:
Accounts and other receivable, net	(2,416)	(17,457)
Inventories	(1,243)	(17,113)
Other current assets	(4,295)	364
Accounts payable	4,546	11,932
Other liabilities and accrued expenses	(7,165)	(2,346)
Income taxes	(4,696)	5,642
Net cash provided by operating activities from continuing operations	6,855	34,885
Net cash used in operating activities from discontinued operations	(1,409)	(1,784)
Net cash provided by operating activities	5,446	33,101
CASH FLOWS FROM INVESTING ACTIVITIES:
Acquisitions, net of cash acquired	0	(6,072)
Purchases of property and equipment	(2,436)	(3,923)
Net cash used in investing activities from continuing operations	(2,436)	(9,995)
Net cash used in investing activities from discontinued operations	0	0
Net cash used in investing activities	(2,436)	(9,995)
CASH FLOWS FROM FINANCING ACTIVITIES:
Purchase and retirement of common stock	0	12,750
Net payments related to stock-based award activities	(1,707)	(4,032)
Net cash used in financing activities from continuing operations	(1,707)	(16,782)
Net cash used in financing activities from discontinued operations	0	0
Net cash used in financing activities	(1,707)	(16,782)
EFFECT OF CURRENCY TRANSLATION ON CASH	(566)	167
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	737	6,491
CASH AND CASH EQUIVALENTS, beginning of period	354,552	415,037
CASH AND CASH EQUIVALENTS, end of period	355,289	421,528
Less cash and cash equivalents from discontinued operations	4,140	7,654
CASH AND CASH EQUIVALENTS FROM CONTINUING OPERATIONS, end of period	351,149	413,874
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	56	56
Cash paid for income taxes	2,371	3,404
Cash received for refunds of income taxes	61	95
Cash held in banks outside the United States	$ 174,980	$ 320,753

Condensed Consolidated Statem_3

Condensed Consolidated Statement of Stockholders Equity Statement - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Foreign Currency Translation	Minimum Benefit Retirement Liability	Retained Earnings	Non-controlling Interest
Adoption of new accounting standards	$ 19,706						$ 0
Beginning Balance at Dec. 31, 2017	520,641	$ 40	$ 184,843	$ 4,695	$ (2,162)	$ 333,225	0
Beginning Balance (in shares) at Dec. 31, 2017		39,604,000
Non-controlling interest from acquisition	431						431
Stock issued from equity plans (in shares)		113,000
Stock issued from equity plans	(4,127)	$ 0	(4,127)	0	0	0
Stock-based compensation	4,494	$ 0	4,494	0	0	0
Stock buyback (in shares)		181,000
Stock buyback	12,750	$ 0	12,750	0	0	0
Foreign currency translation	2,472	0	0	2,472	0	0
Minimum benefit retirement liability	168	0	0	0	168	0
Net income	46,479	0	0	0	0	46,479
Net Income, Non-controlling Interest	46,510						31
Total comprehensive income (loss)	48,783	$ 0	0	2,472	(168)	46,479
Total comprehensive income (loss), Non-controlling interest	48,814						31
Ending Balance (in shares) at Mar. 31, 2018		39,536,000
Ending Balance at Mar. 31, 2018	577,209	$ 40	172,460	7,167	(2,330)	399,410	462
Beginning Balance at Dec. 31, 2018	$ 607,302	$ 38	97,418	(590)	(2,859)	512,783	512
Beginning Balance (in shares) at Dec. 31, 2018	38,164,000	38,164,000
Stock issued from equity plans (in shares)		72,000
Stock issued from equity plans	$ (1,707)	$ 0	(1,707)	0	0	0
Stock-based compensation	3,199	0	3,199	0	0	0
Stock buyback	0
Foreign currency translation	(1,975)	0	0	(1,975)	0	0
Minimum benefit retirement liability	53	0	0	0	53	0
Net income	15,370	0	0	0	0	15,370
Net Income, Non-controlling Interest	15,378						8
Total comprehensive income (loss)	13,342	$ 0	0	(1,975)	(53)	15,370
Total comprehensive income (loss), Non-controlling interest	$ 13,350						8
Ending Balance (in shares) at Mar. 31, 2019	38,236,000	38,236,000
Ending Balance at Mar. 31, 2019	$ 622,144	$ 38	$ 98,910	$ (2,565)	$ (2,912)	$ 528,153	$ 520

Operations and Summary of Signi

Operations and Summary of Significant Accounting Policies and Estimates	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION Advanced Energy Industries, Inc., a Delaware corporation, and its wholly-owned subsidiaries ("we," "us," "our," "Advanced Energy," or the "Company") design, manufacture, sell and support precision power products that transform, refine, and modify the raw electrical power from the utility and convert it into various types of highly-controllable usable power that is predictable, repeatable and customizable. Our power solutions enable innovation in complex semiconductor and thin film plasma processes such as dry etch, strip, chemical and physical deposition, high and low voltage applications such as process control, analytical instrumentation and medical equipment, and in temperature-critical thermal applications such as material and chemical processing. We also supply related instrumentation products for advanced temperature measurement and control, electrostatic instrumentation products for test and measurement applications, and gas sensing and monitoring solutions for multiple industrial markets. Our network of global service support centers provides local repair and field service capability in key regions as well as provide upgrades and refurbishment services, and sales of used equipment to businesses that use our products. As of December 31, 2015, we discontinued our Inverter production, engineering, and sales product line. As such, all Inverter revenues, costs, assets and liabilities are reported in Discontinued Operations for all periods presented herein, and we currently report as a single unit. See Note 4. Discontinued Operations for more information. In the opinion of management, the accompanying Unaudited Condensed Consolidated Financial Statements contain all adjustments, consisting of normal, recurring adjustments, necessary to present fairly the financial position of the Company as of March 31, 2019 , and the results of our operations and cash flows for the three months ended March 31, 2019 and 2018 . The Unaudited Condensed Consolidated Financial Statements included herein have been prepared pursuant to the rules and regulations of the Securities and Exchange Commission ("SEC"). Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America ("U.S. GAAP") have been condensed or omitted pursuant to such rules and regulations. These Unaudited Condensed Consolidated Financial Statements should be read in conjunction with the audited Consolidated Financial Statements and Notes thereto contained in our Annual Report on Form 10-K for the fiscal year ended December 31, 2018 and other financial information filed with the SEC. Estimates and Assumptions The preparation of our Consolidated Financial Statements in conformity with U.S. GAAP requires us to make estimates, assumptions and judgments that affect the reported amounts of assets and liabilities, and disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. We believe that the significant estimates, assumptions, and judgments when accounting for items and matters such as allowances for doubtful accounts, excess and obsolete inventory, warranty reserves, right-of-use assets and related liabilities, acquisitions, asset valuations, asset life, depreciation, amortization, recoverability of assets, impairments, deferred revenue, stock option and restricted stock grants, taxes, and other provisions are reasonable, based upon information available at the time they are made. Actual results may differ from these estimates, making it possible that a change in these estimates could occur in the near term. Critical Accounting Policies Our accounting policies are described in our audited Consolidated Financial Statements and Notes contained in our Annual Report on Form 10-K for the year ended December 31, 2018 . See Note 16. Leases for the updated policies related to the implementation of ASU 2016-02, "Leases (Topic 842)." New Accounting Standards From time to time, the Financial Accounting Standards Board ("FASB") or other standards setting bodies issue new accounting pronouncements. Updates to the FASB Accounting Standards Codification ("ASC") are communicated through issuance of an Accounting Standards Update ("ASU"). Unless otherwise discussed, we believe that the impact of recently issued guidance, whether adopted or to be adopted in the future, is not expected to have a material impact on the Consolidated Financial Statements upon adoption. Recently issued accounting pronouncements not yet adopted In June 2016, The FASB issued ASU 2016-13, "Financial Instruments—Credit Losses (Topic 326)", Measurement of Credit Losses on Financial Instruments ("ASU 2016-13"). This ASU changes the methodology for measuring credit losses on financial instruments and the timing of when such losses are recorded. ASU 2016-13 is effective for fiscal years, and interim periods within those years, beginning after December 15, 2019. Early adoption is permitted for fiscal years, and interim periods within those years, beginning after December 15, 2018. We are currently assessing the impact ASU 2016-13 will have on our Consolidated Financial Statements. In August 2018, the FASB issued ASU 2018-13, "Fair Value Measurement (Topic 820)" ("ASU 2018-13"). ASU 2018-13 modifies the disclosure requirements on fair value measurements in Topic 820, Fair Value Measurement, based on the concepts in the Concepts Statement, including the consideration of costs and benefits. ASU 2018-13 is effective for fiscal years ending after December 15, 2019 and shall be applied to all periods presented on a retrospective basis. Early adoption is permitted. We are currently assessing and do not believe ASU 2018-13 will have a significant impact on our fair value measurements disclosure requirements. In August 2018, the FASB issued ASU 2018-14, "Compensation—Retirement Benefits—Defined Benefit Plans—General (Subtopic 715-20)" ("ASU 2018-14"). ASU 2018-14 eliminates requirements for certain disclosures and requires additional disclosures under defined benefit pension plans and other post-retirement plans. ASU 2018-14 is effective for fiscal years ending after December 15, 2020 and shall be applied to all periods presented on a retrospective basis. Early adoption is permitted. We are currently assessing and do not believe ASU 2018-14 will have a significant impact on our defined benefit plan disclosure requirements. Recently adopted accounting pronouncements In February 2018, the FASB issued ASU 2018-02, "Income Statement—Reporting Comprehensive Income" to give companies the option to reclassify the income tax effects on items within accumulated other comprehensive income resulting from the Tax Act to retained earnings. ASU 2018-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within those years. We adopted ASU 2018-02 during the first quarter of fiscal year 2019 which did not have an impact on our Consolidated Financial Statements. In June 2018, the FASB issued ASU 2018-07, "Compensation-Stock Compensation (Topic 718)", Improvements to Non-employee Share-based Payments (“ASU 2018-07”). This ASU expands the scope of Topic 718 to include share-based payment transactions for acquiring goods and services from non-employees. ASU 2018-07 is effective for fiscal years beginning after December 15, 2018. The new guidance is required to be applied retrospectively with the cumulative effect recognized at the date of initial application. We adopted ASU 2018-07 during the first quarter of fiscal year 2019 which did not have an impact on our Consolidated Financial Statements. In August 2017, the FASB issued ASU 2017-12, "Derivatives and Hedging (Topic 815)", Targeted Improvements to Accounting for Hedging Activities ("ASU 2017-12"). This ASU simplifies certain aspects of hedge accounting and results in a more accurate portrayal of the economics of an entity’s risk management activities in its financial statements. ASU 2017-12 is effective for fiscal years beginning after December 15, 2018, and the interim periods within those fiscal years. We adopted ASU 2017-12 during the first quarter of fiscal year 2019 using the modified retrospective basis. The adoption of the provisions of ASU 2017-12 did not materially impact the company's Consolidated Balance Sheet or Statement of Operations. In February 2016, the FASB issued ASU 2016-02, "Leases (Topic 842)," to increase transparency and comparability among organizations by recognizing lease right-of-use assets and lease liabilities on the balance sheet and disclosing key information about leasing arrangements. ASU 2016-02 is effective for fiscal years beginning after December 15, 2018, including interim periods within the year of adoption. We adopted ASU 2016-02 using the modified retrospective approach and recorded $38.2 million of operating lease right-of-use assets and $38.4 million of operating lease liabilities as the cumulative-effect in the first quarter of fiscal year 2019. The adoption of ASU 2016-02 did not materially impact the company's Consolidated Statement of Operations or Consolidated Statement of Cash Flows for the period ended March 31, 2019 .

Business Acquisition (Notes)

Business Acquisition (Notes)	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
BUSINESS ACQUISITION	BUSINESS ACQUISITIONS LumaSense Technologies Holdings, Inc. In September 2018, Advanced Energy acquired LumaSense Technologies Holdings, Inc. ("LumaSense"), a privately held company with primary operations in Santa Clara, California, Frankfurt, Germany, and Ballerup, Denmark for a net purchase price of $84.7 million in cash. The components of the fair value of the total consideration transferred for our acquisition is as follows: LumaSense Cash paid for acquisition $ 94,946 Cash acquired (10,262 ) Total fair value of consideration transferred $ 84,684 The following table summarizes estimated fair values of the assets acquired and liabilities assumed from our acquisition: LumaSense Accounts and other receivable, net $ 7,167 Inventories 9,372 Property and equipment 1,353 Goodwill 48,032 Intangible assets 26,000 Deferred income tax assets 8,116 Other assets 5,126 Total assets acquired 105,166 Accounts payable 5,734 Deferred income tax liabilities 7,984 Other liabilities 6,764 Total liabilities assumed 20,482 Total fair value of net assets acquired $ 84,684 A summary of the intangible assets acquired, amortization method and estimated useful lives are as follows: LumaSense Amortization Method Useful Life Technology $ 20,000 Straight-line 10 Customer relationships 6,000 Straight-line 10 Total $ 26,000 Goodwill and intangible assets are recorded in the functional currency of the entity and are subject to changes due to translation at each balance sheet date. The goodwill represents expected operating synergies from combining operations with the acquired companies and the estimated value associated with the enhancements to our comprehensive product lines. Advanced Energy is in the process of finalizing the assessment of fair value for the assets acquired and liabilities assumed related to the LumaSense acquisition. Pro forma results for Advanced Energy Inc. giving effect to the LumaSense Technologies Holdings, Inc. Transaction The following unaudited pro forma financial information presents the combined results of operations of Advanced Energy Inc. and LumaSense as if the acquisitions had been completed as of the beginning of the prior fiscal year, or January 1, 2018. The unaudited pro forma financial information is presented for informational purposes and is not indicative of the results of operations that would have been achieved if the acquisitions had taken place on January 1, 2018, nor are they indicative of future results. The unaudited pro forma financial information for the three months ended March 31, 2019 includes Advanced Energy's results, including the post-acquisition results of LumaSense, since September 1, 2018. The unaudited pro forma financial information for the three months ended March 31, 2018 combines Advanced Energy's results with the pre-acquisition results of LumaSense for that period. The unaudited pro forma results for the three months ended March 31, 2019 and 2018 are as follows: March 31, 2019 March 31, 2018 As reported Pro forma As reported Pro forma Total sales 140,743 140,743 195,617 210,465 Net income attributable to Advanced Energy Industries, Inc. 15,370 15,491 46,479 46,310 Earnings per share: Basic earnings per share $ 0.40 $ 0.41 $ 1.17 $ 1.17 Diluted earnings per share $ 0.40 $ 0.40 $ 1.16 $ 1.16 The unaudited pro forma results for all periods presented include adjustments made to account for certain costs and transactions that would have been incurred had the acquisitions been completed as of January 1, 2018. These adjustments including amortization charges for acquired intangible assets, adjustments for acquisition transaction costs and amortization of purchased gross profit. These adjustments are net of any applicable tax impact and were included to arrive at the pro forma results above. LumaSense’s operating results have been included in the Advanced Energy's operating results for the periods subsequent to the completion of the acquisition on September 1, 2018. LumaSense contributed total sales of $12.0 million and a net income of $0.9 million for the three months ended March 31, 2019 .

Revenue (Notes)

Revenue (Notes)	3 Months Ended
	Mar. 31, 2019
Revenue [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUE Revenue Recognition We recognize revenue when we have satisfied our performance obligations which typically occurs when control of the products or services have been transferred to our customers. The transaction price is based upon the standalone selling price. In most transactions, we have no obligations to our customers after the date products are shipped, other than pursuant to warranty obligations. Shipping and handling fees billed to customers, if any, are recognized as revenue. The related shipping and handling costs are recognized in cost of sales. Support services include warranty and non-warranty repair services, upgrades, and refurbishments on the products we sell. Repairs that are covered under our standard warranty do not generate revenue. Practical Expedients We expense incremental costs of obtaining contracts when the amortization period of the costs is less than 1 year. These costs are included in selling, general, and administrative expenses. Nature of goods and services Products Advanced Energy provides highly-engineered, mission-critical, precision power conversion, measurement and control solutions to our global customers. We design, manufacture, sell and support precision power products that transform electrical power into various usable forms. Our power conversion products refine, modify and control the raw electrical power from a utility and convert it into power that is predictable, repeatable and customizable. Our products enable thin film manufacturing processes such as plasma enhanced chemical and physical deposition and etch for various semiconductor and industrial products, industrial thermal applications for material and chemical processes, and specialty power for critical industrial technology applications. We also supply thermal instrumentation products for advanced temperature measurement and control in these markets. Our products are designed to enable new process technologies, improve productivity, and lower the cost of ownership for our customers. We also provide repair and maintenance services for all our products. We principally serve original equipment manufacturers ("OEM") and end customers in the semiconductor, flat panel display, high voltage, solar panel, and other industrial capital equipment markets. Our products are used in diverse markets, applications, and processes including the manufacture of capital equipment for semiconductor device manufacturing, thin film applications for thin film renewables and architectural glass, and for other thin film applications including flat panel displays, and industrial coatings. Services Our global support services group offers warranty and after-market repair services in the regions in which we operate, providing us with preventive maintenance opportunities. Our customers continue to pursue low cost of ownership of their capital equipment and are increasingly sensitive to the costs of system downtime. They expect that suppliers offer comprehensive local repair service and customer support. To meet these market requirements, we maintain a worldwide support organization comprising of both direct and indirect activities, through partnership with local distributors, primarily in the United States ("U.S."), the People’s Republic of China ("PRC"), Japan, South Korea, Taiwan, Germany, Singapore and United Kingdom. As part of our ongoing service business, we satisfy our service obligations under preventative maintenance contracts and extended warranties which had previously been offered on our discontinued inverter products. Any up-front fees received for extended warranties or maintenance plans are deferred. Revenue under these arrangements is recognized ratably over the underlying terms as we do not have historical information which would allow us to project the estimated service usage pattern at this time. We have deferred revenue related to our extended warranties and service contracts totaling $32.5 million as of March 31, 2019 and $33.4 million as of December 31, 2018 . We are expected to recognize between $0.1 million and $3.5 million per year through 2034. Disaggregation of Revenue The following table presents our net sales by product line: Three Months Ended March 31, 2019 2018 Semiconductor capital market $ 67,514 $ 136,010 Industrial technology capital market 44,598 35,199 Global support 28,631 24,408 Total $ 140,743 $ 195,617 The following table presents our net sales by geographic region: Three Months Ended March 31, 2019 2018 Sales to external customers: United States $ 57,875 41.1 % $ 107,267 54.8 % Other North American countries 631 0.4 630 0.3 North America 58,506 41.5 107,897 55.1 Republic of Korea 13,800 9.8 24,893 12.7 People's Republic of China 15,474 11.0 11,870 6.1 Taiwan 11,621 8.3 7,540 3.9 Singapore 6,105 4.3 13,632 7.0 Other Asian countries 11,435 8.1 8,229 4.2 Asia 58,435 41.5 66,164 33.9 Germany 7,573 5.4 8,261 4.2 Other European countries 15,853 11.3 13,188 6.7 Europe 23,426 16.7 21,449 10.9 Other Countries 376 0.3 107 0.1 Total $ 140,743 100.0 % $ 195,617 100.0 %

Discontinued Operations (Notes)

Discontinued Operations (Notes)	3 Months Ended
	Mar. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]	DISCONTINUED OPERATIONS In December 2015, we completed the wind down of engineering, manufacturing and sales of our solar inverter product line (the "inverter business"). Accordingly, the results of our inverter business have been reflected as " Income (loss) from discontinued operations, net of income taxes " on our Consolidated Statements of Operations for all periods presented herein. The effect of our sales of extended inverter warranties to our customers continues to be reflected in deferred revenue in our Consolidated Balance Sheets. Deferred revenue for extended inverter warranties and the associated costs of warranty service will be reflected in Sales and Cost of goods sold, respectively, from continuing operations in future periods in our Consolidated Statement of Operations, as the deferred revenue, is earned and the associated services are rendered. Extended warranties related to the inverter product line are no longer offered. The significant items included in " Income (loss) from discontinued operations, net of income taxes " are as follows: Three Months Ended March 31, 2019 2018 Sales $ — $ — Cost of sales — 112 Total operating expense (benefit) — (61 ) Operating income (loss) from discontinued operations — (51 ) Other income (expense) (4 ) 124 Income (loss) from discontinued operations before income taxes (4 ) 73 Provision (benefit) for income taxes 5 (67 ) Income (loss) from discontinued operations, net of income taxes $ (9 ) $ 140 Assets and Liabilities of discontinued operations within the Condensed Consolidated Balance Sheets are comprised of the following: March 31, December 31, 2019 2018 Cash and cash equivalents $ 4,140 $ 5,251 Other current assets 430 406 Inventories 302 198 Current assets of discontinued operations $ 4,872 $ 5,855 Other assets $ — $ 67 Deferred income tax assets 5,917 5,917 Non-current assets of discontinued operations $ 5,917 $ 5,984 Accounts payable and other accrued expenses $ 349 $ 350 Accrued warranty 3,905 4,936 Current liabilities of discontinued operations $ 4,254 $ 5,286 Accrued warranty $ 10,344 $ 10,429 Other liabilities 142 286 Non-current liabilities of discontinued operations $ 10,486 $ 10,715

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXES The following table sets out the tax expense and the effective tax rate for our income from continuing operations: Three Months Ended March 31, 2019 2018 Income from continuing operations, before income taxes $ 12,534 $ 56,129 Provision (benefit) for income taxes (2,853 ) 9,759 Effective tax rate (22.8 )% 17.4 % Our effective tax rates differ from the U.S. federal statutory rate of 21% for the three months ended March 31, 2019 and 2018 , respectively, primarily due to the benefit of earnings in foreign jurisdictions which are subject to lower tax rates, partially offset by additional GILTI tax in the U.S. The effective tax rate for the first quarter of 2019 was lower than the same period in 2018 primarily due to the release of liabilities for uncertain tax positions in 2019 based on the completion of additional procedures during the quarter to support a change in facts with respect to a specific prior period position.

Earnings Per Share

Earnings Per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
EARNINGS PER SHARE	EARNINGS 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 our diluted EPS is similar to the computation of our basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding (using the if-converted and treasury stock methods), if our outstanding stock options and restricted stock units had been converted to common shares, and if such assumed conversion is dilutive. The following is a reconciliation of the weighted-average shares outstanding used in the calculation of basic and diluted EPS for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 Income from continuing operations $ 15,387 $ 46,370 Income from continuing operations attributable to noncontrolling interest 8 31 Income from continuing operations attributable to Advanced Energy Industries, Inc. $ 15,379 $ 46,339 Basic weighted-average common shares outstanding 38,198 39,619 Assumed exercise of dilutive stock options and restricted stock units 228 376 Diluted weighted-average common shares outstanding 38,426 39,995 Continuing operations: Basic earnings per share $ 0.40 $ 1.17 Diluted earnings per share $ 0.40 $ 1.16 The following restricted stock units were excluded in the computation of diluted earnings per share because they were anti-dilutive: Three Months Ended March 31, 2019 2018 Restricted stock units 119 2 Stock Buyback In September 2015, our Board of Directors authorized a program to repurchase up to $150.0 million of our stock over a thirty-month period. In November 2017, our Board of Directors approved an extension of the share repurchase program to December 2019 from its original maturity of March 2018. In May 2018 our Board of Directors approved a $50 million increase in its authorization to repurchase shares of Company common stock under this same program. As of March 31, 2019 , we had $24.9 million remaining for the future repurchase of shares of our common stock. In order to execute the repurchase of shares of our common stock, the company periodically enters into stock repurchase agreements. During the three months ended March 31, 2019 and 2018 , the company has repurchased the following shares of common stock: Three Months Ended March 31, 2019 2018 Amount paid to repurchase shares $ — $ 12,750 Number of shares repurchased — 181 Average repurchase price per share $ — $ 70.47 There were no shares repurchased from related parties. All shares repurchased were recognized as a reduction to Additional paid-in capital. Repurchased shares were retired and assumed the status of authorized and unissued shares.

Marketable Securities

Marketable Securities	3 Months Ended
	Mar. 31, 2019
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	MARKETABLE SECURITIES AND ASSETS MEASURED AT FAIR VALUE Our investments with original maturities of more than three months at the time of purchase and that are intended to be held for no more than 12 months, are considered marketable securities available for sale. Our marketable securities consist of certificates of deposit as follows: March 31, 2019 December 31, 2018 Cost Fair Value Cost Fair Value Total marketable securities $ 2,511 $ 2,516 $ 2,463 $ 2,470 The maturities of our marketable securities available for sale as of March 31, 2019 are as follows: Earliest Latest Certificates of deposit 4/10/2019 to 10/17/2019 The value and liquidity of the marketable securities we hold are affected by market conditions, as well as the ability of the issuers of such securities to make principal and interest payments when due, and the functioning of the markets in which these securities are traded. As of March 31, 2019 , we do not believe any of the underlying issuers of our marketable securities are at risk of default. The following tables present information about our marketable securities measured at fair value, on a recurring basis, as of March 31, 2019 and December 31, 2018 . The tables indicate the fair value hierarchy of the valuation techniques utilized to determine fair value. We did not have any financial liabilities measured at fair value, on a recurring basis, as of March 31, 2019 and December 31, 2018 . March 31, 2019 Level 1 Level 2 Level 3 Total Total marketable securities $ — $ 2,516 $ — $ 2,516 December 31, 2018 Level 1 Level 2 Level 3 Total Total marketable securities $ — $ 2,470 $ — $ 2,470 There were no transfers in or out of Level 1, 2, or 3 fair value measurements during the three months ended March 31, 2019 .

Derivative Financial Instrument

Derivative Financial Instruments	3 Months Ended
	Mar. 31, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVE FINANCIAL INSTRUMENTS	DERIVATIVE FINANCIAL INSTRUMENTS We are impacted by changes in foreign currency exchange rates. We may manage these risks through the use of derivative financial instruments, primarily forward contracts with banks for one-month periods. These forward contracts manage the exchange rate risk associated with intercompany debt denominated in nonfunctional currencies. These derivative instruments are not designated as hedges; however, they do offset the fluctuations of our intercompany debt due to foreign exchange rate changes. We did not enter into any new foreign currency exchange forward contracts during the three months ended March 31, 2019 and 2018 . We did not have any currency exchange rate contracts outstanding as of March 31, 2019 and 2018 . During the three months ended March 31, 2019 and 2018 the gains and losses recorded related to the foreign currency exchange contracts are as follows: Three Months Ended March 31, 2019 2018 Foreign currency loss from foreign currency exchange contracts $ — $ (750 ) These gains and losses were offset by corresponding gains and losses on the revaluation of the underlying intercompany debt and both are included as a component of Other income, net , in our Unaudited Condensed Consolidated Statements of Operations.

Accounts and Other Receivables

Accounts and Other Receivables	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Accounts and Other Receivables	ACCOUNTS AND OTHER RECEIVABLE Accounts and other receivable are recorded at net realizable value. Components of accounts and other receivable, net of reserves, are as follows: March 31, December 31, 2019 2018 Amounts billed, net $ 87,607 $ 80,709 Unbilled receivables 14,798 19,733 Total receivables, net $ 102,405 $ 100,442 Amounts billed, net consist of amounts that have been invoiced to our customers in accordance with our terms and conditions and are shown net of an allowance for doubtful accounts. Unbilled receivables consist of amounts where we have satisfied our contractual obligations related to inventory stocking contracts with customers. Such amounts typically become billable to the customer upon their consumption of the inventory managed under the stocking contracts. We anticipate that substantially all unbilled receivables will be invoiced and collected over the next twelve months.

Inventories

Inventories	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
INVENTORIES	INVENTORIES Our inventories are valued at the lower of cost or net realizable value and computed on a first-in, first-out (FIFO) basis. Components of inventories are as follows: March 31, December 31, 2019 2018 Parts and raw materials $ 75,870 $ 76,647 Work in process 9,286 6,644 Finished goods 13,914 14,696 Total $ 99,070 $ 97,987

Property and Equipment

Property and Equipment	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
PROPERTY AND EQUIPMENT	Property and equipment, net is comprised of the following: March 31, December 31, 2019 2018 Buildings and land $ 1,719 $ 1,737 Machinery and equipment 42,985 41,330 Computer and communication equipment 24,721 24,051 Furniture and fixtures 3,189 3,203 Vehicles 282 282 Leasehold improvements 20,487 20,593 Construction in process 1,113 867 94,496 92,063 Less: Accumulated depreciation (63,438 ) (60,794 ) Property and equipment, net $ 31,058 $ 31,269 Depreciation expense recorded in continuing operations and included in selling, general and administrative expense is as follows: Three Months Ended March 31, 2019 2018 Depreciation expense $ 2,208 $ 1,604

Goodwill

Goodwill	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL	GOODWILL The following summarizes the changes in goodwill during the three months ended March 31, 2019 : Beginning Balance Effect of Changes in Exchange Rates Ending Balance March 31, 2019 $ 101,900 $ (594 ) $ 101,306

Intangible Assets

Intangible Assets	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
INTANGIBLE ASSETS	INTANGIBLE ASSETS Intangible assets consisted of the following as of March 31, 2019 and December 31, 2018 : March 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Technology $ 39,730 $ (8,967 ) $ 30,763 Customer relationships 35,416 (14,241 ) 21,175 Trademarks and other 2,518 (1,598 ) 920 Total $ 77,664 $ (24,806 ) $ 52,858 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Technology $ 39,879 $ (7,927 ) $ 31,952 Customer relationships 35,509 (13,484 ) 22,025 Trademarks and other 2,501 (1,568 ) 933 Total $ 77,889 $ (22,979 ) $ 54,910 Amortization expense related to intangible assets is as follows: Three Months Ended March 31, 2019 2018 Amortization expense $ 1,973 $ 1,257 Estimated amortization expense related to intangibles is as follows: Year Ending December 31, 2019 (remaining) $ 5,612 2020 6,842 2021 6,743 2022 6,486 2023 6,468 Thereafter 20,707 Total $ 52,858

Restructuring Costs

Restructuring Costs	3 Months Ended
	Mar. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring Costs	RESTRUCTURING COSTS During 2018, we committed to a restructuring plan to optimize our manufacturing footprint and to improve our operating efficiencies and synergies related to our recent acquisitions. The table below summarizes the restructuring charges: Three Months Ended March 31, 2019 Cumulative Cost Through March 31, 2019 Severance and related charges $ 153 $ 4,392 Facility relocation and closure charges 1,520 1,520 Total restructuring charges $ 1,673 $ 5,912 The following table summarizes our restructuring liabilities at March 31, 2019 : Balance at December 31, 2018 Cost Incurred and Charged to Expense Cost Paid or Otherwise Settled Effect of Changes in Exchange Rates Balance at March 31, 2019 Total restructuring liabilities $ 3,806 $ 1,673 $ (2,360 ) $ (11 ) $ 3,108 As of December 31, 2018 and March 31, 2019 the accrued restructuring liabilities related primarily to severance and related charges.

Warranties

Warranties	3 Months Ended
	Mar. 31, 2019
Product Warranties Disclosures [Abstract]
WARRANTIES	WARRANTIES Provisions of our sales agreements include customary product warranties, ranging from 12 months to 24 months following installation. The estimated cost of our warranty obligation is recorded when revenue is recognized and is based upon our historical experience by product, configuration and geographic region. Our estimated warranty obligation is included in Other accrued expenses in our Consolidated Balance Sheets. Changes in our product warranty obligation are as follows: Three Months Ended March 31, 2019 2018 Balances at beginning of period $ 2,084 $ 2,312 Warranty liabilities acquired — 92 Increases to accruals 519 178 Warranty expenditures (345 ) (506 ) Effect of changes in exchange rates 6 8 Balances at end of period $ 2,264 $ 2,084

Leases

Leases	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Leases	LEASES We lease manufacturing and office space under non-cancelable operating leases. Some of these leases contain provisions for landlord funded leasehold improvements which are recorded as right of use assets with related liabilities. Additionally, several existing operating leases had deferred rent balances under ASC 840 which resulted in adjusted right of use asset balances recorded upon adoption of ASC 842. Most leases include one or more options to renew. We regularly evaluate the renewal options and when they are reasonably certain of exercise, we include the renewal period in our lease terms, along with the right-of-use assets ("ROU") and lease liabilities. In many cases, we have lease terms that are less than one year and therefore, we have elected the practical expedient to exclude these short-term leases from our ROU assets and lease liabilities. Our leases do not provide an implicit rate. Accordingly, we use our incremental borrowing rate based on the information available at the lease commencement date in determining the present value of the lease payments. We have a centrally managed treasury function; therefore, based on the applicable lease terms and the current economic environment, we apply a portfolio approach for determining the incremental borrowing rate. New leases are negotiated and executed to meet business objectives on an on-going basis. During the second fiscal quarter of 2019, we expect to record additional right of use assets and related liabilities for facilities in Metzingen, Germany and Denver, Colorado, USA. The lease in Metzingen commences on April 1, 2019 with a term of 3 years ; the right of use asset and liability recorded at commencement will be $1.2 million . The lease in Denver, Colorado is expected to commence in June 2019 with a term of 10 years ; the right of use asset and liability recorded at commencement will be $15.7 million . Maturities of our lease liabilities for all operating leases at March 31, 2019 are as follows: Year Ending December 31, 2019 (remaining) $ 6,003 2020 6,243 2021 5,937 2022 4,273 2023 2,974 Thereafter 17,928 Total lease payments $ 43,358 Less: Interest (6,464 ) Present value of lease liabilities $ 36,894 The weighted average remaining lease term and discount rate for all of our operating leases were as follows as of March 31, 2019 : Weighted Average Remaining Lease Term Weighted Average Discount Rate Operating Leases 8.35 years 3.75 % Supplemental cash flow information related to our operating leases was as follows for the period ended March 31, 2019 : Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflow from operating leases $ 2,891

Pension Liability (Notes)

Pension Liability (Notes)	3 Months Ended
	Mar. 31, 2019
Retirement Benefits [Abstract]
Pension Liability	PENSION LIABILITY In connection with the acquisition of HiTek Power Group and LumaSense, we acquired the HiTek Power Limited Pension Scheme (the "HiTek Plan") and the LumaSense Technologies GmbH pension obligation (the "LumaSense Plan"), respectively. These plans are both closed to new participants. In order to measure the expense and related benefit obligation, various assumptions are made including discount rates used to value the obligation, expected return on plan assets used to fund these expenses and estimated future inflation rates. These assumptions are based on historical experience as well as facts and circumstances. An actuarial analysis is used to measure the expense and liability associated with pension benefits. We are committed to make annual fixed payments of $0.9 million into the HiTek Plan through April 30, 2024, and then $1.8 million from May 1, 2024 through November 30, 2033. We are not currently committed to future payments to the LumaSense Plan. The net pension liability is included in Other long-term liabilities in our balance sheet as follows: March 31, December 31, 2019 2018 Pension liability $ 19,874 $ 19,266 The following table sets forth the components of net periodic pension cost for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 Interest cost $ 199 $ 218 Expected return on plan assets (170 ) (161 ) Amortization of actuarial gains and losses 118 136 Net periodic pension cost $ 147 $ 193

Stock-Based Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
STOCK-BASED COMPENSATION	STOCK-BASED COMPENSATION On May 4, 2017, the shareholders approved the Company's 2017 Omnibus Incentive Plan ("the 2017 Plan") and all shares that were then available for issuance under the 2008 Omnibus Incentive Plan are now available for issuance under the 2017 Plan. The 2017 Plan provides for the grant of stock options, stock appreciation rights, restricted stock, stock units (including deferred stock units), unrestricted stock, and dividend equivalent rights. Any of the awards issued under the 2017 Plan may be issued as performance-based awards to align compensation awards to the attainment of annual or long-term performance goals. As of March 31, 2019 , there were 3.1 million shares reserved and 2.3 million shares available for grant under the 2017 Plan. Restricted stock units ("RSU’s") are generally granted with a grant date fair value equal to the market price of our stock at the date of grant and with generally a three or four-year vesting schedule or performance-based vesting as determined at the time of grant. Stock option awards are generally granted with an exercise price equal to the market price of our stock at the date of grant and with either a three or four-year vesting schedule or performance-based vesting as determined at the time of grant. Stock option awards generally have a term of 10 years. We recognize stock-based compensation expense based on the fair value of the awards issued and the functional area of the employee receiving the award. Stock-based compensation for the three months ended March 31, 2019 and 2018 was as follows: Three Months Ended March 31, 2019 2018 Stock-based compensation expense $ 3,199 $ 4,494 Changes in the outstanding RSU awards during the three months ended March 31, 2019 were as follows: Three Months Ended March 31, 2019 Number of RSUs Weighted-Average Grant Date Fair Value RSUs outstanding at beginning of period 352 $ 58.17 RSUs granted 331 $ 51.94 RSUs vested (96 ) $ 48.14 RSUs forfeited (10 ) $ 32.19 RSUs outstanding at end of period 577 $ 56.73 Changes in the outstanding stock option awards during the three months ended March 31, 2019 were as follows: Three Months Ended March 31, 2019 Number of Options Weighted-Average Exercise Price per Share Options outstanding at beginning of period 230 $ 20.73 Options exercised (9 ) $ 10.50 Options expired (1 ) $ 7.69 Options outstanding at end of period 220 $ 21.21 Changes in the outstanding RSU awards during the three months ended March 31, 2019 were as follows: Three Months Ended March 31, 2019 Number of RSUs Weighted-Average Grant Date Fair Value RSUs outstanding at beginning of period 352 $ 58.17 RSUs granted 331 $ 51.94 RSUs vested (96 ) $ 48.14 RSUs forfeited (10 ) $ 32.19 RSUs outstanding at end of period 577 $ 56.73

Commitments and Contingencies

Commitments and Contingencies	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES We have firm purchase commitments and agreements with various suppliers to ensure the availability of components. The obligation as of March 31, 2019 is approximately $99.4 million . Our policy with respect to all purchase commitments is to record losses, if any, when they are probable and reasonably estimable. We continuously monitor these commitments for exposure to potential losses and will record a provision for losses when it is deemed necessary. We are involved in disputes and legal actions arising in the normal course of our business. There have been no material developments in legal proceedings in which we are involved during the three months ended March 31, 2019 .

Related Party Transactions

Related Party Transactions	3 Months Ended
	Mar. 31, 2019
Related Party Transactions [Abstract]
RELATED PARTY TRANSACTIONS	RELATED PARTY TRANSACTIONS Members of our Board of Directors hold various executive positions and serve as directors at other companies, including companies that are our customers. During the three months ended March 31, 2019 , we engaged in the following transactions with companies related to members of our Board of Directors, as described below: Three Months Ended March 31, 2019 2018 Sales to related parties $ 352 $ 73 Number of related party customers 1 1 Our accounts receivable balance from related party customers with outstanding balances as of March 31, 2019 and December 31, 2018 is as follows: March 31, December 31, 2019 2018 Accounts receivable from related parties $ 154 $ 109 Number of related party customers 1 1

Geographic and Customer Informa

Geographic and Customer Information Geographic and Customer Information (Notes)	3 Months Ended
	Mar. 31, 2019
Segment Reporting Information [Line Items]
Segment Reporting Disclosure [Text Block]	SIGNIFICANT CUSTOMER INFORMATION The following table summarizes sales, and percentages of sales, by customers that individually accounted for 10% or more of our sales for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 % of Total Sales 2018 % of Total Sales Applied Materials, Inc. $ 36,290 25.8 % $ 69,872 35.7 % LAM Research 19,667 14.0 % 39,726 20.3 % The following table summarizes the accounts receivable balances, and percentages of the total accounts receivable, for customers that individually accounted for 10% or more of accounts receivable as of March 31, 2019 and December 31, 2018 : March 31, December 31, 2019 2018 Applied Materials, Inc. $ 27,150 26.5 % $ 34,301 34.2 % LAM Research 11,941 11.7 % 12,181 12.1 % Our sales to Applied Materials, Inc. and LAM Research include precision power products used in semiconductor processing and solar and flat panel display. No other customer accounted for 10% or more of our sales or accounts receivable balances during these periods.

Credit Facility

Credit Facility	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
CREDIT FACILITY	CREDIT FACILITY The Company is party to a Loan Agreement, as amended (the "Loan Agreement") with Bank of America N.A. ("BA") which provides a revolving line of credit of up to $150.0 million subject to certain funding conditions. The Loan Agreement expires on July 28, 2022 . Interest on amounts drawn shall be paid quarterly based upon the LIBOR Daily Floating Rate then in effect, plus between one and one-quarter ( 1.25% ) and one and three-quarters ( 1.75% ) percentage points depending on the Funded Debt to EBITDA ratio. As of March 31, 2019 , the interest rate was 3.75% . The Loan Agreement also requires the Company to pay the lender on a quarterly basis an unused commitment fee based on credit availability. The obligations under the Loan Agreement are unsecured until the Funded Debt to EBITDA ratio exceeds 2.0 to 1.0, at which time the Company and certain affiliates’ tangible and intangible personal property will be subject to a first priority, perfected lien and security interest in favor of BA pursuant to a Security Agreement. As of March 31, 2019 , the Company is in compliance with all covenants required under the Loan Agreement. At March 31, 2019 our credit availability under the Loan Agreement was $150.0 million . Interest expense related to unused line of credit fees was as follows: Three Months Ended March 31, 2019 2018 Unused line of credit fees $ 56 $ 56

Revenue (Policies)

Revenue (Policies)	3 Months Ended
	Mar. 31, 2019
Revenue [Abstract]
Revenue Recognition, Policy [Policy Text Block]

Commitments and Contingencies C

Commitments and Contingencies Commitments and Contingencies (Policies)	3 Months Ended
	Mar. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Our policy with respect to all purchase commitments is to record losses, if any, when they are probable and reasonably estimable.

Basis of Presentation - (Tables

Basis of Presentation - (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

Business Acquisition (Tables)

Business Acquisition (Tables)	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Schedule of components of the fair value of total consideration transferred	The components of the fair value of the total consideration transferred for our acquisition is as follows: LumaSense Cash paid for acquisition $ 94,946 Cash acquired (10,262 ) Total fair value of consideration transferred $ 84,684
Schedule of estimated fair value of assets acquired and liabilities assumed	The following table summarizes estimated fair values of the assets acquired and liabilities assumed from our acquisition: LumaSense Accounts and other receivable, net $ 7,167 Inventories 9,372 Property and equipment 1,353 Goodwill 48,032 Intangible assets 26,000 Deferred income tax assets 8,116 Other assets 5,126 Total assets acquired 105,166 Accounts payable 5,734 Deferred income tax liabilities 7,984 Other liabilities 6,764 Total liabilities assumed 20,482 Total fair value of net assets acquired $ 84,684
Summary of intangible assets	A summary of the intangible assets acquired, amortization method and estimated useful lives are as follows: LumaSense Amortization Method Useful Life Technology $ 20,000 Straight-line 10 Customer relationships 6,000 Straight-line 10 Total $ 26,000
Unaudited pro forma information	The unaudited pro forma financial information for the three months ended March 31, 2019 includes

Revenue Revenue by Product Line

Revenue Revenue by Product Line (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table presents our net sales by extended warranty and service contracts recognized over time and our product and service revenue recognized at a point in time: Three Months Ended March 31, 2019 2018 Product and service revenue recognized at point in time $ 139,840 $ 194,683 Extended warranty and service contracts recognized over time 903 934 Total $ 140,743 $ 195,617 The following table presents our net sales by geographic region: Three Months Ended March 31, 2019 2018 Sales to external customers: United States $ 57,875 41.1 % $ 107,267 54.8 % Other North American countries 631 0.4 630 0.3 North America 58,506 41.5 107,897 55.1 Republic of Korea 13,800 9.8 24,893 12.7 People's Republic of China 15,474 11.0 11,870 6.1 Taiwan 11,621 8.3 7,540 3.9 Singapore 6,105 4.3 13,632 7.0 Other Asian countries 11,435 8.1 8,229 4.2 Asia 58,435 41.5 66,164 33.9 Germany 7,573 5.4 8,261 4.2 Other European countries 15,853 11.3 13,188 6.7 Europe 23,426 16.7 21,449 10.9 Other Countries 376 0.3 107 0.1 Total $ 140,743 100.0 % $ 195,617 100.0 % The following table presents our net sales by extended warranty and service contracts recognized over time and our product and service revenue recognized at a point in time: Three Months Ended March 31, 2019 2018 Product and service revenue recognized at point in time $ 139,840 $ 194,683 Extended warranty and service contracts recognized over time 903 934 Total $ 140,743 $ 195,617 The following table presents our net sales by product line: Three Months Ended March 31, 2019 2018 Semiconductor capital market $ 67,514 $ 136,010 Industrial technology capital market 44,598 35,199 Global support 28,631 24,408 Total $ 140,743 $ 195,617

Revenue Revenue by Geographical

Revenue Revenue by Geographical Location (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table presents our net sales by extended warranty and service contracts recognized over time and our product and service revenue recognized at a point in time: Three Months Ended March 31, 2019 2018 Product and service revenue recognized at point in time $ 139,840 $ 194,683 Extended warranty and service contracts recognized over time 903 934 Total $ 140,743 $ 195,617 The following table presents our net sales by geographic region: Three Months Ended March 31, 2019 2018 Sales to external customers: United States $ 57,875 41.1 % $ 107,267 54.8 % Other North American countries 631 0.4 630 0.3 North America 58,506 41.5 107,897 55.1 Republic of Korea 13,800 9.8 24,893 12.7 People's Republic of China 15,474 11.0 11,870 6.1 Taiwan 11,621 8.3 7,540 3.9 Singapore 6,105 4.3 13,632 7.0 Other Asian countries 11,435 8.1 8,229 4.2 Asia 58,435 41.5 66,164 33.9 Germany 7,573 5.4 8,261 4.2 Other European countries 15,853 11.3 13,188 6.7 Europe 23,426 16.7 21,449 10.9 Other Countries 376 0.3 107 0.1 Total $ 140,743 100.0 % $ 195,617 100.0 % The following table presents our net sales by extended warranty and service contracts recognized over time and our product and service revenue recognized at a point in time: Three Months Ended March 31, 2019 2018 Product and service revenue recognized at point in time $ 139,840 $ 194,683 Extended warranty and service contracts recognized over time 903 934 Total $ 140,743 $ 195,617 The following table presents our net sales by product line: Three Months Ended March 31, 2019 2018 Semiconductor capital market $ 67,514 $ 136,010 Industrial technology capital market 44,598 35,199 Global support 28,631 24,408 Total $ 140,743 $ 195,617

Revenue 606 Financial Statement

Revenue 606 Financial Statement Impacts (Tables)	3 Months Ended
	Mar. 31, 2019
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

Discontinued Operations (Tables

Discontinued Operations (Tables)	3 Months Ended
	Mar. 31, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Groups, Including Discontinued Operations [Table Text Block]	Three Months Ended March 31, 2019 2018 Sales $ — $ — Cost of sales — 112 Total operating expense (benefit) — (61 ) Operating income (loss) from discontinued operations — (51 ) Other income (expense) (4 ) 124 Income (loss) from discontinued operations before income taxes (4 ) 73 Provision (benefit) for income taxes 5 (67 ) Income (loss) from discontinued operations, net of income taxes $ (9 ) $ 140 Assets and Liabilities of discontinued operations within the Condensed Consolidated Balance Sheets are comprised of the following: March 31, December 31, 2019 2018 Cash and cash equivalents $ 4,140 $ 5,251 Other current assets 430 406 Inventories 302 198 Current assets of discontinued operations $ 4,872 $ 5,855 Other assets $ — $ 67 Deferred income tax assets 5,917 5,917 Non-current assets of discontinued operations $ 5,917 $ 5,984 Accounts payable and other accrued expenses $ 349 $ 350 Accrued warranty 3,905 4,936 Current liabilities of discontinued operations $ 4,254 $ 5,286 Accrued warranty $ 10,344 $ 10,429 Other liabilities 142 286 Non-current liabilities of discontinued operations $ 10,486 $ 10,715

Income Taxes (Tables)

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of tax expense and the effective tax rate for our income from continuing operations	The following table sets out the tax expense and the effective tax rate for our income from continuing operations: Three Months Ended March 31, 2019 2018 Income from continuing operations, before income taxes $ 12,534 $ 56,129 Provision (benefit) for income taxes (2,853 ) 9,759 Effective tax rate (22.8 )% 17.4 %

Earnings Per Share (Tables)

Earnings Per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Reconciliation of the weighted-average shares outstanding used in the calculation of basic and diluted EPS	The following is a reconciliation of the weighted-average shares outstanding used in the calculation of basic and diluted EPS for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 Income from continuing operations $ 15,387 $ 46,370 Income from continuing operations attributable to noncontrolling interest 8 31 Income from continuing operations attributable to Advanced Energy Industries, Inc. $ 15,379 $ 46,339 Basic weighted-average common shares outstanding 38,198 39,619 Assumed exercise of dilutive stock options and restricted stock units 228 376 Diluted weighted-average common shares outstanding 38,426 39,995 Continuing operations: Basic earnings per share $ 0.40 $ 1.17 Diluted earnings per share $ 0.40 $ 1.16
Schedule of stock options and restricted units were excluded in the computation of diluted earnings per share because they were anti-dilutive	The following restricted stock units were excluded in the computation of diluted earnings per share because they were anti-dilutive: Three Months Ended March 31, 2019 2018 Restricted stock units 119 2

Marketable Securities (Tables)

Marketable Securities (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Fair Value, Assets Measured on Recurring Basis [Table Text Block]	March 31, 2019 and December 31, 2018 . The tables indicate the fair value hierarchy of the valuation techniques utilized to determine fair value. We did not have any financial liabilities measured at fair value, on a recurring basis, as of March 31, 2019 and December 31, 2018 . March 31, 2019 Level 1 Level 2 Level 3 Total Total marketable securities $ — $ 2,516 $ — $ 2,516 December 31, 2018 Level 1 Level 2 Level 3 Total Total marketable securities $ — $ 2,470 $ — $ 2,470
The composition of our marketable securities	Our marketable securities consist of certificates of deposit as follows: March 31, 2019 December 31, 2018 Cost Fair Value Cost Fair Value Total marketable securities $ 2,511 $ 2,516 $ 2,463 $ 2,470
The maturities of our marketable securities available for sale	The maturities of our marketable securities available for sale as of March 31, 2019 are as follows: Earliest Latest Certificates of deposit 4/10/2019 to 10/17/2019

Derivative Financial Instrume_2

Derivative Financial Instruments Gains and Losses related to Foreign Currency Contracts (Tables)	3 Months Ended
	Mar. 31, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) [Table Text Block]	During the three months ended March 31, 2019 and 2018 the gains and losses recorded related to the foreign currency exchange contracts are as follows: Three Months Ended March 31, 2019 2018 Foreign currency loss from foreign currency exchange contracts $ — $ (750 )

Accounts and Other Receivables

Accounts and Other Receivables (Tables)	3 Months Ended
	Mar. 31, 2018
Receivables [Abstract]
Schedule of Accounts, Notes, Loans and Financing Receivable	Components of accounts and other receivable, net of reserves, are as follows: March 31, December 31, 2019 2018 Amounts billed, net $ 87,607 $ 80,709 Unbilled receivables 14,798 19,733 Total receivables, net $ 102,405 $ 100,442

Inventories (Tables)

Inventories (Tables)	3 Months Ended
	Mar. 31, 2019
Inventory Disclosure [Abstract]
Components of inventories	Our inventories are valued at the lower of cost or net realizable value and computed on a first-in, first-out (FIFO) basis. Components of inventories are as follows: March 31, December 31, 2019 2018 Parts and raw materials $ 75,870 $ 76,647 Work in process 9,286 6,644 Finished goods 13,914 14,696 Total $ 99,070 $ 97,987

Property and Equipment (Tables)

Property and Equipment (Tables)	3 Months Ended
	Mar. 31, 2019
Property, Plant and Equipment [Abstract]
Details of property and equipment	Property and equipment, net is comprised of the following: March 31, December 31, 2019 2018 Buildings and land $ 1,719 $ 1,737 Machinery and equipment 42,985 41,330 Computer and communication equipment 24,721 24,051 Furniture and fixtures 3,189 3,203 Vehicles 282 282 Leasehold improvements 20,487 20,593 Construction in process 1,113 867 94,496 92,063 Less: Accumulated depreciation (63,438 ) (60,794 ) Property and equipment, net $ 31,058 $ 31,269
Depreciation expense recorded in continuing operations	Three Months Ended March 31, 2019 2018 Depreciation expense $ 2,208 $ 1,604

Goodwill (Tables)

Goodwill (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of the changes in goodwill	The following summarizes the changes in goodwill during the three months ended March 31, 2019 : Beginning Balance Effect of Changes in Exchange Rates Ending Balance March 31, 2019 $ 101,900 $ (594 ) $ 101,306

Intangible Assets (Tables)

Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of other intangible assets	ntangible assets consisted of the following as of March 31, 2019 and December 31, 2018 : March 31, 2019 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Technology $ 39,730 $ (8,967 ) $ 30,763 Customer relationships 35,416 (14,241 ) 21,175 Trademarks and other 2,518 (1,598 ) 920 Total $ 77,664 $ (24,806 ) $ 52,858 December 31, 2018 Gross Carrying Amount Accumulated Amortization Net Carrying Amount Technology $ 39,879 $ (7,927 ) $ 31,952 Customer relationships 35,509 (13,484 ) 22,025 Trademarks and other 2,501 (1,568 ) 933 Total $ 77,889 $ (22,979 ) $ 54,910
Schedule of amortization expense relating to other intangible assets	Three Months Ended March 31, 2019 2018 Amortization expense $ 1,973 $ 1,257
Schedule of expected future amortization expense	Estimated amortization expense related to intangibles is as follows: Year Ending December 31, 2019 (remaining) $ 5,612 2020 6,842 2021 6,743 2022 6,486 2023 6,468 Thereafter 20,707 Total $ 52,858

Restructuring Costs Restructuri

Restructuring Costs Restructuring Cost Cumulative Table (Tables)	3 Months Ended
	Mar. 31, 2019
Restructuring and Related Activities [Abstract]
Restructuring and Related Costs	The table below summarizes the restructuring charges: Three Months Ended March 31, 2019 Cumulative Cost Through March 31, 2019 Severance and related charges $ 153 $ 4,392 Facility relocation and closure charges 1,520 1,520 Total restructuring charges $ 1,673 $ 5,912
Schedule of Restructuring Reserve by Type of Cost	The following table summarizes our restructuring liabilities at March 31, 2019 : Balance at December 31, 2018 Cost Incurred and Charged to Expense Cost Paid or Otherwise Settled Effect of Changes in Exchange Rates Balance at March 31, 2019 Total restructuring liabilities $ 3,806 $ 1,673 $ (2,360 ) $ (11 ) $ 3,108

Warranties (Tables)

Warranties (Tables)	3 Months Ended
	Mar. 31, 2019
Product Warranties Disclosures [Abstract]
Changes in accrued product warranties	Three Months Ended March 31, 2019 2018 Balances at beginning of period $ 2,084 $ 2,312 Warranty liabilities acquired — 92 Increases to accruals 519 178 Warranty expenditures (345 ) (506 ) Effect of changes in exchange rates 6 8 Balances at end of period $ 2,264 $ 2,084

Leases (Tables)

Leases (Tables)	3 Months Ended
	Mar. 31, 2019
Leases [Abstract]
Maturities of lease liabilities	Maturities of our lease liabilities for all operating leases at March 31, 2019 are as follows: Year Ending December 31, 2019 (remaining) $ 6,003 2020 6,243 2021 5,937 2022 4,273 2023 2,974 Thereafter 17,928 Total lease payments $ 43,358 Less: Interest (6,464 ) Present value of lease liabilities $ 36,894
Additional lease information	Supplemental cash flow information related to our operating leases was as follows for the period ended March 31, 2019 : Cash paid for amounts included in the measurement of lease liabilities: Operating cash outflow from operating leases $ 2,891 The weighted average remaining lease term and discount rate for all of our operating leases were as follows as of March 31, 2019 : Weighted Average Remaining Lease Term Weighted Average Discount Rate Operating Leases 8.35 years 3.75 %

Pension Liability (Tables)

Pension Liability (Tables)	3 Months Ended
	Mar. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Schedule of Net Funded Status [Table Text Block]	The net pension liability is included in Other long-term liabilities in our balance sheet as follows: March 31, December 31, 2019 2018 Pension liability $ 19,874 $ 19,266
Schedule of Net Benefit Costs [Table Text Block]	the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 2018 Interest cost $ 199 $ 218 Expected return on plan assets (170 ) (161 ) Amortization of actuarial gains and losses 118 136 Net periodic pension cost $ 147 $ 193

Stock-Based Compensation (Table

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Schedule of stock-based compensation		Stock-based compensation for the three months ended March 31, 2019 and 2018 was as follows: Three Months Ended March 31, 2019 2018 Stock-based compensation expense $ 3,199 $ 4,494
Summary of stock option activity	Three Months Ended March 31, 2019 Number of RSUs Weighted-Average Grant Date Fair Value RSUs outstanding at beginning of period 352 $ 58.17 RSUs granted 331 $ 51.94 RSUs vested (96 ) $ 48.14 RSUs forfeited (10 ) $ 32.19 RSUs outstanding at end of period 577 $ 56.73 Changes in the outstanding stock option awards during the three months ended March 31, 2019 were as follows: Three Months Ended March 31, 2019 Number of Options Weighted-Average Exercise Price per Share Options outstanding at beginning of period 230 $ 20.73 Options exercised (9 ) $ 10.50 Options expired (1 ) $ 7.69 Options outstanding at end of period 220 $ 21.21

Related Party Transactions (Tab

Related Party Transactions (Tables)	3 Months Ended
	Mar. 31, 2019
Related Party Transaction [Line Items]
Schedule of related party transactions	Members of our Board of Directors hold various executive positions and serve as directors at other companies, including companies that are our customers. During the three months ended March 31, 2019 , we engaged in the following transactions with companies related to members of our Board of Directors, as described below: Three Months Ended March 31, 2019 2018 Sales to related parties $ 352 $ 73 Number of related party customers 1 1 Our accounts receivable balance from related party customers with outstanding balances as of March 31, 2019 and December 31, 2018 is as follows: March 31, December 31, 2019 2018 Accounts receivable from related parties $ 154 $ 109 Number of related party customers 1 1

Geographic and Customer Infor_2

Geographic and Customer Information (Tables)	3 Months Ended
	Mar. 31, 2019
Significant Customer Information [Abstract]
Schedule of Revenue by Major Customers by Reporting Segments [Table Text Block]	The following table summarizes sales, and percentages of sales, by customers that individually accounted for 10% or more of our sales for the three months ended March 31, 2019 and 2018 : Three Months Ended March 31, 2019 % of Total Sales 2018 % of Total Sales Applied Materials, Inc. $ 36,290 25.8 % $ 69,872 35.7 % LAM Research 19,667 14.0 % 39,726 20.3 % The following table summarizes the accounts receivable balances, and percentages of the total accounts receivable, for customers that individually accounted for 10% or more of accounts receivable as of March 31, 2019 and December 31, 2018 : March 31, December 31, 2019 2018 Applied Materials, Inc. $ 27,150 26.5 % $ 34,301 34.2 % LAM Research 11,941 11.7 % 12,181 12.1 %

Basis of Presentation - Cumulat

Basis of Presentation - Cumulative Effect of Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating lease right-of-use assets	$ 35,654		$ 0
Operating Lease, Liability	$ 36,894
Accounting Standards Update 2016-02 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Operating lease right-of-use assets		$ 38,211
Operating Lease, Liability		$ 38,384

Business Acquisition - (Details

Business Acquisition - (Details) $ in Thousands	1 Months Ended
	Sep. 30, 2018USD ($)
LumaSense Technology Holdings Inc. [Member]
Business Acquisition [Line Items]
Payments to Acquire Businesses, Gross	$ 94,946

Business Acquisition Considerat

Business Acquisition Consideration Transferred (Details) - LumaSense Technology Holdings Inc. [Member] $ in Thousands	1 Months Ended
	Sep. 30, 2018USD ($)
Business Acquisition [Line Items]
Cash paid for acquisition, net of working capital adjustments	$ 94,946
Cash acquired	(10,262)
Total fair value of consideration transferred	$ 84,684

Business Acquisition Assets Acq

Business Acquisition Assets Acquired and Liabilities Assumed (Details) - LumaSense Technology Holdings Inc. [Member] - USD ($) $ in Thousands	1 Months Ended
	Sep. 30, 2018	Sep. 01, 2018
Business Acquisition [Line Items]
Assets acquired and liabilities assumed, net		$ 7,167
Inventories		9,372
Property and equipment		1,353
Goodwill		48,032
Intangible assets		26,000
Deferred income tax assets		8,116
Other assets		5,126
Total assets acquired		105,166
Accounts payable		5,734
Deferred income tax liabilities		7,984
Other liabilities		6,764
Total liabilities assumed		20,482
Total fair value of consideration received	$ 84,684
Tradename [Member]
Business Acquisition [Line Items]
Intangible assets		20,000
Customer Relationships [Member]
Business Acquisition [Line Items]
Intangible assets		$ 6,000

Business Acquisition Intangible

Business Acquisition Intangible Assets Acquired (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Sep. 01, 2018
Tradename [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Life	10 years
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful Life	10 years
LumaSense Technology Holdings Inc. [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets:		$ 26,000
LumaSense Technology Holdings Inc. [Member] | Tradename [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets:		20,000
LumaSense Technology Holdings Inc. [Member] | Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Amortizable intangible assets:		$ 6,000

Business Acquisition Unaudited

Business Acquisition Unaudited Pro Forma Results (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Business Acquisition, Pro Forma Information [Abstract]
Total sales, as reported	$ 140,743	$ 195,617
Total sales, pro forma	140,743	210,465
Net income attributable to Advanced Energy Industries, Inc, as reported.	15,370	46,479
Net income attributable to Advanced Energy Industries, Inc., pro forma	$ 15,491	$ 46,310
Earnings Per Share, Pro Forma [Abstract]
Basic earnings per share, as reported	$ 0.40	$ 1.17
Basic earnings per share, pro forma	0.41	1.17
Diluted earnings per share, as reported	0.40	1.16
Diluted earnings per share, pro forma	$ 0.40	$ 1.16
Net income	$ 15,378	$ 46,510
LumaSense Technology Holdings Inc. [Member]
Business Acquisition, Pro Forma Information [Abstract]
Total sales, as reported	12,000
Earnings Per Share, Pro Forma [Abstract]
Net income	$ 900

Revenue - Extended Warranty Rev

Revenue - Extended Warranty Revenue (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 140,743	$ 195,617
Transferred over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	903	934
Transferred at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 139,840	$ 194,683

Revenue Revenue by product li_2

Revenue Revenue by product line (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 140,743	$ 195,617
CANADA
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	631	630
UNITED STATES
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	57,875	107,267
North America [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	58,506	107,897
CHINA
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	15,474	11,870
KOREA, REPUBLIC OF
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	13,800	24,893
TAIWAN, PROVINCE OF CHINA
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	11,621	7,540
SINGAPORE
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	6,105	13,632
Other Asian Countries [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	11,435	8,229
Asia [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	58,435	66,164
GERMANY
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	7,573	8,261
Other European Countries [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	15,853	13,188
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	23,426	21,449
Other countries [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	376	107
Semiconductor Capital Marker [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	67,514	136,010
Industrial Power Capital Market [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	44,598	35,199
Global Support [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 28,631	$ 24,408
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	100.00%	100.00%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | CANADA
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	0.40%	0.30%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | UNITED STATES
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	41.10%	54.80%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | North America [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	41.50%	55.10%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | CHINA
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	9.80%	12.70%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | KOREA, REPUBLIC OF
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	11.00%	6.10%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | TAIWAN, PROVINCE OF CHINA
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	8.30%	3.90%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | SINGAPORE
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	4.30%	7.00%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | Other Asian Countries [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	8.10%	4.20%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | Asia [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	41.50%	33.90%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | GERMANY
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	5.40%	4.20%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | Other European Countries [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	11.30%	6.70%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | Europe [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	16.70%	10.90%
Geographic Concentration Risk [Member] | Sales Revenue, Net [Member] | Other countries [Member]
Disaggregation of Revenue [Line Items]
Concentration Risk, Percentage	0.30%	0.10%

Revenue Narrative (Details)

Revenue Narrative (Details) - USD ($) $ in Millions	192 Months Ended
	Dec. 31, 2034	Mar. 31, 2019	Dec. 31, 2018
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Deferred Service Revenue		$ 32.5	$ 33.4
Minimum [Member] | Subsequent Event [Member] | Scenario, Forecast [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Recognition of Deferred Revenue, Expected Annual Amount	$ 0.1
Maximum [Member] | Subsequent Event [Member] | Scenario, Forecast [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Recognition of Deferred Revenue, Expected Annual Amount	$ 3.5

Discontinued Operations Stateme

Discontinued Operations Statement of Operations for Discontinued Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sales	$ 0	$ 0
Cost of sales	0	112
Total operating expense (benefit)	0	(61)
Operating income (loss) from discontinued operations	0	(51)
Other income (expense)	(4)
Other income (expense)		124
Provision (benefit) for income taxes	(4)	73
Provision (benefit) for income taxes	5	(67)
Income (loss) from discontinued operations, net of income taxes	$ (9)	$ 140

Discontinued Operations Assets

Discontinued Operations Assets and Liabilities of Discontinued Operations (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 4,140	$ 5,251	$ 7,654
Accounts and other receivables, net	430	406
Inventories	302	198
Current assets of discontinued operations	4,872	5,855
Other assets	0	67
Deferred income tax assets	5,917	5,917
Non-current assets of discontinued operations	5,917	5,984
Accounts payable and other accrued expenses	349	350
Accrued warranty	3,905	4,936
Current liabilities of discontinued operations	4,254	5,286
Accrued warranty	10,344	10,429
Other liabilities	142	286
Non-current liabilities of discontinued operations	$ 10,486	$ 10,715

Income Taxes Schedule of tax ex

Income Taxes Schedule of tax expense and the effective tax rate for our income from continuing operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Income Tax Disclosure [Abstract]
Income from continuing operations, before income taxes	$ 12,534	$ 56,129
Provision (benefit) for income taxes	$ (2,853)	$ 9,759
Effective tax rate	(22.80%)	17.40%

Income Taxes Narrative (Details

Income Taxes Narrative (Details)	3 Months Ended
	Mar. 31, 2019
Details [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%

Earnings Per Share Reconciliati

Earnings Per Share Reconciliation of the weighted-average shares outstanding used in the calculation of basic and diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Income from continuing operations	$ 15,387	$ 46,370
Income from continuing operations attributable to noncontrolling interest	8	31
Income from continuing operations attributable to Advanced Energy Industries, Inc.	$ 15,379	$ 46,339
Basic weighted-average common shares outstanding	38,198	39,619
Assumed exercise of dilutive stock options and restricted stock units	228	376
Diluted weighted-average common shares outstanding	38,426	39,995
Income from Continuing Operations:
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.40	$ 1.17
Income (Loss) from Continuing Operations, Per Diluted Share	$ 0.40	$ 1.16

Earnings Per Share Schedule of

Earnings Per Share Schedule of stock options and restricted units were excluded in the computation of diluted earnings per share because they were anti-dilutive (Details) - shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock options and restricted units excluded from the computation of diluted earnings per share because they were anti-dilutive	119	2

Earnings Per Share Stock Buybac

Earnings Per Share Stock Buyback (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	May 03, 2018	Sep. 16, 2015
Equity, Class of Treasury Stock [Line Items]
Authorized amount				$ 150,000
StockRepurchaseProgramAuthorizedAmountIncreased			$ 50,000
Amount paid to repurchase shares	$ 0	$ 12,750
Number of shares repurchased	0	181
Average repurchase price per share	$ 0	$ 70.47
Remaining authorized repurchase amount	$ 24,900

Marketable Securities (Details)

Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	$ 2,516	$ 2,470
Debt Securities, Available-for-sale, Amortized Cost	$ 2,511	$ 2,463

Marketable Securities The matur

Marketable Securities The maturities of our marketable securities available for sale (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	$ 2,516	$ 2,470
Debt Securities, Available-for-sale, Amortized Cost	$ 2,511	$ 2,463
Certificates of Deposit [Member] | Minimum [Member]
Debt Securities, Available-for-sale [Line Items]
Maturities of marketable securites, by date	Apr. 10, 2019
Certificates of Deposit [Member] | Maximum [Member]
Debt Securities, Available-for-sale [Line Items]
Maturities of marketable securites, by date	Oct. 17, 2019

Marketable Securities Compositi

Marketable Securities Composition of Marketable Securities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Available-for-sale Securities	$ 2,516	$ 2,470
Debt Securities, Available-for-sale, Amortized Cost	$ 2,511	$ 2,463

Marketable Securities Fair Valu

Marketable Securities Fair Value of our Marketable Securities (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Assets, Fair Value Disclosure	$ 2,516	$ 2,470
Fair Value, Inputs, Level 1 [Member]
Debt Securities, Available-for-sale [Line Items]
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Debt Securities, Available-for-sale [Line Items]
Assets, Fair Value Disclosure	2,516	2,470
Fair Value, Inputs, Level 3 [Member]
Debt Securities, Available-for-sale [Line Items]
Assets, Fair Value Disclosure	$ 0	$ 0

Derivative Financial Instrume_3

Derivative Financial Instruments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Dec. 31, 2018
Derivative [Line Items]
Derivative, notional amount		$ 16.3
Gain (Loss) on Foreign Currency Cash Flow Hedge Ineffectiveness	$ 3.5

Derivative Financial Instrume_4

Derivative Financial Instruments Gain (loss) on foreign currency exchange contracts (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Foreign Exchange [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ (750)

Accounts and Other Receivable_2

Accounts and Other Receivables Components of Accounts and Other Receivables (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total receivables, net	$ 102,405	$ 100,442
Amounts billed, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total receivables, net	87,607	80,709
Unbilled receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total receivables, net	$ 14,798	$ 19,733

Inventories Components of inven

Inventories Components of inventories (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Inventory Disclosure [Abstract]
Parts and raw materials	$ 75,870	$ 76,647
Work in process	9,286	6,644
Finished goods	13,914	14,696
Inventory, Net	$ 99,070	$ 97,987

Property and Equipment Details

Property and Equipment Details of property and equipment (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 94,496	$ 92,063
Less: Accumulated depreciation	(63,438)	(60,794)
Property and equipment, net	31,058	31,269
Buildings and Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,719	1,737
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	42,985	41,330
Computer and Communication Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	24,721	24,051
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	3,189	3,203
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	282	282
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	20,487	20,593
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 1,113	$ 867

Property and Equipment Deprecia

Property and Equipment Depreciation expense recorded in continuing operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 2,208	$ 1,604

Goodwill Schedule of the change

Goodwill Schedule of the changes in goodwill (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Goodwill [Roll Forward]
Beginning Balance	$ 101,900
Effect of Changes in Exchange Rates	(594)
Ending Balance	$ 101,306

Intangible Assets Schedule of o

Intangible Assets Schedule of other intangible assets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 77,664	$ 77,889
Finite-Lived Intangible Assets, Accumulated Amortization	(24,806)	(22,979)
Finite-lived intangible assets, net	52,858	54,910
Technology-based [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	39,730	39,879
Finite-Lived Intangible Assets, Accumulated Amortization	(8,967)	(7,927)
Finite-lived intangible assets, net	30,763	31,952
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	35,416	35,509
Finite-Lived Intangible Assets, Accumulated Amortization	(14,241)	(13,484)
Finite-lived intangible assets, net	21,175	22,025
Trademarks and other [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	2,518	2,501
Finite-Lived Intangible Assets, Accumulated Amortization	(1,598)	(1,568)
Finite-lived intangible assets, net	$ 920	$ 933

Intangible Assets Schedule of a

Intangible Assets Schedule of amortization expense relating to other intangible assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 77,664		$ 77,889
Finite-Lived Intangible Assets, Accumulated Amortization	(24,806)		(22,979)
Finite-lived intangible assets, net	52,858		54,910
Amortization expense	1,973	$ 1,257
Technology Equipment [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	39,730		39,879
Finite-Lived Intangible Assets, Accumulated Amortization	(8,967)		(7,927)
Finite-lived intangible assets, net	$ 30,763		$ 31,952

Intangible Assets Schedule of F

Intangible Assets Schedule of Finite-Lived Intangible Assets, Future Amortization Expense (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
2016 (remaining)	$ 5,612
2017	6,842
2018	6,743
2019	6,486
2020	6,468
Thereafter	20,707
Finite-lived intangible assets, net	$ 52,858	$ 54,910

Restructuring Costs Schedule of

Restructuring Costs Schedule of Restructuring Reserve by Cost Type (Details) - USD ($) $ in Thousands	3 Months Ended		15 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1,673	$ 0	$ 5,912
Severance and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	153		4,392
Facility relocation and closure charges
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 1,520		$ 1,520

Restructuring Costs Restructu_2

Restructuring Costs Restructuring liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		15 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019
Restructuring Reserve [Roll Forward]
Beginning balance	$ 3,806
Cost incurred and charged to expense	1,673	$ 0	$ 5,912
Cost paid or otherwise settled	2,360
Effect of change in exchange rates	(11)
Ending balance	3,108		3,108
Severance and related charges
Restructuring Reserve [Roll Forward]
Cost incurred and charged to expense	153		4,392
Facility relocation and closure charges
Restructuring Reserve [Roll Forward]
Cost incurred and charged to expense	$ 1,520		$ 1,520

Warranties Narrative (Details)

Warranties Narrative (Details)	3 Months Ended
	Mar. 31, 2019
Minimum [Member]
Product Liability Contingency [Line Items]
Standard Product Warranty Term	12 months
Maximum [Member]
Product Liability Contingency [Line Items]
Standard Product Warranty Term	24 months

Warranties Changes in accrued p

Warranties Changes in accrued product warranties (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Movement in Standard Product Warranty Accrual [Roll Forward]
Balances at beginning of period	$ 2,084	$ 2,312
Warranty liabilities acquired	0	92
Increases to accruals	519	178
Warranty expenditures	(345)	(506)
Effect of changes in exchange rates	6	8
Balances at end of period	$ 2,264	$ 2,084

Leases (Details)

Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Apr. 01, 2019	Mar. 31, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Operating lease right-of-use asset			$ 35,654	$ 0
Operating Lease, Liability			$ 36,894
Metzingen, Germany [Member] | Subsequent Event [Member]
Lessee, Lease, Description [Line Items]
Lease term		3 years
Operating lease right-of-use asset		$ 1,200
Operating Lease, Liability		$ 1,200
Denver, Colorado [Member] | Subsequent Event [Member]
Lessee, Lease, Description [Line Items]
Lease term	10 years
Operating lease right-of-use asset	$ 15,700
Operating Lease, Liability	$ 15,700

Leases Operating lease maturity

Leases Operating lease maturity schedule (Details) $ in Thousands	Mar. 31, 2019USD ($)
Leases [Abstract]
2019, remaining	$ 6,003
2020	6,243
2021	5,937
2022	4,273
2023	2,974
Thereafter	17,928
Total lease payments	43,358
Less: Interest	(6,464)
Present value of lease liabilities	$ 36,894

Leases Additional lease cost in

Leases Additional lease cost information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)
Leases [Abstract]
Weighted Average Remaining Lease Term	8 years 4 months 6 days
Weighted Average Discount Rate	3.75%
Operating cash outflow from operating leases	$ 2,891

Pension Liability (Details)

Pension Liability (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ 19,874		$ 19,266
Defined Benefit Plan, Interest Cost	199	$ 218
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	(170)	(161)
Pension Cost (Reversal of Cost)	147	$ 193
Payments through April 30, 2024 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	900
Payments from May 1, 2024 through November 30, 2033 [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	$ 1,800

Pension Liability Net Periodic

Pension Liability Net Periodic Pension Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Postemployment Benefits [Abstract]
Defined Benefit Plan, Expected Return (Loss) on Plan Assets	$ 170	$ 161
Defined Benefit Plan, Interest Cost	199	218
Defined Benefit Plan, Amortization of Gain (Loss)	118	136
Pension Cost (Reversal of Cost)	$ 147	$ 193

Pension Liability Net Pension L

Pension Liability Net Pension Liability (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Funded (Unfunded) Status of Plan	$ 19,874	$ 19,266

Stock-Based Compensation Schedu

Stock-Based Compensation Schedule of stock-based compensation (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-based compensation expense	$ 3,199	$ 4,494

Stock-Based Compensation Summar

Stock-Based Compensation Summary of stock option activity (Details) - Time Based [Member] - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	220	230
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price	$ 21.21	$ 20.73
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period	(9)
Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price	$ 10.50
Share-based Compensation Arrangement by Share-based Payment Award, Options, Expirations in Period	(1)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 7.69

Stock-Based Compensation Summ_2

Stock-Based Compensation Summary of non-vested Restricted Stock Units activity (Details) - Restricted Stock Units (RSUs) [Member] - $ / shares shares in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 51.94
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 32.19
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	577	352
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	331
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 48.14
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(96)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(10)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 56.73	$ 58.17

Stock-Based Compensation Narrat

Stock-Based Compensation Narrative (Details) shares in Millions	Mar. 31, 2019shares
2017 OMNIBUS Incentive Plan [Member] [Domain]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	2.3

Commitments and Contingencies (

Commitments and Contingencies (Details) $ in Millions	Mar. 31, 2019USD ($)
Other Commitments [Line Items]
Purchase Commitment, Remaining Minimum Amount Committed	$ 99.4

Related Party Transactions (Det

Related Party Transactions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)Companies	Mar. 31, 2018Companies	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Related Party Transactions, Number of Companies	1	1
Accounts Receivable, Related Parties | $	$ 154		$ 109
Management [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Number of Companies	1	1

Related Party Transactions Sche

Related Party Transactions Schedule of related party transactions (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)Companies	Mar. 31, 2018USD ($)Companies	Dec. 31, 2018USD ($)
Related Party Transaction [Line Items]
Accounts Receivable, Related Parties | $	$ 154		$ 109
Sales - related parties | $	$ 352	$ 73
Related Party Transactions, Number of Companies | Companies	1	1
Management [Member]
Related Party Transaction [Line Items]
Related Party Transactions, Number of Companies | Companies	1	1

Geographic and Customer Infor_3

Geographic and Customer Information Significant Customer Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 140,743	$ 195,617
Applied Materials, Inc. [Member] | Sales Revenue, Goods, Net [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	25.80%	35.70%
Lam Research [Member] | Sales Revenue, Goods, Net [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	14.00%	20.30%
Accounts Receivable [Member] | Applied Materials, Inc. [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	26.50%	34.20%
Concentration Risk, Amount	$ 27,150		$ 34,301
Accounts Receivable [Member] | Lam Research [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration Risk, Percentage	11.70%	12.10%
Concentration Risk, Amount	$ 11,941		$ 12,181
Product [Member]
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	112,112	$ 171,209
Product [Member] | Applied Materials, Inc. [Member] | Sales Revenue, Goods, Net [Member]
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	36,290	69,872
Product [Member] | Lam Research [Member] | Sales Revenue, Goods, Net [Member]
Concentration Risk [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 19,667	$ 39,726

Credit Facility (Details)

Credit Facility (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2019USD ($)	Mar. 31, 2018USD ($)
Line of Credit Facility [Line Items]
Interest Expense	$ 56	$ 56
Bank of America N.A. [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Current Borrowing Capacity	$ 150,000
Debt, Weighted Average Interest Rate	3.75%
Funded Debt To EBITDA Ratio	2
London Interbank Offered Rate (LIBOR) [Member] | Bank of America N.A. [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.25%
Funded Debt To EBITDA Ratio [Member] | Bank of America N.A. [Member] | Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.75%