Advanced Energy Industries (AEIS) 10-Q 9 Nov 21 2021 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2021	Nov. 01, 2021
Document and Entity Information
Document Type	10-Q
Document Quarterly Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Entity File Number	000-26966
Entity Registrant Name	ADVANCED ENERGY INDUSTRIES INC
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	84-0846841
Entity Address, Address Line One	1595 Wynkoop Street, Suite 800
Entity Address, City or Town	Denver
Entity Address, State or Province	CO
Entity Address, Postal Zip Code	80202
City Area Code	970
Local Phone Number	407-6626
Title of 12(b) Security	Common Stock, $0.001 par value
Trading Symbol	AEIS
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		37,669,635
Entity Central Index Key	0000927003
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q3
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 547,923	$ 480,368
Marketable securities	2,833	2,654
Accounts and other receivable, net	220,112	235,178
Inventories	341,500	221,346
Income taxes receivable	19,005	4,804
Other current assets	32,984	35,899
Total current assets	1,164,357	980,249
Property and equipment, net	114,801	114,731
Operating lease right-of-use assets	104,179	103,858
Deposits and other assets	19,067	19,101
Goodwill	213,625	209,983
Intangible assets, net	165,032	168,939
Deferred income tax assets	50,994	50,801
TOTAL ASSETS	1,832,055	1,647,662
Current liabilities:
Accounts payable	190,228	125,224
Income taxes payable	14,787	11,850
Accrued payroll and employee benefits	56,141	63,487
Other accrued expenses	65,189	49,565
Customer deposits and other	24,806	12,179
Current portion of long-term debt	20,000	17,500
Current portion of operating lease liabilities	16,137	16,592
Total current liabilities	387,288	296,397
Long-term debt, net	377,597	304,546
Operating lease liabilities	96,337	95,993
Pension benefits	76,876	80,447
Deferred income tax liabilities	9,606	10,088
Uncertain tax positions	12,874	12,839
Long-term deferred revenue	6,563	7,352
Other long-term liabilities	23,123	24,660
Total liabilities	990,264	832,322
Commitments and contingencies (Note 17)
Stockholders' equity:
Preferred stock, $0.001 par value, 1,000 shares authorized, none issued and outstanding
Common stock, $0.001 par value, 70,000 shares authorized; 37,790 and 38,293 issued and outstanding at September 30, 2021 and December 31, 2020, respectively	38	38
Additional paid-in capital	105,923	105,009
Accumulated other comprehensive loss	(9,714)	(2,605)
Retained earnings	744,873	712,297
Advanced Energy stockholders' equity	841,120	814,739
Noncontrolling interest	671	601
Total stockholders' equity	841,791	815,340
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 1,832,055	$ 1,647,662

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares shares in Thousands	Sep. 30, 2021	Dec. 31, 2020
Consolidated Balance Sheets
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 (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	70,000	70,000
Common stock, shares issued (in shares)	37,790	38,293
Common stock, shares outstanding (in shares)	37,790	38,293

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Consolidated Statements of Operations
Sales, net	$ 346,093	$ 389,521	$ 1,059,024	$ 1,044,857
Cost of sales	226,054	235,736	666,449	648,537
Gross profit	120,039	153,785	392,575	396,320
Operating expenses:
Research and development	40,578	36,807	120,865	107,432
Selling, general, and administrative	48,373	51,481	143,214	145,646
Amortization of intangible assets	5,607	5,049	16,504	15,064
Restructuring expense	1,272	1,494	2,521	7,940
Total operating expenses	95,830	94,831	283,104	276,082
Operating income	24,209	58,954	109,471	120,238
Other income (expense), net	495	(6,558)	(3,674)	(11,655)
Income from continuing operations, before income taxes	24,704	52,396	105,797	108,583
Provision for income taxes	3,657	6,783	10,817	15,293
Income from continuing operations	21,047	45,613	94,980	93,290
Income (loss) from discontinued operations, net of income taxes	(37)	50	171	(421)
Net income	21,010	45,663	95,151	92,869
Income from continuing operations attributable to noncontrolling interest	6	36	70	35
Net income attributable to Advanced Energy Industries, Inc.	$ 21,004	$ 45,627	$ 95,081	$ 92,834
Basic weighted-average common shares outstanding	38,183	38,325	38,296	38,322
Diluted weighted-average common shares outstanding	38,363	38,528	38,517	38,531
Earnings per share:
Continuing operations: Basic earnings per share	$ 0.55	$ 1.19	$ 2.48	$ 2.43
Continuing operations: Diluted earnings per share	0.55	1.18	2.46	2.42
Discontinued operations: Basic earnings (loss) per share				(0.01)
Discontinued operations: Diluted earnings (loss) per share				(0.01)
Net income:
Basic earnings per share	0.55	1.19	2.48	2.42
Diluted earnings per share	$ 0.55	$ 1.19	$ 2.47	$ 2.41

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Consolidated Statements of Comprehensive Income
Net income	$ 21,010	$ 45,663	$ 95,151	$ 92,869
Other comprehensive income (loss), net of income taxes
Foreign currency translation	(3,661)	5,267	(9,534)	4,706
Change in fair value of cash flow hedges	172	170	2,179	(2,674)
Minimum benefit retirement liability	313	(116)	246	38
Comprehensive income	17,834	50,984	88,042	94,939
Comprehensive income attributable to noncontrolling interest	6	36	70	35
Comprehensive income attributable to Advanced Energy Industries, Inc.	$ 17,828	$ 50,948	$ 87,972	$ 94,904

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income	Retained EarningsCumulative Effect, Period of Adoption, Adjustment [Member]	Retained Earnings	Non-controlling Interest	Cumulative Effect, Period of Adoption, Adjustment [Member]	Total
Beginning Balance at Dec. 31, 2019	$ 38	$ 104,849	$ (5,897)	$ (102)	$ 577,724	$ 546	$ (102)	$ 677,260
Beginning Balance (in shares) at Dec. 31, 2019	38,358
Stock issued from equity plans		(2,171)						(2,171)
Stock issued from equity plans (in shares)	64
Stock-based compensation		3,048						3,048
Stock buyback		(7,248)						(7,248)
Stock buyback (in shares)	(170)
Other comprehensive income (loss)			(2,907)					(2,907)
Net income					18,063	15		18,078
Ending Balance at Mar. 31, 2020	$ 38	98,478	(8,804)		595,685	561		685,958
Ending Balance (in shares) at Mar. 31, 2020	38,252
Beginning Balance at Dec. 31, 2019	$ 38	104,849	(5,897)	$ (102)	577,724	546	$ (102)	677,260
Beginning Balance (in shares) at Dec. 31, 2019	38,358
Stock buyback								(11,579)
Net income								92,869
Ending Balance at Sep. 30, 2020	$ 38	101,485	(3,827)		670,456	581		768,733
Ending Balance (in shares) at Sep. 30, 2020	38,272
Beginning Balance at Mar. 31, 2020	$ 38	98,478	(8,804)		595,685	561		685,958
Beginning Balance (in shares) at Mar. 31, 2020	38,252
Stock issued from equity plans		779						779
Stock issued from equity plans (in shares)	73
Stock-based compensation		2,837						2,837
Other comprehensive income (loss)			(344)					(344)
Net income					29,144	(16)		29,128
Ending Balance at Jun. 30, 2020	$ 38	102,094	(9,148)		624,829	545		718,358
Ending Balance (in shares) at Jun. 30, 2020	38,325
Stock issued from equity plans		(59)						(59)
Stock issued from equity plans (in shares)	20
Stock-based compensation		3,781						3,781
Stock buyback		(4,331)						(4,331)
Stock buyback (in shares)	(73)
Other comprehensive income (loss)			5,321					5,321
Net income					45,627	36		45,663
Ending Balance at Sep. 30, 2020	$ 38	101,485	(3,827)		670,456	581		768,733
Ending Balance (in shares) at Sep. 30, 2020	38,272
Beginning Balance at Dec. 31, 2020	$ 38	105,009	(2,605)		712,297	601		$ 815,340
Beginning Balance (in shares) at Dec. 31, 2020	38,293							38,293
Stock issued from equity plans		(4,645)						$ (4,645)
Stock issued from equity plans (in shares)	93
Stock-based compensation		5,701						5,701
Dividend payments					(3,854)			(3,854)
Other comprehensive income (loss)			(4,968)					(4,968)
Net income					38,668	33		38,701
Ending Balance at Mar. 31, 2021	$ 38	106,065	(7,573)		747,111	634		846,275
Ending Balance (in shares) at Mar. 31, 2021	38,386
Beginning Balance at Dec. 31, 2020	$ 38	105,009	(2,605)		712,297	601		$ 815,340
Beginning Balance (in shares) at Dec. 31, 2020	38,293							38,293
Stock buyback								$ (59,058)
Net income								95,151
Ending Balance at Sep. 30, 2021	$ 38	105,923	(9,714)		744,873	671		$ 841,791
Ending Balance (in shares) at Sep. 30, 2021	37,790							37,790
Beginning Balance at Mar. 31, 2021	$ 38	106,065	(7,573)		747,111	634		$ 846,275
Beginning Balance (in shares) at Mar. 31, 2021	38,386
Stock issued from equity plans		956						956
Stock issued from equity plans (in shares)	67
Stock-based compensation		3,277						3,277
Stock buyback		(6,503)						(6,503)
Stock buyback (in shares)	(72)
Dividend payments					(3,874)			(3,874)
Other comprehensive income (loss)			1,035					1,035
Net income					35,409	31		35,440
Ending Balance at Jun. 30, 2021	$ 38	103,795	(6,538)		778,646	665		876,606
Ending Balance (in shares) at Jun. 30, 2021	38,381
Stock issued from equity plans		223						223
Stock issued from equity plans (in shares)	14
Stock-based compensation		3,540						3,540
Stock buyback		(1,635)			(50,920)			(52,555)
Stock buyback (in shares)	(605)
Dividend payments					(3,857)			(3,857)
Other comprehensive income (loss)			(3,176)					(3,176)
Net income					21,004	6		21,010
Ending Balance at Sep. 30, 2021	$ 38	$ 105,923	$ (9,714)		$ 744,873	$ 671		$ 841,791
Ending Balance (in shares) at Sep. 30, 2021	37,790							37,790

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 95,151	$ 92,869
Income (loss) from discontinued operations, net of income taxes	171	(421)
Income from continuing operations, net of income taxes	94,980	93,290
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	39,225	35,433
Stock-based compensation expense	12,819	9,666
Provision for deferred income taxes	(1,404)	(7,849)
Gain (Loss) from discount on notes receivable	(638)	721
Loss on disposal of assets	923	678
Changes in operating assets and liabilities, net of assets acquired:
Accounts and other receivable, net	14,957	8,670
Inventories	(118,562)	(26,983)
Other assets	1,958	5,039
Accounts payable	63,404	(12,971)
Other liabilities and accrued expenses	8,963	30,964
Income taxes	(10,215)	(1,626)
Net cash from operating activities from continuing operations	106,410	135,032
Net cash from operating activities from discontinued operations	(523)	(659)
Net cash from operating activities	105,887	134,373
CASH FLOWS FROM INVESTING ACTIVITIES:
Net proceeds from sale of marketable securities		3
Receipts (issuance) of notes receivable	802	(1,000)
Proceeds from sale of assets	1,537	103
Purchases of property and equipment	(22,721)	(25,232)
Acquisitions, net of cash acquired	(18,739)	(1,127)
Net cash from investing activities from continuing operations	(39,121)	(27,253)
Net cash from investing activities	(39,121)	(27,253)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from long-term borrowings	85,000
Payment of debt-issuance costs	(1,350)
Payments on long-term borrowings	(8,750)	(13,125)
Dividend payments	(11,585)
Purchase and retirement of common stock	(56,625)	(11,579)
Net payments related to stock-based awards	(3,136)	(1,451)
Net cash from financing activities from continuing operations	3,554	(26,155)
Net cash from financing activities	3,554	(26,155)
EFFECT OF CURRENCY TRANSLATION ON CASH	(2,765)	1,571
NET CHANGE IN CASH AND CASH EQUIVALENTS	67,555	82,536
CASH AND CASH EQUIVALENTS, beginning of period	480,368	346,441
CASH AND CASH EQUIVALENTS, end of period	547,923	428,977
CASH AND CASH EQUIVALENTS FROM CONTINUING OPERATIONS, end of period	547,923	428,977
SUPPLEMENTAL DISCLOSURE OF CASH FLOW INFORMATION:
Cash paid for interest	2,896	4,261
Cash paid for income taxes	25,271	16,079
Cash received for refunds of income taxes	$ 3,116	$ 821

DESCRIPTION OF BUSINESS AND BAS

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	9 Months Ended
	Sep. 30, 2021
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION	NOTE 1. DESCRIPTION OF BUSINESS AND 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, 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 several industrial markets. Our network of service support centers facilitates local repair and field service in key regions, provides upgrades and refurbishment services, and sells used equipment to businesses that use our products. In September 2019, we acquired the Artesyn Embedded Power business ("Artesyn"), which added new power products and technologies used in networking and computing, data center, including hyperscale, and industrial and medical applications. As of December 31, 2015, we discontinued our engineering, production, and sales of our inverter product line. As such, all inverter product revenues, costs, assets, and liabilities are reported in Discontinued Operations for all periods presented herein, and we currently report as a single unit. Ongoing inverter repair and service operations are reported as part of our continuing operations. In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments, consisting of normal, recurring adjustments, necessary to present fairly the financial position of the Company as of September 30, 2021, and the results of our operations and cash flows for the three and nine months ended September 30, 2021 and 2020. The unaudited 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 omitted pursuant to such rules and regulations. These unaudited 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 year ended December 31, 2020 and other financial information filed with the SEC. Use of Estimates in the Preparation of the Consolidated Financial Statements 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, the disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The significant estimates, assumptions, and judgments include, but are not limited to: ​ ● allowances for expected credit loss; ● excess and obsolete inventory; ● warranty reserves; ● pension obligations; ● right-of-use assets and related operating lease liabilities; ● acquisitions and asset valuations; ● asset lives; ● depreciation and amortization; ● recoverability of assets and potential impairment; ● deferred revenue; ● stock options, performance-based stock, and restricted stock grants; and ● taxes and other provisions. ​ We believe our significant estimates, assumptions, and judgments are reasonable based on the 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 Note 1 to our audited consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2020 . 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, will not have a material impact on the consolidated financial statements upon adoption. New Accounting Standards Adopted ​ 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 was effective for us on January 1, 2021. The impact of adoption was not material to our consolidated financial statements. New Accounting Standards Issued But Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting" "Reference Rate Reform (Topic 848): Scope"

ACQUISITIONS

ACQUISITIONS	9 Months Ended
	Sep. 30, 2021
ACQUISITIONS
ACQUISITIONS	NOTE 2. ACQUISITIONS Intangible Assets Acquired In January 2021, we acquired certain intangible assets related to the manufacturing of fiber optic sensing equipment for $3.6 million in cash and an additional $2.9 million expected to be paid within one year of the closing date. These intangible assets have an estimated useful life of five years. See Note 12. Intangible Assets TEGAM, Inc. On June 1, 2021, we acquired 100% of the issued and outstanding shares of capital stock of TEGAM, Inc., which is based in Geneva, Ohio. This acquisition added metrology and calibration instrumentation to Advanced Energy’s radio frequency (“RF”) process power solutions in our semiconductor and advanced industrial markets. The components of the fair value of the total consideration transferred were as follows: ​ ​ ​ ​ ​ Cash paid for acquisition $ 15,552 Holdback ​ ​ 2,100 Total fair value of consideration transferred ​ ​ 17,652 Less cash acquired ​ ​ (472) Total purchase price ​ $ 17,180 ​ We are still evaluating the fair value for the assets acquired and liabilities assumed. Accordingly, the purchase price allocation presented below is preliminary. ​ ​ ​ ​ ​ ​ Preliminary Current assets and liabilities, net ​ $ 3,870 Property and equipment ​ ​ 734 Operating lease right-of-use assets ​ ​ 425 Intangible assets ​ ​ 6,900 Goodwill ​ ​ 5,670 Other non-current assets ​ ​ 31 Total assets acquired ​ ​ 17,630 Other non-current liabilities ​ ​ 25 Operating lease liability ​ ​ 425 Total liabilities assumed ​ ​ 450 Total fair value of net assets acquired ​ $ 17,180 ​ Versatile Power, Inc. On December 31, 2020, we acquired 100% of the issued and outstanding shares of capital stock of Versatile Power, Inc., which is based in Campbell, California. This acquisition added RF and programmable power supplies for medical and industrial applications to our product portfolio and further expands our presence in the medical market by adding proven technologies, deep customer relationships, expertise in medical design, and a medical-certified manufacturing center. The components of the fair value of the total consideration transferred were as follows: ​ ​ ​ ​ ​ Cash paid for acquisition $ 4,654 Holdback ​ ​ 950 Contingent consideration ​ ​ 1,500 Total fair value of consideration transferred ​ ​ 7,104 Less cash acquired ​ ​ (245) Total purchase price ​ $ 6,859 ​ We are still evaluating the fair value for the assets acquired and liabilities assumed. Accordingly, the purchase price allocation presented below is preliminary. ​ ​ ​ ​ ​ ​ Preliminary Current assets and liabilities, net ​ $ 1,013 Property and equipment ​ ​ 35 Operating lease right-of-use assets ​ ​ 463 Intangible assets ​ ​ 4,000 Goodwill ​ ​ 1,831 Total assets acquired ​ ​ 7,342 Other non-current liabilities ​ ​ 20 Operating lease liability ​ ​ 463 Total liabilities assumed ​ ​ 483 Total fair value of net assets acquired ​ $ 6,859 ​

REVENUE

REVENUE	9 Months Ended
	Sep. 30, 2021
REVENUE
REVENUE	NOTE 3. REVENUE Revenue Recognition We recognize revenue when we have satisfied our performance obligations which typically occurs when control of the products or services has 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. 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. As a result of the Artesyn acquisition, we now sell precision power conversion products into the Telecom and Networking, Data Center Computing (including hyperscale), and Industrial and Medical 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, Telecom and Networking, Data Center Computing, Industrial and Medical markets. Our advanced power 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. Our embedded power products are used in a wide range of applications, such as 5G, data center (including hyperscale) and other industrial and medical applications. Services Our 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 in the United States ("U.S."), the People’s Republic of China ("PRC"), Japan, Korea, Taiwan, Germany, Ireland, Singapore, Israel, and Great Britain. Support services include warranty and non-warranty repair services, upgrades, and refurbishments on the products we sell. 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. The following table summarizes deferred revenue, which relates to extended warranties and service contracts. We expect to recognize this revenue ratably through the year 2031. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Deferred revenue ​ $ 7,908 ​ $ 8,671 ​ Disaggregation of Revenue The following tables present additional information regarding our revenue: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Semiconductor Equipment ​ $ 173,441 ​ $ 167,058 ​ $ 530,828 ​ $ 446,107 Industrial and Medical ​ 80,800 ​ 87,013 ​ 242,412 ​ 219,877 Data Center Computing ​ ​ 62,231 ​ ​ 87,741 ​ ​ 190,843 ​ ​ 257,240 Telecom and Networking ​ ​ 29,621 ​ ​ 47,709 ​ ​ 94,941 ​ ​ 121,633 Total ​ $ 346,093 ​ $ 389,521 ​ $ 1,059,024 ​ $ 1,044,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 ​ 2020 2021 2020 Product ​ $ 312,389 ​ $ 358,257 ​ $ 956,790 ​ $ 959,388 Services ​ ​ 33,704 ​ 31,264 ​ ​ 102,234 ​ 85,469 Total ​ $ 346,093 $ 389,521 ​ $ 1,059,024 $ 1,044,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 ​ 2020 2021 2020 United States ​ $ 139,089 ​ $ 152,503 ​ $ 410,212 ​ $ 389,007 North America (excluding U.S.) ​ ​ 24,708 ​ 38,126 ​ ​ 77,067 ​ 115,712 Asia ​ 135,838 ​ 180,660 ​ ​ 434,232 ​ 462,388 Europe ​ 44,838 ​ 17,886 ​ ​ 129,751 ​ 76,070 Other ​ 1,620 ​ 346 ​ ​ 7,762 ​ 1,680 Total ​ $ 346,093 $ 389,521 ​ $ 1,059,024 $ 1,044,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Product and service revenue recognized at point in time ​ $ 345,548 ​ $ 389,306 ​ $ 1,058,012 ​ $ 1,044,255 Extended warranty and service contracts recognized over time ​ 545 ​ 215 ​ 1,012 ​ 602 Total ​ $ 346,093 ​ $ 389,521 ​ $ 1,059,024 ​ $ 1,044,857 ​

INCOME TAXES

INCOME TAXES	9 Months Ended
	Sep. 30, 2021
INCOME TAXES
INCOME TAXES	NOTE 4. INCOME TAXES The following table summarizes tax expense and the effective tax rate for our income from continuing operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 2020 2021 2020 ​ Income from continuing operations, before income taxes ​ $ 24,704 ​ $ 52,396 ​ $ 105,797 ​ $ 108,583 ​ Provision for income taxes ​ $ 3,657 ​ $ 6,783 ​ $ 10,817 ​ $ 15,293 ​ Effective tax rate ​ ​ 14.8 % ​ 12.9 % ​ 10.2 % ​ 14.1 % ​ The Company’s effective tax rates differ from the U.S. federal statutory rate of 21% for the three and nine months ended September 30, 2021 and 2020, respectively, primarily due to the benefit of earnings in foreign jurisdictions which are subject to lower tax rates, partially offset by net U.S. tax on foreign operations and withholding taxes. The effective tax rate for the first nine months of 2021 was lower than the same period in 2020 primarily due to the mix of discrete events between the two periods.

EARNINGS PER SHARE

EARNINGS PER SHARE	9 Months Ended
	Sep. 30, 2021
EARNINGS PER SHARE
EARNINGS PER SHARE	NOTE 5. 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 earnings per share: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Income from continuing operations ​ $ 21,047 ​ $ 45,613 ​ $ 94,980 ​ $ 93,290 Income from continuing operations attributable to noncontrolling interest ​ 6 ​ 36 ​ 70 ​ 35 Income from continuing operations attributable to Advanced Energy Industries, Inc. ​ $ 21,041 ​ $ 45,577 ​ $ 94,910 ​ $ 93,255 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic weighted-average common shares outstanding ​ 38,183 ​ 38,325 ​ 38,296 ​ 38,322 Assumed exercise of dilutive stock options and restricted stock units ​ 180 ​ 203 ​ 221 ​ 209 Diluted weighted-average common shares outstanding ​ 38,363 ​ 38,528 ​ 38,517 ​ 38,531 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Continuing operations: ​ ​ ​ ​ Basic earnings per share ​ $ 0.55 ​ $ 1.19 ​ $ 2.48 ​ $ 2.43 Diluted earnings per share ​ $ 0.55 ​ $ 1.18 ​ $ 2.46 ​ $ 2.42 ​ The following stock awards were excluded in the computation of diluted earnings per share because they were anti-dilutive: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Restricted stock units 82 — 2 — ​ Share Repurchase To execute the repurchase of shares of our common stock, the Company periodically enters into stock repurchase agreements. The following table summarizes these repurchases: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, (in thousands, except per share amounts) 2021 2020 2021 2020 Amount paid and accrued to repurchase shares ​ $ 52,555 ​ $ 4,331 ​ $ 59,058 ​ $ 11,579 Number of shares repurchased ​ 605 ​ 73 ​ 677 ​ 243 Average repurchase price per share ​ $ 86.93 ​ $ 59.70 ​ $ 87.30 ​ $ 47.70 Remaining authorized by Board of Directors for future repurchases as of period end ​ $ 147,444 ​ $ 38,420 ​ $ 147,444 ​ $ 38,420 ​ There were no shares repurchased from related parties. Repurchased shares were retired and assumed the status of authorized and unissued shares. ​ On July 29, 2021, the Board of Directors approved an increase to the share repurchase program, which authorized the Company to repurchase up to $200 million in shares of our common stock with no time limitation. During the quarter, we repurchased 0.605 million shares of our common stock for $52.6 million. Subsequent to September 30, 2021 and before the filing date of this

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	9 Months Ended
	Sep. 30, 2021
FAIR VALUE MEASUREMENTS
FAIR VALUE MEASUREMENTS	NOTE 6. FAIR VALUE MEASUREMENTS The following tables present information about the Company’s assets and liabilities measured at fair value on a recurring basis. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 Description ​ Balance Sheet Classification ​ Level 1 ​ Level 2 ​ Level 3 ​ Total Value Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ Certificates of deposit ​ Marketable securities ​ $ — ​ $ 2,833 ​ $ — ​ $ 2,833 Foreign currency forward contracts ​ Other current assets ​ ​ — ​ ​ 38 ​ ​ — ​ ​ 38 Interest rate swaps ​ Deposits and other assets ​ ​ — ​ ​ 52 ​ ​ — ​ ​ 52 Total assets measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ 2,923 ​ $ — ​ $ 2,923 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ Other current liabilities ​ $ — ​ $ — ​ $ 2,169 ​ $ 2,169 Contingent consideration ​ Other long-term liabilities ​ ​ — ​ ​ — ​ ​ 3,052 ​ ​ 3,052 Total liabilities measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ — ​ $ 5,221 ​ $ 5,221 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 Description ​ Balance Sheet Classification ​ Level 1 Level 2 Level 3 Total Value Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ Certificates of deposit ​ Marketable securities ​ $ — ​ $ 2,654 ​ $ — ​ $ 2,654 Total assets measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ 2,654 ​ $ — ​ $ 2,654 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ Other current liabilities ​ $ — ​ $ — ​ $ 2,009 ​ $ 2,009 Contingent consideration ​ Other long-term liabilities ​ ​ — ​ ​ — ​ ​ 2,940 ​ ​ 2,940 Interest rate swaps ​ Other long-term liabilities ​ ​ — ​ ​ 2,811 ​ ​ — ​ ​ 2,811 Total liabilities measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ 2,811 ​ $ 4,949 ​ $ 7,760 ​ The fair value of foreign currency forward contracts is based on the movement in the forward rates of foreign currency cash flows in which the hedging instrument is denominated. We determine the fair value of interest rate swaps by estimating the net present value of the expected cash flows based on market rates and associated yield curves, adjusted for non-performance credit risk, as applicable. See Note 7. Derivative Financial Instruments

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS	9 Months Ended
	Sep. 30, 2021
DERIVATIVE FINANCIAL INSTRUMENTS
DERIVATIVE FINANCIAL INSTRUMENTS	NOTE 7. 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. These forward contracts manage the exchange rate risk associated with assets and liabilities denominated in nonfunctional currencies. These derivative instruments are typically executed for one-month periods and not designated as hedges; however, they do economically offset the fluctuations of our assets and liabilities due to foreign exchange rate changes. The following table summarizes the notional amount of outstanding foreign currency forward contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Foreign currency forward contracts ​ $ 45,550 ​ $ — ​ Gains and losses related to foreign currency exchange contracts were offset by corresponding gains and losses on the revaluation of the underlying assets and liabilities. Both are included as a component of other income (expense), net in our Unaudited Consolidated Statements of Operations. In April 2020, the Company executed interest rate swap contracts with independent financial institutions to partially reduce the variability of cash flows in LIBOR indexed debt interest payments on our Term Loan Facility (under the Company’s existing Credit Agreement dated September 10, 2019). These transactions are accounted for as cash flow hedging instruments. The interest rate swap contracts fixed a portion of the outstanding principal balance on our term loan to a total interest rate of 1.271%. This is comprised of 0.521% average fixed rate per annum in exchange for a variable interest rate based on one-month USD-LIBOR-BBA plus the credit spread in the Company’s existing Credit Agreement, which is 75 basis points at current leverage ratios. The following table summarizes the notional amount of qualified hedging instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Interest rate swap contracts ​ $ 260,094 ​ $ 273,219 ​ The following table summarizes the balances recorded in Accumulated other comprehensive loss on the Unaudited Consolidated Balance Sheets for qualifying hedges. ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Interest rate swap contracts ​ $ (40) ​ $ 2,139 ​ See Note 6. Fair Value Measurements As a result of the use of derivative financial instruments, the Company is exposed to the risk that counterparties to derivative contracts may fail to meet their contractual obligations. The Company manages counterparty credit risk in derivative contracts by reviewing counterparty creditworthiness on a regular basis and limiting exposure to any single counterparty.

ACCOUNTS AND OTHER RECEIVABLE,

ACCOUNTS AND OTHER RECEIVABLE, NET	9 Months Ended
	Sep. 30, 2021
ACCOUNTS AND OTHER RECEIVABLE, NET
ACCOUNTS AND OTHER RECEIVABLE, NET	NOTE 8. ACCOUNTS AND OTHER RECEIVABLE, NET Accounts and other receivable are recorded at net realizable value. Components of accounts and other receivable, net of reserves, were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Amounts billed, net ​ $ 192,147 ​ $ 213,560 Unbilled receivables ​ ​ 27,965 ​ 21,618 Total receivables, net ​ $ 220,112 ​ $ 235,178 ​ Amounts billed, net consist of amounts that have been invoiced to our customers in accordance with terms and conditions and are shown net of an allowance for credit losses. These receivables are all short-term in nature and do not include any financing components. 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. These contracts do not include any financing components. ​ The following table summarizes the changes in expected credit losses: ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ September 30, 2021 Balance at beginning of period $ 7,602 Additions ​ - Deductions - write-offs, net of recoveries ​ (677) Foreign currency translation ​ ​ (22) Other ​ ​ (1,248) Balance at end of period ​ $ 5,655 ​

INVENTORIES

INVENTORIES	9 Months Ended
	Sep. 30, 2021
INVENTORIES
INVENTORIES	NOTE 9. 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 were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Parts and raw materials ​ $ 258,281 ​ $ 141,337 Work in process ​ 21,569 ​ 13,702 Finished goods ​ 61,650 ​ 66,307 Total ​ $ 341,500 ​ $ 221,346 ​

PROPERTY AND EQUIPMENT, NET

PROPERTY AND EQUIPMENT, NET	9 Months Ended
	Sep. 30, 2021
PROPERTY AND EQUIPMENT, NET
PROPERTY AND EQUIPMENT, NET	NOTE 10. PROPERTY AND EQUIPMENT, NET Property and equipment, net is comprised of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Buildings and land ​ $ 1,631 ​ $ 1,776 Machinery and equipment ​ 126,896 ​ 115,404 Computer and communication equipment ​ 27,589 ​ 26,623 Furniture and fixtures ​ 5,055 ​ 4,352 Vehicles ​ 261 ​ 262 Leasehold improvements ​ 46,345 ​ 42,984 Construction in process ​ 5,017 ​ 3,693 ​ ​ 212,794 ​ 195,094 Less: Accumulated depreciation ​ (97,993) ​ (80,363) Property and equipment, net ​ $ 114,801 ​ $ 114,731 ​ The following table summarizes depreciation expense. All depreciation expense is recorded in income from continuing operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Depreciation expense ​ $ 7,874 ​ $ 7,188 ​ $ 22,721 ​ $ 20,369 ​

GOODWILL

GOODWILL	9 Months Ended
	Sep. 30, 2021
GOODWILL AND INTANGIBLE ASSETS
GOODWILL	NOTE 11. GOODWILL The following table summarizes the changes in goodwill: ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ September 30, 2021 Balance at beginning of period $ 209,983 Measurement period adjustments to purchase price allocation ​ ​ 82 Additions from acquisition ​ ​ 5,670 Foreign currency translation ​ ​ (2,110) Balance at end of period ​ $ 213,625 ​

INTANGIBLE ASSETS

INTANGIBLE ASSETS	9 Months Ended
	Sep. 30, 2021
GOODWILL AND INTANGIBLE ASSETS
INTANGIBLE ASSETS	NOTE 12. INTANGIBLE ASSETS Intangible assets consisted of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ Gross Carrying Accumulated Net Carrying ​ ​ Amount ​ Amortization ​ Amount Technology ​ $ 91,605 ​ $ (33,055) ​ $ 58,550 Customer relationships ​ 118,733 ​ ​ (32,182) ​ 86,551 Trademarks and other ​ 27,249 ​ ​ (7,318) ​ 19,931 Total ​ $ 237,587 ​ $ (72,555) ​ $ 165,032 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Gross Carrying Accumulated Net Carrying ​ ​ Amount ​ Amortization ​ Amount Technology ​ $ 85,075 ​ $ (24,999) ​ $ 60,076 Customer relationships ​ 114,171 ​ (26,880) ​ 87,291 Trademarks and other ​ 27,021 ​ (5,449) ​ 21,572 Total ​ $ 226,267 ​ $ (57,328) ​ $ 168,939 ​ Amortization expense related to intangible assets is as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Amortization expense ​ $ 5,607 ​ $ 5,049 ​ $ 16,504 ​ $ 15,064 ​ Estimated amortization expense related to intangibles is as follows: ​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2021 (remaining) ​ $ 5,541 2022 ​ 22,043 2023 ​ 22,024 2024 ​ 19,153 2025 ​ 14,665 Thereafter ​ 81,606 Total ​ $ 165,032 ​

RESTRUCTURING COSTS

RESTRUCTURING COSTS	9 Months Ended
	Sep. 30, 2021
RESTRUCTURING COSTS
RESTRUCTURING COSTS	NOTE 13. 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. For the periods presented, we incurred severance costs primarily related to the transition and exit of our facility in Shenzhen, PRC and actions associated with synergies related to the Artesyn acquisition. The table below summarizes the restructuring charges: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 Severance and related charges $ 676 $ 202 $ 1,270 $ 5,207 Facility relocation and closure charges ​ ​ 596 ​ 1,292 ​ 1,251 ​ 2,733 Total restructuring charges ​ $ 1,272 $ 1,494 $ 2,521 $ 7,940 ​ ​ ​ ​ ​ ​ ​ Cumulative Cost ​ ​ Through ​ ​ September 30, ​ ​ 2021 Severance and related charges $ 18,183 Facility relocation and closure charges ​ ​ 6,781 Total restructuring charges ​ $ 24,964 ​ Our restructuring liabilities are included in other accrued expenses in our Unaudited Consolidated Balance Sheets and related primarily to severance and related charges. Changes in restructuring liabilities were as follows: ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ September 30, 2021 Balance at beginning of period $ 10,641 Costs incurred and charged to expense ​ ​ 2,521 Costs paid or otherwise settled ​ ​ (3,463) Effects of changes in exchange rate ​ ​ — Balance at end of period ​ $ 9,699 ​

WARRANTIES

WARRANTIES	9 Months Ended
	Sep. 30, 2021
WARRANTIES
WARRANTIES	NOTE 14. WARRANTIES Provisions of our sales agreements include customary product warranties, generally ranging from 12 months to 24 months after shipment. The estimated cost of our warranty obligation is recorded when revenue is recognized and is based upon our historical experience by product and configuration. Our estimated warranty obligation is included in other accrued expenses in our Unaudited Consolidated Balance Sheets. Changes in our product warranty obligation were as follows: ​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ September 30, 2021 Balance at beginning of period ​ $ 4,780 Increases to accruals ​ 2,290 Warranty expenditures ​ (3,404) Effect of changes in exchange rates ​ (4) Balance at end of period ​ $ 3,662 ​

LEASES

LEASES	9 Months Ended
	Sep. 30, 2021
LEASES
LEASES	NOTE 15. LEASES The Company leases manufacturing and office space under non-cancelable operating leases. Some of these leases contain provisions for landlord funded leasehold improvements which are recorded as a reduction to right-of-use ("ROU") assets and the related operating lease liabilities. For leases containing an option 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 ROU assets and operating 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 operating lease liabilities. New leases are negotiated and executed to meet business objectives on an on-going basis. 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, we apply a portfolio approach for determining the incremental borrowing rate applicable to the lease term. Components of operating lease cost were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Operating lease cost ​ $ 5,735 ​ $ 4,806 ​ $ 17,708 ​ $ 14,500 Short-term and variable lease cost ​ ​ 578 ​ ​ 1,504 ​ ​ 1,704 ​ ​ 4,151 Total operating lease cost ​ $ 6,313 ​ $ 6,310 ​ $ 19,412 ​ $ 18,651 ​ Maturities of our operating lease liabilities are as follows: ​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2021 (remaining) ​ $ 5,507 2022 ​ 20,004 2023 ​ 16,685 2024 ​ 14,295 2025 ​ ​ 12,027 Thereafter ​ ​ 75,473 Total lease payments ​ ​ 143,991 Less: Interest ​ ​ (31,517) Present value of lease liabilities ​ $ 112,474 ​ In addition, we have lease agreements that commence in the future between 2021 and 2023 with total payments of $3.9 million through 2028. Other information related to leases, including supplemental cash flow information, consists of: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ ​ December 31, ​ ​ 2021 2020 ​ Weighted average remaining lease term (in years) ​ ​ 9.91 ​ ​ ​ 10.65 ​ Weighted average discount rate ​ 4.51 % ​ ​ 4.63 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 2020 2021 2020 ​ Cash paid for operating leases $ 6,058 ​ $ 5,934 ​ $ 18,037 ​ $ 17,336 ​ Right-of-use assets obtained in exchange for operating lease liabilities $ 7,169 ​ $ 9,586 ​ $ 14,402 ​ $ 34,064 ​ ​

STOCK-BASED COMPENSATION

STOCK-BASED COMPENSATION	9 Months Ended
	Sep. 30, 2021
STOCK-BASED COMPENSATION
STOCK-BASED COMPENSATION	NOTE 16. STOCK-BASED COMPENSATION On May 4, 2017, the stockholders 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 and 2008 Plan provide 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 may be issued as performance-based awards to align stock compensation awards to the attainment of annual or long-term performance goals. As of September 30, 2021, there were 1.9 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 on the date of grant and with generally a three ​ Stock option awards are generally granted with an exercise price equal to the market price of our stock on the date of grant and with either a three ​ 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 was as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Stock-based compensation expense ​ $ 3,674 ​ $ 3,781 ​ $ 12,819 ​ $ 9,666 ​ Changes in our RSUs were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2021 ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ RSUs ​ Fair Value RSUs outstanding at beginning of period 608 ​ $ 58.15 RSUs granted 388 ​ $ 95.96 RSUs vested (177) ​ $ 62.73 RSUs forfeited (182) ​ $ 68.49 RSUs outstanding at end of period 637 ​ $ 76.97 ​ Changes in our stock options were as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2021 ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Exercise Price ​ ​ Options ​ per Share Options outstanding at beginning of period 147 ​ $ 23.63 Options exercised (35) ​ $ 21.10 Options expired — ​ $ — Options outstanding at end of period 112 ​ $ 24.41 ​

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	9 Months Ended
	Sep. 30, 2021
COMMITMENTS AND CONTINGENCIES
COMMITMENTS AND CONTINGENCIES	NOTE 17. COMMITMENTS AND CONTINGENCIES We are involved in disputes and legal actions arising in the normal course of our business. While we currently believe that the amount of any ultimate loss would not be material to our financial position, the outcome of these actions is inherently difficult to predict. In the event of an adverse outcome, the ultimate loss could have a material adverse effect on our financial position or reported results of operations. An unfavorable decision in patent litigation also could require material changes in production processes and products or result in our inability to ship products or components found to have violated third-party patent rights. We accrue loss contingencies in connection with our commitments and contingencies, including litigation, when it is probable that a loss has occurred, and the amount of the loss can be reasonably estimated. The Company is not currently party to any legal action that the Company believes would reasonably have a material adverse impact on its business, financial condition, results of operations or cash flows.

SIGNIFICANT CUSTOMER INFORMATIO

SIGNIFICANT CUSTOMER INFORMATION	9 Months Ended
	Sep. 30, 2021
SIGNIFICANT CUSTOMER INFORMATION
SIGNIFICANT CUSTOMER INFORMATION	NOTE 18. SIGNIFICANT CUSTOMER INFORMATION The following table summarizes sales, and percentages of sales, by customers that individually accounted for 10% or more of our sales: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ Applied Materials, Inc. ​ $ 77,136 22.3 % $ 65,740 16.9 % Lam Research ​ $ 39,149 11.3 % ​ ​ 40,798 10.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ Applied Materials, Inc. ​ $ 218,757 20.7 % $ 181,129 17.3 % Lam Research ​ $ 109,734 10.4 % ​ ​ * * % ​ 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: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ ​ 2020 ​ Applied Materials, Inc. ​ $ 41,159 18.7 % $ 33,402 14.2 % Nidec Motor Corporation ​ ​ * ​ * % $ 24,344 ​ 10.4 % ​ * Customer’s balance was less than 10% of total. ​ Our sales to Applied Materials, Inc. and Lam Research include precision power products used in semiconductor processing and solar and flat panel display. Our sales to Nidec Motor Corporation are primarily embedded power products used in industrial motor drives. No other customer accounted for 10% or more of our sales or accounts receivable balances during these periods.

CREDIT FACILITY

CREDIT FACILITY	9 Months Ended
	Sep. 30, 2021
CREDIT FACILITY
CREDIT FACILITY	NOTE 19. CREDIT FACILITY In September 2019, in connection with the Artesyn Acquisition Agreement, we entered into a credit agreement ("Credit Agreement") that provided aggregate financing of $500.0 million, consisting of a $350.0 million senior unsecured term loan facility (the "Term Loan Facility") and a $150.0 million senior unsecured revolving facility (the "Revolving Facility" and together with the Term Loan Facility, the "Credit Facility"). In September 2021, we amended the Credit Agreement whereby we borrowed an additional $85.0 million, which increased the aggregate amount outstanding under the Term Loan Facility to $400.0 million. In addition, we increased the Revolving Facility capacity by $50.0 million to $200.0 million. Both the Term Loan Facility and Revolving Facility mature on September 9, 2026. The following table summarizes borrowings under our Credit Facility and the associated interest rate. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ Balance Interest Rate Unused Line Fee Term Loan Facility subject to a fixed interest rate ​ $ 260,094 ​ 1.271% ​ - Term Loan Facility subject to a variable interest rate ​ ​ 139,906 ​ 0.890% ​ - Revolving Facility subject to a variable interest rate ​ ​ — ​ 0.890% ​ 0.10% Total borrowings under the Credit Agreement ​ $ 400,000 ​ ​ ​ ​ ​ For more information on the interest rate swap that fixes the interest rate for a portion of our Term Loan Facility, see Note 7. Derivative Financial Instruments For all periods presented, we were in compliance with the Credit Agreement covenants. As of September 30, 2021 and December 31, 2020, we had $200.0 million and $150.0 million, respectively, available to withdraw on the Revolving Facility. We classify the Credit Facility in Level 2 of the fair value hierarchy. The fair value approximates the outstanding balance of $400.0 million as of September 30, 2021. The debt obligation on our Unaudited Consolidated Balance Sheets consists of the following: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Term Loan Facility ​ $ 400,000 ​ $ 323,750 Less: debt issuance costs ​ ​ (2,403) ​ ​ (1,704) Total debt ​ ​ 397,597 ​ ​ 322,046 Less current portion of long-term debt ​ ​ (20,000) ​ ​ (17,500) Total long-term debt ​ $ 377,597 ​ $ 304,546 ​ Contractual maturities of the Company’s debt obligations, excluding amortization of debt issuance costs, are as follows: ​ ​ ​ ​ ​ Year Ending December 31, ​ 2021 (remaining) ​ $ 5,000 2022 ​ ​ 20,000 2023 ​ ​ 20,000 2024 ​ ​ 20,000 2025 ​ ​ 20,000 Thereafter ​ ​ 315,000 Total ​ $ 400,000 ​ Interest expense and unused line of credit fees were recorded in other income (expense), net in our Unaudited Consolidated Statements of Operations as follows: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Interest expense ​ $ 1,009 ​ $ 778 ​ $ 2,973 ​ $ 4,021 Amortization of debt issuance costs ​ ​ 420 ​ ​ 129 ​ ​ 669 ​ ​ 392 Unused line of credit fees and other ​ ​ 41 ​ ​ 38 ​ ​ 116 ​ ​ 114 Total interest expense ​ $ 1,470 ​ $ 945 ​ $ 3,758 ​ $ 4,527 ​

DESCRIPTION OF BUSINESS AND B_2

DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION (Policies)	9 Months Ended
	Sep. 30, 2021
DESCRIPTION OF BUSINESS AND BASIS OF PRESENTATION
Use of Estimates in the Preparation of the Consolidated Financial Statements	Use of Estimates in the Preparation of the Consolidated Financial Statements 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, the disclosure of contingent liabilities at the date of the financial statements and the reported amounts of revenue and expenses during the reporting period. The significant estimates, assumptions, and judgments include, but are not limited to: ​ ● allowances for expected credit loss; ● excess and obsolete inventory; ● warranty reserves; ● pension obligations; ● right-of-use assets and related operating lease liabilities; ● acquisitions and asset valuations; ● asset lives; ● depreciation and amortization; ● recoverability of assets and potential impairment; ● deferred revenue; ● stock options, performance-based stock, and restricted stock grants; and ● taxes and other provisions. ​ We believe our significant estimates, assumptions, and judgments are reasonable based on the 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	Critical Accounting Policies Our accounting policies are described in Note 1 to our audited consolidated financial statements in our Annual Report on Form 10-K for the year ended December 31, 2020 .
New Accounting Standards	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, will not have a material impact on the consolidated financial statements upon adoption. New Accounting Standards Adopted ​ 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 was effective for us on January 1, 2021. The impact of adoption was not material to our consolidated financial statements. New Accounting Standards Issued But Not Yet Adopted In March 2020, the FASB issued ASU 2020-04, "Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting" "Reference Rate Reform (Topic 848): Scope"

ACQUISITIONS (Tables)

ACQUISITIONS (Tables)	9 Months Ended
	Sep. 30, 2021
TEGAM, Inc. [Member]
Business Acquisition [Line Items]
Schedule of components of fair value of total consideration transferred	​ ​ ​ ​ ​ Cash paid for acquisition $ 15,552 Holdback ​ ​ 2,100 Total fair value of consideration transferred ​ ​ 17,652 Less cash acquired ​ ​ (472) Total purchase price ​ $ 17,180
Schedule of fair value of assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ Preliminary Current assets and liabilities, net ​ $ 3,870 Property and equipment ​ ​ 734 Operating lease right-of-use assets ​ ​ 425 Intangible assets ​ ​ 6,900 Goodwill ​ ​ 5,670 Other non-current assets ​ ​ 31 Total assets acquired ​ ​ 17,630 Other non-current liabilities ​ ​ 25 Operating lease liability ​ ​ 425 Total liabilities assumed ​ ​ 450 Total fair value of net assets acquired ​ $ 17,180
Versatile Power Inc [Member]
Business Acquisition [Line Items]
Schedule of components of fair value of total consideration transferred	​ ​ ​ ​ ​ Cash paid for acquisition $ 4,654 Holdback ​ ​ 950 Contingent consideration ​ ​ 1,500 Total fair value of consideration transferred ​ ​ 7,104 Less cash acquired ​ ​ (245) Total purchase price ​ $ 6,859
Schedule of fair value of assets acquired and liabilities assumed	​ ​ ​ ​ ​ ​ Preliminary Current assets and liabilities, net ​ $ 1,013 Property and equipment ​ ​ 35 Operating lease right-of-use assets ​ ​ 463 Intangible assets ​ ​ 4,000 Goodwill ​ ​ 1,831 Total assets acquired ​ ​ 7,342 Other non-current liabilities ​ ​ 20 Operating lease liability ​ ​ 463 Total liabilities assumed ​ ​ 483 Total fair value of net assets acquired ​ $ 6,859

REVENUE (Tables)

REVENUE (Tables)	9 Months Ended
	Sep. 30, 2021
REVENUE
Summary of deferred revenue,	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Deferred revenue ​ $ 7,908 ​ $ 8,671
Schedule of disaggregation of revenue	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Semiconductor Equipment ​ $ 173,441 ​ $ 167,058 ​ $ 530,828 ​ $ 446,107 Industrial and Medical ​ 80,800 ​ 87,013 ​ 242,412 ​ 219,877 Data Center Computing ​ ​ 62,231 ​ ​ 87,741 ​ ​ 190,843 ​ ​ 257,240 Telecom and Networking ​ ​ 29,621 ​ ​ 47,709 ​ ​ 94,941 ​ ​ 121,633 Total ​ $ 346,093 ​ $ 389,521 ​ $ 1,059,024 ​ $ 1,044,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 ​ 2020 2021 2020 Product ​ $ 312,389 ​ $ 358,257 ​ $ 956,790 ​ $ 959,388 Services ​ ​ 33,704 ​ 31,264 ​ ​ 102,234 ​ 85,469 Total ​ $ 346,093 $ 389,521 ​ $ 1,059,024 $ 1,044,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 ​ 2020 2021 2020 United States ​ $ 139,089 ​ $ 152,503 ​ $ 410,212 ​ $ 389,007 North America (excluding U.S.) ​ ​ 24,708 ​ 38,126 ​ ​ 77,067 ​ 115,712 Asia ​ 135,838 ​ 180,660 ​ ​ 434,232 ​ 462,388 Europe ​ 44,838 ​ 17,886 ​ ​ 129,751 ​ 76,070 Other ​ 1,620 ​ 346 ​ ​ 7,762 ​ 1,680 Total ​ $ 346,093 $ 389,521 ​ $ 1,059,024 $ 1,044,857 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Product and service revenue recognized at point in time ​ $ 345,548 ​ $ 389,306 ​ $ 1,058,012 ​ $ 1,044,255 Extended warranty and service contracts recognized over time ​ 545 ​ 215 ​ 1,012 ​ 602 Total ​ $ 346,093 ​ $ 389,521 ​ $ 1,059,024 ​ $ 1,044,857

INCOME TAXES (Tables)

INCOME TAXES (Tables)	9 Months Ended
	Sep. 30, 2021
INCOME TAXES
Schedule of tax expense and the effective tax rate for income from continuing operations	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 2020 2021 2020 ​ Income from continuing operations, before income taxes ​ $ 24,704 ​ $ 52,396 ​ $ 105,797 ​ $ 108,583 ​ Provision for income taxes ​ $ 3,657 ​ $ 6,783 ​ $ 10,817 ​ $ 15,293 ​ Effective tax rate ​ ​ 14.8 % ​ 12.9 % ​ 10.2 % ​ 14.1 %

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2021
EARNINGS PER SHARE
Reconciliation of weighted-average shares outstanding used in calculation of basic and diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Income from continuing operations ​ $ 21,047 ​ $ 45,613 ​ $ 94,980 ​ $ 93,290 Income from continuing operations attributable to noncontrolling interest ​ 6 ​ 36 ​ 70 ​ 35 Income from continuing operations attributable to Advanced Energy Industries, Inc. ​ $ 21,041 ​ $ 45,577 ​ $ 94,910 ​ $ 93,255 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Basic weighted-average common shares outstanding ​ 38,183 ​ 38,325 ​ 38,296 ​ 38,322 Assumed exercise of dilutive stock options and restricted stock units ​ 180 ​ 203 ​ 221 ​ 209 Diluted weighted-average common shares outstanding ​ 38,363 ​ 38,528 ​ 38,517 ​ 38,531 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Continuing operations: ​ ​ ​ ​ Basic earnings per share ​ $ 0.55 ​ $ 1.19 ​ $ 2.48 ​ $ 2.43 Diluted earnings per share ​ $ 0.55 ​ $ 1.18 ​ $ 2.46 ​ $ 2.42
Schedule of stock options and restricted units excluded in computation of diluted EPS	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Restricted stock units 82 — 2 —
Schedule of repurchase of shares of common stock	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, (in thousands, except per share amounts) 2021 2020 2021 2020 Amount paid and accrued to repurchase shares ​ $ 52,555 ​ $ 4,331 ​ $ 59,058 ​ $ 11,579 Number of shares repurchased ​ 605 ​ 73 ​ 677 ​ 243 Average repurchase price per share ​ $ 86.93 ​ $ 59.70 ​ $ 87.30 ​ $ 47.70 Remaining authorized by Board of Directors for future repurchases as of period end ​ $ 147,444 ​ $ 38,420 ​ $ 147,444 ​ $ 38,420

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2021
FAIR VALUE MEASUREMENTS
Schedule of assets and liabilities measured at fair value on a recurring basis	The following tables present information about the Company’s assets and liabilities measured at fair value on a recurring basis. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 Description ​ Balance Sheet Classification ​ Level 1 ​ Level 2 ​ Level 3 ​ Total Value Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ Certificates of deposit ​ Marketable securities ​ $ — ​ $ 2,833 ​ $ — ​ $ 2,833 Foreign currency forward contracts ​ Other current assets ​ ​ — ​ ​ 38 ​ ​ — ​ ​ 38 Interest rate swaps ​ Deposits and other assets ​ ​ — ​ ​ 52 ​ ​ — ​ ​ 52 Total assets measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ 2,923 ​ $ — ​ $ 2,923 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ Other current liabilities ​ $ — ​ $ — ​ $ 2,169 ​ $ 2,169 Contingent consideration ​ Other long-term liabilities ​ ​ — ​ ​ — ​ ​ 3,052 ​ ​ 3,052 Total liabilities measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ — ​ $ 5,221 ​ $ 5,221 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 Description ​ Balance Sheet Classification ​ Level 1 Level 2 Level 3 Total Value Assets: ​ ​ ​ ​ ​ ​ ​ ​ ​ Certificates of deposit ​ Marketable securities ​ $ — ​ $ 2,654 ​ $ — ​ $ 2,654 Total assets measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ 2,654 ​ $ — ​ $ 2,654 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Liabilities: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Contingent consideration ​ Other current liabilities ​ $ — ​ $ — ​ $ 2,009 ​ $ 2,009 Contingent consideration ​ Other long-term liabilities ​ ​ — ​ ​ — ​ ​ 2,940 ​ ​ 2,940 Interest rate swaps ​ Other long-term liabilities ​ ​ — ​ ​ 2,811 ​ ​ — ​ ​ 2,811 Total liabilities measured at fair value on a recurring basis ​ ​ ​ $ — ​ $ 2,811 ​ $ 4,949 ​ $ 7,760

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS (Tables)	9 Months Ended
	Sep. 30, 2021
DERIVATIVE FINANCIAL INSTRUMENTS
Schedule of notional amount of outstanding foreign currency forward contracts	The following table summarizes the notional amount of outstanding foreign currency forward contracts: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Foreign currency forward contracts ​ $ 45,550 ​ $ — ​
Schedule of notional amount of qualified hedging instruments	The following table summarizes the notional amount of qualified hedging instruments: ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Interest rate swap contracts ​ $ 260,094 ​ $ 273,219
Schedule of balances recorded in Accumulated other comprehensive loss	The following table summarizes the balances recorded in Accumulated other comprehensive loss on the Unaudited Consolidated Balance Sheets for qualifying hedges. ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Interest rate swap contracts ​ $ (40) ​ $ 2,139

ACCOUNTS AND OTHER RECEIVABLE_2

ACCOUNTS AND OTHER RECEIVABLE, NET (Tables)	9 Months Ended
	Sep. 30, 2021
ACCOUNTS AND OTHER RECEIVABLE, NET
Schedule of accounts and other receivable	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Amounts billed, net ​ $ 192,147 ​ $ 213,560 Unbilled receivables ​ ​ 27,965 ​ 21,618 Total receivables, net ​ $ 220,112 ​ $ 235,178
Schedule of expected credit losses	​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ September 30, 2021 Balance at beginning of period $ 7,602 Additions ​ - Deductions - write-offs, net of recoveries ​ (677) Foreign currency translation ​ ​ (22) Other ​ ​ (1,248) Balance at end of period ​ $ 5,655

INVENTORIES (Tables)

INVENTORIES (Tables)	9 Months Ended
	Sep. 30, 2021
INVENTORIES
Schedule of components of inventories	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Parts and raw materials ​ $ 258,281 ​ $ 141,337 Work in process ​ 21,569 ​ 13,702 Finished goods ​ 61,650 ​ 66,307 Total ​ $ 341,500 ​ $ 221,346

PROPERTY AND EQUIPMENT, NET (Ta

PROPERTY AND EQUIPMENT, NET (Tables)	9 Months Ended
	Sep. 30, 2021
PROPERTY AND EQUIPMENT, NET
Schedule of property and equipment, net	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Buildings and land ​ $ 1,631 ​ $ 1,776 Machinery and equipment ​ 126,896 ​ 115,404 Computer and communication equipment ​ 27,589 ​ 26,623 Furniture and fixtures ​ 5,055 ​ 4,352 Vehicles ​ 261 ​ 262 Leasehold improvements ​ 46,345 ​ 42,984 Construction in process ​ 5,017 ​ 3,693 ​ ​ 212,794 ​ 195,094 Less: Accumulated depreciation ​ (97,993) ​ (80,363) Property and equipment, net ​ $ 114,801 ​ $ 114,731
Schedule of depreciation expense recorded in continuing operations	The following table summarizes depreciation expense. All depreciation expense is recorded in income from continuing operations: ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Depreciation expense ​ $ 7,874 ​ $ 7,188 ​ $ 22,721 ​ $ 20,369

GOODWILL (Tables)

GOODWILL (Tables)	9 Months Ended
	Sep. 30, 2021
GOODWILL AND INTANGIBLE ASSETS
Schedule of changes in goodwill	​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ ​ September 30, 2021 Balance at beginning of period $ 209,983 Measurement period adjustments to purchase price allocation ​ ​ 82 Additions from acquisition ​ ​ 5,670 Foreign currency translation ​ ​ (2,110) Balance at end of period ​ $ 213,625

INTANGIBLE ASSETS (Tables)

INTANGIBLE ASSETS (Tables)	9 Months Ended
	Sep. 30, 2021
GOODWILL AND INTANGIBLE ASSETS
Schedule of intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ Gross Carrying Accumulated Net Carrying ​ ​ Amount ​ Amortization ​ Amount Technology ​ $ 91,605 ​ $ (33,055) ​ $ 58,550 Customer relationships ​ 118,733 ​ ​ (32,182) ​ 86,551 Trademarks and other ​ 27,249 ​ ​ (7,318) ​ 19,931 Total ​ $ 237,587 ​ $ (72,555) ​ $ 165,032 ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ December 31, 2020 ​ Gross Carrying Accumulated Net Carrying ​ ​ Amount ​ Amortization ​ Amount Technology ​ $ 85,075 ​ $ (24,999) ​ $ 60,076 Customer relationships ​ 114,171 ​ (26,880) ​ 87,291 Trademarks and other ​ 27,021 ​ (5,449) ​ 21,572 Total ​ $ 226,267 ​ $ (57,328) ​ $ 168,939
Schedule of amortization expense related to intangible assets	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Amortization expense ​ $ 5,607 ​ $ 5,049 ​ $ 16,504 ​ $ 15,064
Schedule of estimated amortization expense related to intangible assets	​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2021 (remaining) ​ $ 5,541 2022 ​ 22,043 2023 ​ 22,024 2024 ​ 19,153 2025 ​ 14,665 Thereafter ​ 81,606 Total ​ $ 165,032

RESTRUCTURING COSTS (Tables)

RESTRUCTURING COSTS (Tables)	9 Months Ended
	Sep. 30, 2021
RESTRUCTURING COSTS
Schedule of restructuring charges	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 ​ 2020 ​ 2021 ​ 2020 Severance and related charges $ 676 $ 202 $ 1,270 $ 5,207 Facility relocation and closure charges ​ ​ 596 ​ 1,292 ​ 1,251 ​ 2,733 Total restructuring charges ​ $ 1,272 $ 1,494 $ 2,521 $ 7,940 ​ ​ ​ ​ ​ ​ ​ Cumulative Cost ​ ​ Through ​ ​ September 30, ​ ​ 2021 Severance and related charges $ 18,183 Facility relocation and closure charges ​ ​ 6,781 Total restructuring charges ​ $ 24,964
Schedule of restructuring liabilities	​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ September 30, 2021 Balance at beginning of period $ 10,641 Costs incurred and charged to expense ​ ​ 2,521 Costs paid or otherwise settled ​ ​ (3,463) Effects of changes in exchange rate ​ ​ — Balance at end of period ​ $ 9,699

WARRANTIES (Tables)

WARRANTIES (Tables)	9 Months Ended
	Sep. 30, 2021
WARRANTIES
Schedule of changes in accrued product warranties	​ ​ ​ ​ ​ ​ ​ Nine Months Ended ​ September 30, 2021 Balance at beginning of period ​ $ 4,780 Increases to accruals ​ 2,290 Warranty expenditures ​ (3,404) Effect of changes in exchange rates ​ (4) Balance at end of period ​ $ 3,662

LEASES (Tables)

LEASES (Tables)	9 Months Ended
	Sep. 30, 2021
LEASES
Components of operating lease cost	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Operating lease cost ​ $ 5,735 ​ $ 4,806 ​ $ 17,708 ​ $ 14,500 Short-term and variable lease cost ​ ​ 578 ​ ​ 1,504 ​ ​ 1,704 ​ ​ 4,151 Total operating lease cost ​ $ 6,313 ​ $ 6,310 ​ $ 19,412 ​ $ 18,651
Schedule of maturities of operating lease liabilities	​ ​ ​ ​ ​ Year Ending December 31, ​ ​ 2021 (remaining) ​ $ 5,507 2022 ​ 20,004 2023 ​ 16,685 2024 ​ 14,295 2025 ​ ​ 12,027 Thereafter ​ ​ 75,473 Total lease payments ​ ​ 143,991 Less: Interest ​ ​ (31,517) Present value of lease liabilities ​ $ 112,474
Schedule of other information related to leases	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ ​ December 31, ​ ​ 2021 2020 ​ Weighted average remaining lease term (in years) ​ ​ 9.91 ​ ​ ​ 10.65 ​ Weighted average discount rate ​ 4.51 % ​ ​ 4.63 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ ​ 2021 2020 2021 2020 ​ Cash paid for operating leases $ 6,058 ​ $ 5,934 ​ $ 18,037 ​ $ 17,336 ​ Right-of-use assets obtained in exchange for operating lease liabilities $ 7,169 ​ $ 9,586 ​ $ 14,402 ​ $ 34,064 ​

STOCK-BASED COMPENSATION (Table

STOCK-BASED COMPENSATION (Tables)	9 Months Ended
	Sep. 30, 2021
STOCK-BASED COMPENSATION
Schedule of stock-based compensation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Stock-based compensation expense ​ $ 3,674 ​ $ 3,781 ​ $ 12,819 ​ $ 9,666
Summary of changes in RSUs	​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2021 ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Grant Date ​ ​ RSUs ​ Fair Value RSUs outstanding at beginning of period 608 ​ $ 58.15 RSUs granted 388 ​ $ 95.96 RSUs vested (177) ​ $ 62.73 RSUs forfeited (182) ​ $ 68.49 RSUs outstanding at end of period 637 ​ $ 76.97
Summary of changes in stock options	​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, 2021 ​ ​ Weighted- ​ ​ ​ ​ Average ​ ​ Number of ​ Exercise Price ​ ​ Options ​ per Share Options outstanding at beginning of period 147 ​ $ 23.63 Options exercised (35) ​ $ 21.10 Options expired — ​ $ — Options outstanding at end of period 112 ​ $ 24.41

SIGNIFICANT CUSTOMER INFORMAT_2

SIGNIFICANT CUSTOMER INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2021
Sales Revenue, Net [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Schedules of significant customer information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ Applied Materials, Inc. ​ $ 77,136 22.3 % $ 65,740 16.9 % Lam Research ​ $ 39,149 11.3 % ​ ​ 40,798 10.5 % ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Nine Months Ended September 30, ​ ​ 2021 ​ ​ 2020 ​ Applied Materials, Inc. ​ $ 218,757 20.7 % $ 181,129 17.3 % Lam Research ​ $ 109,734 10.4 % ​ ​ * * %
Accounts Receivable [Member] | Credit Concentration Risk [Member]
Concentration Risk [Line Items]
Schedules of significant customer information	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ ​ ​ 2021 ​ ​ 2020 ​ Applied Materials, Inc. ​ $ 41,159 18.7 % $ 33,402 14.2 % Nidec Motor Corporation ​ ​ * ​ * % $ 24,344 ​ 10.4 % ​ * Customer’s balance was less than 10% of total.

CREDIT FACILITY (Tables)

CREDIT FACILITY (Tables)	9 Months Ended
	Sep. 30, 2021
CREDIT FACILITY
Schedule of borrowings under credit facility	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, 2021 ​ ​ Balance Interest Rate Unused Line Fee Term Loan Facility subject to a fixed interest rate ​ $ 260,094 ​ 1.271% ​ - Term Loan Facility subject to a variable interest rate ​ ​ 139,906 ​ 0.890% ​ - Revolving Facility subject to a variable interest rate ​ ​ — ​ 0.890% ​ 0.10% Total borrowings under the Credit Agreement ​ $ 400,000 ​ ​ ​ ​
Schedule of debt obligation	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ September 30, ​ December 31, ​ 2021 2020 Term Loan Facility ​ $ 400,000 ​ $ 323,750 Less: debt issuance costs ​ ​ (2,403) ​ ​ (1,704) Total debt ​ ​ 397,597 ​ ​ 322,046 Less current portion of long-term debt ​ ​ (20,000) ​ ​ (17,500) Total long-term debt ​ $ 377,597 ​ $ 304,546
Schedule of contractual maturities of debt obligations	​ ​ ​ ​ ​ Year Ending December 31, ​ 2021 (remaining) ​ $ 5,000 2022 ​ ​ 20,000 2023 ​ ​ 20,000 2024 ​ ​ 20,000 2025 ​ ​ 20,000 Thereafter ​ ​ 315,000 Total ​ $ 400,000
Schedule of interest expense and unused line of credit fees	​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Three Months Ended September 30, ​ Nine Months Ended September 30, ​ 2021 2020 2021 2020 Interest expense ​ $ 1,009 ​ $ 778 ​ $ 2,973 ​ $ 4,021 Amortization of debt issuance costs ​ ​ 420 ​ ​ 129 ​ ​ 669 ​ ​ 392 Unused line of credit fees and other ​ ​ 41 ​ ​ 38 ​ ​ 116 ​ ​ 114 Total interest expense ​ $ 1,470 ​ $ 945 ​ $ 3,758 ​ $ 4,527

ACQUISITIONS - Intangible Asset

ACQUISITIONS - Intangible Assets Acquired (Details) - Technology Equipment [Member] $ in Millions	1 Months Ended
	Jan. 31, 2021USD ($)
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets acquired	$ 3.6
Contingent consideration	$ 2.9
Useful Life	5 years

ACQUISITIONS - Consideration Tr

ACQUISITIONS - Consideration Transferred (Details) - USD ($) $ in Thousands	Jun. 01, 2021	Dec. 31, 2020
TEGAM, Inc. [Member]
Business Acquisition [Line Items]
Cash paid for acquisition	$ 15,552
Holdback	2,100
Total fair value of consideration transferred	17,652
Less cash acquired	(472)
Total purchase price	$ 17,180
Acquired percentage	100.00%
Versatile Power, Inc. [Member]
Business Acquisition [Line Items]
Cash paid for acquisition		$ 4,654
Holdback		950
Contingent consideration		1,500
Total fair value of consideration transferred		7,104
Less cash acquired		(245)
Total purchase price		$ 6,859
Acquired percentage		100.00%

ACQUISITIONS - Assets Acquired

ACQUISITIONS - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Jun. 01, 2021	Dec. 31, 2020
TEGAM, Inc. [Member]
Business Acquisition [Line Items]
Current assets and liabilities, net		$ 3,870
Property and equipment		734
Operating lease right-of-use assets		425
Intangible assets		6,900
Goodwill		5,670
Other non-current assets		31
Total assets acquired		17,630
Other non-current liabilities		25
Operating lease liability		425
Total liabilities assumed		450
Total fair value of net assets acquired		$ 17,180
Versatile Power, Inc. [Member]
Business Acquisition [Line Items]
Total fair value of net assets acquired			$ 6,859
Versatile Power, Inc. [Member] | Preliminary Fair Value [Member]
Business Acquisition [Line Items]
Current assets and liabilities, net	$ 1,013
Property and equipment	35
Operating lease right-of-use assets	463
Intangible assets	4,000
Goodwill	1,831
Total assets acquired	7,342
Other non-current liabilities	20
Operating lease liability	463
Total liabilities assumed	483
Total fair value of net assets acquired	$ 6,859

REVENUE - Nature of Goods and S

REVENUE - Nature of Goods and Services (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
REVENUE
Deferred revenue	$ 7,908	$ 8,671

REVENUE - Revenue by Product Li

REVENUE - Revenue by Product Line (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 346,093	$ 389,521	$ 1,059,024	$ 1,044,857
United States [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	139,089	152,503	410,212	389,007
North America (excluding U.S.) [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	24,708	38,126	77,067	115,712
Asia [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	135,838	180,660	434,232	462,388
Europe [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	44,838	17,886	129,751	76,070
Other countries [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,620	346	7,762	1,680
Semiconductor Equipment [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	173,441	167,058	530,828	446,107
Industrial and Medical [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	80,800	87,013	242,412	219,877
Data Center Computing [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	62,231	87,741	190,843	257,240
Telecom and Networking [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	29,621	47,709	94,941	121,633
Product [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	312,389	358,257	956,790	959,388
Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 33,704	$ 31,264	$ 102,234	$ 85,469

REVENUE - Extended Warranty Rev

REVENUE - Extended Warranty Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 346,093	$ 389,521	$ 1,059,024	$ 1,044,857
Recognized at Point in Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	345,548	389,306	1,058,012	1,044,255
Recognized over Time [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 545	$ 215	$ 1,012	$ 602

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
INCOME TAXES
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%

INCOME TAXES - Schedule of tax

INCOME TAXES - Schedule of tax expense and effective tax rate for income from continuing operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
INCOME TAXES
Income from continuing operations, before income taxes	$ 24,704	$ 52,396	$ 105,797	$ 108,583
Provision for income taxes	$ 3,657	$ 6,783	$ 10,817	$ 15,293
Effective tax rate	14.80%	12.90%	10.20%	14.10%

EARNINGS PER SHARE - Reconcilia

EARNINGS PER SHARE - Reconciliation of weighted-average shares outstanding used in calculation of basic and diluted EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
EARNINGS PER SHARE
Income from continuing operations	$ 21,047	$ 45,613	$ 94,980	$ 93,290
Income from continuing operations attributable to noncontrolling interest	6	36	70	35
Income from continuing operations attributable to Advanced Energy Industries, Inc.	$ 21,041	$ 45,577	$ 94,910	$ 93,255
Basic weighted-average common shares outstanding	38,183	38,325	38,296	38,322
Assumed exercise of dilutive stock options and restricted stock units	180	203	221	209
Diluted weighted-average common shares outstanding	38,363	38,528	38,517	38,531
Continuing Operations:
Basic earnings per share	$ 0.55	$ 1.19	$ 2.48	$ 2.43
Diluted earnings per share	$ 0.55	$ 1.18	$ 2.46	$ 2.42

EARNINGS PER SHARE - Schedule o

EARNINGS PER SHARE - Schedule of stock options and restricted units excluded in the computation of diluted earnings per share (Details) - shares shares in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021
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	82	2

EARNINGS PER SHARE - Share Repu

EARNINGS PER SHARE - Share Repurchase (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	3 Months Ended				9 Months Ended
	Nov. 08, 2021	Sep. 30, 2021	Jun. 30, 2021	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2021	Sep. 30, 2020	Jul. 29, 2021
Equity, Class of Treasury Stock [Line Items]
Amount paid and accrued to repurchase shares		$ 52,555	$ 6,503	$ 4,331	$ 7,248	$ 59,058	$ 11,579
Number of shares repurchased		605,000		73,000		677,000	243,000
Average repurchase price per share		$ 86.93		$ 59.70		$ 87.30	$ 47.70
Remaining authorized by Board of Directors for future repurchases as of period end		$ 147,444		$ 38,420		$ 147,444	$ 38,420
Shares repurchased from related parties						0
Stock repurchase plan authorized amount								$ 200,000
Subsequent Event [Member]
Equity, Class of Treasury Stock [Line Items]
Amount paid and accrued to repurchase shares	$ 10,400
Number of shares repurchased	121,000

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 2,923	$ 2,654
Total liabilities	5,221	7,760
Contingent Consideration [Member] | Other Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	2,169	2,009
Contingent Consideration [Member] | Other Long-Term Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	3,052	2,940
Interest Rate Swaps [Member] | Other Long-Term Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities		2,811
Certificates of Deposit [Member] | Marketable Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	2,833	2,654
Foreign Exchange Forward [Member] | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	38
Interest Rate Swaps [Member] | Deposits and Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	52
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	2,923	2,654
Total liabilities		2,811
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swaps [Member] | Other Long-Term Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities		2,811
Fair Value, Inputs, Level 2 [Member] | Certificates of Deposit [Member] | Marketable Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	2,833	2,654
Fair Value, Inputs, Level 2 [Member] | Foreign Exchange Forward [Member] | Other Current Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	38
Fair Value, Inputs, Level 2 [Member] | Interest Rate Swaps [Member] | Deposits and Other Assets [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	52
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	5,221	4,949
Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member] | Other Current Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	2,169	2,009
Fair Value, Inputs, Level 3 [Member] | Contingent Consideration [Member] | Other Long-Term Liabilities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total liabilities	$ 3,052	$ 2,940

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
FAIR VALUE MEASUREMENTS
Transfer into Level 3, Liabilities	$ 0	$ 0
Transfer from Level 3, Liabilities	0	0
Transfer into Level 3, Assets	0	0
Transfer from Level 3, Assets	$ 0	$ 0

DERIVATIVE FINANCIAL INSTRUME_3

DERIVATIVE FINANCIAL INSTRUMENTS (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Derivative Instruments, Gain (Loss) [Line Items]
Annual interest (as a percent)	1.271%
Average fixed rate	0.521%
Cash Flow Hedge [Member] | Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Basis points at current leverage ratios	75
Foreign Exchange Forward [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, notional amount	$ 45,550

DERIVATIVE FINANCIAL INSTRUME_4

DERIVATIVE FINANCIAL INSTRUMENTS - Qualified Hedging Instruments (Details) - Interest Rate Swaps [Member] - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2021	Dec. 31, 2020
Derivative [Line Items]
Derivative, notional amount	$ 260,094	$ 273,219
Balances recorded in Accumulated other comprehensive loss	$ (40)	$ 2,139

ACCOUNTS AND OTHER RECEIVABLE_3

ACCOUNTS AND OTHER RECEIVABLE, NET (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total receivables, net	$ 220,112	$ 235,178
Amounts billed, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total receivables, net	192,147	213,560
Unbilled receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total receivables, net	$ 27,965	$ 21,618

ACCOUNTS AND OTHER RECEIVABLE_4

ACCOUNTS AND OTHER RECEIVABLE, NET - Expected Credit losses - (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
ACCOUNTS AND OTHER RECEIVABLE, NET
Balance as of beginning of period	$ 7,602
Deductions - write-offs, net of recoveries	(677)
Foreign currency translation	(22)
Other	(1,248)
Balance as of end of period	$ 5,655

INVENTORIES (Details)

INVENTORIES (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
INVENTORIES
Parts and raw materials	$ 258,281	$ 141,337
Work in process	21,569	13,702
Finished goods	61,650	66,307
Total	$ 341,500	$ 221,346

PROPERTY AND EQUIPMENT, NET - D

PROPERTY AND EQUIPMENT, NET - Details of property and equipment (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 212,794	$ 195,094
Less: Accumulated depreciation	(97,993)	(80,363)
Property and equipment, net	114,801	114,731
Buildings and Land [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	1,631	1,776
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	126,896	115,404
Computer and Communication Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	27,589	26,623
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	5,055	4,352
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	261	262
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	46,345	42,984
Construction in Process [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, gross	$ 5,017	$ 3,693

PROPERTY AND EQUIPMENT, NET -_2

PROPERTY AND EQUIPMENT, NET - Depreciation expense recorded in continuing operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
PROPERTY AND EQUIPMENT, NET
Depreciation expense	$ 7,874	$ 7,188	$ 22,721	$ 20,369

GOODWILL - Schedule of the chan

GOODWILL - Schedule of the changes in goodwill (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
GOODWILL AND INTANGIBLE ASSETS
Balance at beginning of period	$ 209,983
Measurement period adjustments to preliminary purchase price allocation	(82)
Additions from acquisition	5,670
Foreign currency translation	(2,110)
Balance at end of period	$ 213,625

INTANGIBLE ASSETS - Schedule of

INTANGIBLE ASSETS - Schedule of intangible assets (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	$ 237,587	$ 226,267
Finite-Lived Intangible Assets, Accumulated Amortization	(72,555)	(57,328)
Finite-lived intangible assets, net	165,032	168,939
Technology Equipment [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	91,605	85,075
Finite-Lived Intangible Assets, Accumulated Amortization	(33,055)	(24,999)
Finite-lived intangible assets, net	58,550	60,076
Customer Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	118,733	114,171
Finite-Lived Intangible Assets, Accumulated Amortization	(32,182)	(26,880)
Finite-lived intangible assets, net	86,551	87,291
Trademarks and other [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Gross	27,249	27,021
Finite-Lived Intangible Assets, Accumulated Amortization	(7,318)	(5,449)
Finite-lived intangible assets, net	$ 19,931	$ 21,572

INTANGIBLE ASSETS - Schedule _2

INTANGIBLE ASSETS - Schedule of amortization expense relating to intangible assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
GOODWILL AND INTANGIBLE ASSETS
Amortization expense	$ 5,607	$ 5,049	$ 16,504	$ 15,064

INTANGIBLE ASSETS - Schedule _3

INTANGIBLE ASSETS - Schedule of Finite-Lived Intangible Assets, Future Amortization Expense (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
GOODWILL AND INTANGIBLE ASSETS
2021 (remaining)	$ 5,541
2022	22,043
2023	22,024
2024	19,153
2025	14,665
Thereafter	81,606
Finite-lived intangible assets, net	$ 165,032	$ 168,939

RESTRUCTURING COSTS (Details)

RESTRUCTURING COSTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		45 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 1,272	$ 1,494	$ 2,521	$ 7,940	$ 24,964
Severance and related charges
Restructuring Cost and Reserve [Line Items]
Restructuring expense	676	202	1,270	5,207	18,183
Facility relocation and closure charges
Restructuring Cost and Reserve [Line Items]
Restructuring expense	$ 596	$ 1,292	$ 1,251	$ 2,733	$ 6,781

RESTRUCTURING COSTS - Schedule

RESTRUCTURING COSTS - Schedule of Restructuring liabilities (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		45 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021
Restructuring Reserve [Roll Forward]
Beginning balance			$ 10,641
Cost incurred and charged to expense	$ 1,272	$ 1,494	2,521	$ 7,940	$ 24,964
Cost paid or otherwise settled			(3,463)
Ending balance	$ 9,699		$ 9,699		$ 9,699

WARRANTIES - Narrative (Details

WARRANTIES - Narrative (Details)	9 Months Ended
	Sep. 30, 2021
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 Product

WARRANTIES - Changes in Product Warranty Obligation (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2021USD ($)
Movement in Standard Product Warranty Accrual [Roll Forward]
Balance at beginning of period	$ 4,780
Increases to accruals	2,290
Warranty expenditures	(3,404)
Effect of changes in exchange rates	(4)
Balance at end of period	$ 3,662

LEASES - Components of operatin

LEASES - Components of operating lease cost (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
LEASES
Operating lease cost	$ 5,735	$ 4,806	$ 17,708	$ 14,500
Short-term and variable lease cost	578	1,504	1,704	4,151
Total operating lease cost	$ 6,313	$ 6,310	$ 19,412	$ 18,651

LEASES - Operating lease maturi

LEASES - Operating lease maturity schedule (Details) $ in Thousands	Sep. 30, 2021USD ($)
LEASES
2021 (remaining)	$ 5,507
2022	20,004
2023	16,685
2024	14,295
2025	12,027
Thereafter	75,473
Total lease payments	143,991
Less: Interest	(31,517)
Present value of lease liabilities	112,474
Payments for lease agreements that commence in the future	$ 3,900

LEASES - Other lease cost infor

LEASES - Other lease cost information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
LEASES
Weighted average remaining lease term (in years)	9 years 10 months 28 days		9 years 10 months 28 days		10 years 7 months 24 days
Weighted average discount rate	4.51%		4.51%		4.63%
Cash paid for operating leases	$ 6,058	$ 5,934	$ 18,037	$ 17,336
Right-of-use assets obtained in exchange for operating lease liabilities	$ 7,169	$ 9,586	$ 14,402	$ 34,064

STOCK-BASED COMPENSATION - Narr

STOCK-BASED COMPENSATION - Narrative (Details) shares in Millions	9 Months Ended
	Sep. 30, 2021shares
2017 OMNIBUS Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1.9
Restricted Stock Units (RSUs) [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock Units (RSUs) [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Stock Option Awards [Member]
Awards term	10 years
Stock Option Awards [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Stock Option Awards [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years

STOCK-BASED COMPENSATION - Sche

STOCK-BASED COMPENSATION - Schedule of stock-based compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
STOCK-BASED COMPENSATION
Stock-based compensation expense	$ 3,674	$ 3,781	$ 12,819	$ 9,666

STOCK-BASED COMPENSATION - Summ

STOCK-BASED COMPENSATION - Summary of Restricted Stock Units activity (Details) - Restricted Stock Units (RSUs) [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at the beginning of period | shares	608
Granted | shares	388
Vested | shares	(177)
Forfeited | shares	(182)
Outstanding at the end of period | shares	637
Weighted Average Grant Date Fair Value, Beginning Balance | $ / shares	$ 58.15
Weighted Average Grant Date Fair Value, Granted | $ / shares	95.96
Weighted Average Grant Date Fair Value, Vested | $ / shares	62.73
Weighted Average Grant Date Fair Value, Forfeited | $ / shares	68.49
Weighted Average Grant Date Fair Value, Ending Balance | $ / shares	$ 76.97

STOCK-BASED COMPENSATION - Su_2

STOCK-BASED COMPENSATION - Summary of stock option activity (Details) - Time Based [Member] shares in Thousands	9 Months Ended
	Sep. 30, 2021$ / sharesshares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding at beginning of period | shares	147
Exercised | shares	(35)
Outstanding at ending of period | shares	112
Weighted-Average Exercise Price Per Share, Beginning Balance | $ / shares	$ 23.63
Weighted-Average Exercise Price Per Share, Exercised | $ / shares	21.10
Weighted-Average Exercise Price Per Share, End Balance | $ / shares	$ 24.41

SIGNIFICANT CUSTOMER INFORMAT_3

SIGNIFICANT CUSTOMER INFORMATION (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Revenue, Major Customer [Line Items]
Sales, net	$ 346,093	$ 389,521	$ 1,059,024	$ 1,044,857
Product [Member]
Revenue, Major Customer [Line Items]
Sales, net	312,389	358,257	956,790	959,388
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Applied Materials, Inc. [Member]
Revenue, Major Customer [Line Items]
Sales, net	$ 77,136	$ 65,740	$ 218,757	$ 181,129
Significant concentration risk, 10% or more of total balance	22.30%	16.90%	20.70%	17.30%
Sales Revenue, Net [Member] | Customer Concentration Risk [Member] | Lam Research [Member]
Revenue, Major Customer [Line Items]
Sales, net	$ 39,149	$ 40,798	$ 109,734
Significant concentration risk, 10% or more of total balance	11.30%	10.50%	10.40%
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Applied Materials, Inc. [Member]
Revenue, Major Customer [Line Items]
Significant concentration risk, 10% or more of total balance			18.70%		14.20%
Accounts receivable	$ 41,159		$ 41,159		$ 33,402
Accounts Receivable [Member] | Credit Concentration Risk [Member] | Nidec Motor Corporation [Member]
Revenue, Major Customer [Line Items]
Significant concentration risk, 10% or more of total balance					10.40%
Accounts receivable					$ 24,344

CREDIT FACILITY (Details)

CREDIT FACILITY (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2019
Line of Credit Facility [Line Items]
Additional borrowings	$ 85,000	$ 85,000
Balance	400,000	400,000	$ 323,750
Fair value of long-term debt	$ 400,000	$ 400,000
Average fixed rate	0.521%	0.521%
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity				$ 500,000
Credit availability under the Loan Agreement	$ 200,000	$ 200,000	150,000
Term Loan Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity				350,000
Unsecured Revolving Facility [Member]
Line of Credit Facility [Line Items]
Line of credit facility, borrowing capacity	200,000	200,000		$ 150,000
Increase in borrowing capacity	50,000	50,000
Term Loan, Fixed Interest Rate [Member]
Line of Credit Facility [Line Items]
Balance	$ 260,094	$ 260,094
Interest Rate	1.271%	1.271%
Term Loan, Variable Interest Rate [Member]
Line of Credit Facility [Line Items]
Balance	$ 139,906	$ 139,906
Interest Rate	0.89%	0.89%
Revolving Facility, Variable Interest Rate [Member]
Line of Credit Facility [Line Items]
Interest Rate	0.89%	0.89%
Unused Line Fee		0.10%
Foreign Exchange Forward [Member]
Line of Credit Facility [Line Items]
Derivative, notional amount	$ 45,550	$ 45,550
Interest Rate Swaps [Member]
Line of Credit Facility [Line Items]
Derivative, notional amount	$ 260,094	$ 260,094	$ 273,219

CREDIT FACILITY - Debt obligati

CREDIT FACILITY - Debt obligation (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt:
Term Loan Facility	$ 400,000	$ 323,750
Less: debt issuance costs	(2,403)	(1,704)
Total debt	397,597	322,046
Less current portion of long-term debt	(20,000)	(17,500)
Total long-term debt	$ 377,597	$ 304,546

CREDIT FACILITY - Contractual m

CREDIT FACILITY - Contractual maturities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
CREDIT FACILITY
2021 (remaining)	$ 5,000
2022	20,000
2023	20,000
2024	20,000
2025	20,000
Thereafter	315,000
Total	$ 400,000	$ 323,750

CREDIT FACILITY - Interest expe

CREDIT FACILITY - Interest expense and unused line of credit fees (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
CREDIT FACILITY
Interest expense	$ 1,009	$ 778	$ 2,973	$ 4,021
Amortization of debt issuance costs	420	129	669	392
Unused line of credit fees and other	41	38	116	114
Total interest expense	$ 1,470	$ 945	$ 3,758	$ 4,527