Ultra Clean (UCTT) 10-K 23 Feb 21 2020 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Feb. 19, 2021	Jun. 26, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 25, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Trading Symbol	UCTT
Entity Registrant Name	Ultra Clean Holdings, Inc.
Entity Central Index Key	0001275014
Current Fiscal Year End Date	--12-25
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Filer Category	Large Accelerated Filer
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		40,612,933
Entity Public Float			$ 865.9
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock, $0.001 par value
Security Exchange Name	NASDAQ
Entity File Number	000-50646
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	61-1430858
Entity Address, Address Line One	26462 Corporate Avenue
Entity Address, City or Town	Hayward
Entity Address, State or Province	CA
Entity Address, Postal Zip Code	94545
City Area Code	510
Local Phone Number	576-4400
Document Annual Report	true
Document Transition Report	false
Documents Incorporated by Reference	Portions of the registrant’s definitive proxy statement to be delivered to stockholders in connection with the 2020 annual meeting of stockholders are incorporated by reference in Part III of this Form 10-K where indicated. Such proxy statement will be filed with the Securities and Exchange Commission within 120 days of the registrant’s fiscal year ended December 25, 2020.

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 25, 2020	Dec. 27, 2019
Current assets:
Cash and cash equivalents	$ 200.3	$ 162.5
Accounts receivable, net of allowance for doubtful accounts of $0.3 at December 25, 2020 and December 27, 2019	145.5	112.7
Inventories	180.4	172.4
Prepaid expenses and other current assets	18.9	19.4
Total current assets	545.1	467
Property, plant and equipment, net	159.2	145.3
Goodwill	171.1	171.1
Intangibles assets, net	160.5	180.3
Deferred tax assets, net	23.5	15.5
Operating lease right-of-use assets	37.8	34.9
Other non-current assets	5.3	5.2
Total assets	1,102.5	1,019.3
Current liabilities:
Bank borrowings	7.4	8.8
Accounts payable	121.3	133.1
Accrued compensation and related benefits	34.5	24.8
Operating lease liabilities	11.7	13.2
Other current liabilities	26.3	30.7
Total current liabilities	201.2	210.6
Bank borrowings, net of current portion	261.6	283.4
Deferred tax liabilities	33.6	25.2
Operating lease liabilities	31.1	28.8
Other liabilities	23.8	18.8
Total liabilities	551.3	566.8
Commitments and contingencies (See Note 9)
UCT stockholders’ equity:
Preferred stock — $0.001 par value, 10.0 authorized; none outstanding
Common stock — $0.001 par value, 90.0 authorized; 40.6 and 39.9 shares issued and outstanding at December 25, 2020 and December 27, 2019, respectively	0.1	0.1
Additional paid-in capital	312.8	300.9
Common shares held in treasury, at cost, 0.6 shares at December 25, 2020 and December 27, 2019	(3.3)	(3.3)
Retained earnings	217.9	140.3
Accumulated other comprehensive income (loss)	5.1	(1.3)
Total UCT stockholders' equity	532.6	436.7
Noncontrolling interests	18.6	15.8
Total equity	551.2	452.5
Total liabilities and equity	$ 1,102.5	$ 1,019.3

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - USD ($) shares in Millions, $ in Millions	Dec. 25, 2020	Dec. 27, 2019
Statement Of Financial Position [Abstract]
Account receivable, allowance for doubtful accounts	$ 0.3	$ 0.3
Preferred stock, par value	$ 0.001	$ 0.001
Preferred stock, shares authorized	10	10
Preferred stock, shares outstanding	0	0
Common stock, par value	$ 0.001	$ 0.001
Common stock, shares authorized	90	90
Common stock, shares issued	40.6	39.9
Common stock, shares outstanding	40.6	39.9
Treasury stock, shares	0.6	0.6

Consolidated Statements of Oper

Consolidated Statements of Operations - USD ($) $ in Thousands	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Revenues:
Total revenues	$ 1,398,600	$ 1,066,200	$ 1,096,500
Cost of revenues:
Total cost revenues	1,106,800	869,400	920,700
Gross margin	291,800	196,800	175,800
Operating expenses:
Research and development	14,800	14,600	13,300
Sales and marketing	25,100	22,400	16,300
General and administrative	130,500	129,900	85,500
Total operating expenses	170,400	166,900	115,100
Income from operations	121,400	29,900	60,700
Interest income	900	400	300
Interest expense	16,900	25,600	10,000
Other income (expense), net	(5,700)	(2,400)	1,300
Income before provision for income taxes	99,700	2,300	52,300
Provision for income taxes	19,300	10,000	15,300
Net income (loss)	80,400	(7,700)	37,000
Less: Net income attributable to noncontrolling interests	2,800	1,700	400
Net income (loss) attributable to UCT	$ 77,600	$ (9,400)	$ 36,600
Net income (loss) per share attributable to UCT common stockholders:
Basic	$ 1.93	$ (0.24)	$ 0.95
Diluted	$ 1.89	$ (0.24)	$ 0.94
Shares used in computing net income (loss) per share:
Basic	40.2	39.5	38.4
Diluted	41.1	39.5	38.9
Product [Member]
Revenues:
Product	$ 1,131,200	$ 840,800	$ 1,015,500
Cost of revenues:
Product	934,700	719,000	865,200
Services [Member]
Revenues:
Product	267,400	225,400	81,000
Cost of revenues:
Product	$ 172,100	$ 150,400	$ 55,500

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ 80.4	$ (7.7)	$ 37
Other comprehensive income (loss):
Change in cumulative translation adjustment	6.5	(0.4)	(1.3)
Change in pension net actuarial loss	(0.1)	(0.3)
Cash flow hedges:
Change in fair value of derivatives			(0.1)
Adjustment for net loss realized and included in net income			(1)
Total change in unrealized gain (loss) on derivative instruments			(1.1)
Total other comprehensive income (loss), net of tax	6.4	(0.7)	(2.4)
Other comprehensive income, net of tax, attributable to noncontrolling interests	2.8	1.7	0.4
Comprehensive income (loss) attributable to UCT	$ 84	$ (10.1)	$ 34.2

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Cash flows from operating activities:
Net income (loss)	$ 80.4	$ (7.7)	$ 37
Adjustments to reconcile net income (loss) to net cash provided by operating activities (excluding assets acquired, liabilities assumed and noncontrolling interests at acquisition):
Depreciation and amortization	25	21.5	11.5
Amortization of intangible assets	19.8	20.1	9.6
Stock-based compensation	12.7	12.1	10.3
Amortization of debt issuance costs	1.9	1.8	0.8
Loss (gain) on the disposal of assets and business	1.4	(2)	(1)
Gain from insurance proceeds	(1)
Deferred income taxes	0.4	(3.6)	(0.1)
Change in the fair value of financial instruments	7.7	2.8	(0.3)
Changes in assets and liabilities, net of effects of acquisitions:
Accounts receivable	(32.7)	(4.5)	7.2
Inventories	(8)	22.3	50.2
Prepaid expenses and other current assets	1.2	3.7	2.6
Other non-current assets	(0.1)		(0.4)
Accounts payable	(12.6)	31	(83.2)
Accrued compensation and related benefits	9.7	9	(2.8)
Income taxes payable	2.8	(2.9)	0.8
Operating lease assets and liabilities	(1.1)	7.1
Other liabilities	(7.4)	6.3	(2.5)
Net cash provided by operating activities	97.3	121	41.7
Cash flows from investing activities:
Purchases of property, plant and equipment	(36.4)	(26.3)	(26.1)
Proceeds from sale of equipment, including insurance proceeds	6.6	7
Acquisition of businesses, net of cash acquired		(29.9)	(319.8)
Net cash used in investing activities	(29.8)	(49.2)	(345.9)
Cash flows from financing activities:
Proceeds from bank borrowings	76.7	41.8	387.1
Proceeds from issuance of common stock	0.6	0.3	94.6
Principal payments on bank borrowings and finance leases	(105.5)	(93)	(86.4)
Payment of contingent earn-out	(1.4)
Payments of debt issuance costs			(12.1)
Payments of dividends to a joint venture shareholder		(0.6)
Employees’ taxes paid upon vesting of restricted stock units	(1.5)	(1.9)	(3.1)
Net cash used in financing activities	(31.1)	(53.4)	380.1
Effect of exchange rate changes on cash and cash equivalents	1.4		(0.1)
Net increase in cash and cash equivalents	37.8	18.4	75.8
Cash and cash equivalents at beginning of period	162.5	144.1	68.3
Cash and cash equivalents at end of period	200.3	162.5	144.1
Supplemental cash flow information:
Income taxes paid, net of income tax refunds	16.4	14.5	14.5
Interest paid	15.6	23.6	7.1
Non-cash investing and financing activities:
Property, plant and equipment purchased included in accounts payable and other liabilities	$ 3.2	5	5.6
Impairment loss due to a facility fire covered by insurance			6
Note receivable received in exchange for sale of UAMC			0.3
Fair value of earn-out payment related to business acquisitions		$ 1.4	$ 4.2

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - USD ($) $ in Millions	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Treasury Shares [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total stock holder's Equity of UCT [Member]	Noncontrolling Interests [Member]
Beginning balance at Dec. 29, 2017	$ 300.3	$ 0.1	$ 188.6	$ (3.3)	$ 113.1	$ 1.8	$ 300.3
Beginning balance, Shares at Dec. 29, 2017		33,700,000		600,000
Issuance under employee stock plans	0.3		0.3				0.3
Issuance under employee stock plans, Shares		800,000
Stock-based compensation expense	10.3		10.3				10.3
Employees’ taxes paid upon vesting of restricted stock units	(3.1)		(3.1)				(3.1)
Employees' taxes paid upon vesting of restricted stock units, Shares		(200,000)
Issuance of common stock in public offering	94.3		94.3				94.3
Issuance of common stock in public offering, Shares		4,800,000
Noncontrolling interests from acquisition of QGT	14.3							$ 14.3
Net income (loss)	37				36.6		36.6	0.4
Other comprehensive income (loss)	(2.4)					(2.4)	(2.4)
Ending balance at Dec. 28, 2018	451	$ 0.1	290.4	$ (3.3)	149.7	(0.6)	436.3	14.7
Ending balance, Shares at Dec. 28, 2018		39,100,000		600,000
Issuance under employee stock plans	0.3		0.3				0.3
Issuance under employee stock plans, Shares		900,000
Stock-based compensation expense	12.1		12.1				12.1
Employees’ taxes paid upon vesting of restricted stock units	(1.9)		(1.9)				(1.9)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Net income (loss)	(7.7)				(9.4)		(9.4)	1.7
Dividend payments to a joint venture shareholder	(0.6)							(0.6)
Other comprehensive income (loss)	(0.7)					(0.7)	(0.7)
Ending balance at Dec. 27, 2019	452.5	$ 0.1	300.9	$ (3.3)	140.3	(1.3)	436.7	15.8
Ending balance, Shares at Dec. 27, 2019		39,900,000		600,000
Issuance under employee stock plans	0.6		0.6				0.6
Issuance under employee stock plans, Shares		800,000
Stock-based compensation expense	12.8		12.8				12.8
Employees’ taxes paid upon vesting of restricted stock units	(1.5)		(1.5)				(1.5)
Employees' taxes paid upon vesting of restricted stock units, Shares		(100,000)
Net income (loss)	80.4				77.6		77.6	2.8
Other comprehensive income (loss)	6.4					6.4	6.4
Ending balance at Dec. 25, 2020	$ 551.2	$ 0.1	$ 312.8	$ (3.3)	$ 217.9	$ 5.1	$ 532.6	$ 18.6
Ending balance, Shares at Dec. 25, 2020		40,600,000		600,000

Organization and Significant Ac

Organization and Significant Accounting Policies	12 Months Ended
	Dec. 25, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Organization and Significant Accounting Policies	1. ORGANIZATION AND SIGNIFICANT ACCOUNTING POLICIES Organization Ultra Clean Holdings, Inc., (the “Company” or “UCT”) a Delaware corporation, was founded in November 2002 and became a publicly traded company on the NASDAQ Global Market in March 2004. The Company is a global leader in Fiscal Year The Company uses a 52-53-week fiscal year ending on the Friday nearest December 31. All references to quarters refer to fiscal quarters and all references to years refer to fiscal years. Principles of Consolidation The Company’s Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and all intercompany accounts and transactions have been eliminated in consolidation. Noncontrolling interests Noncontrolling interests are recognized to reflect Segments The Financial Accounting Foreign Currency Translation and Remeasurement As of December 25, 2020, the functional currency of the Products business unit’s foreign subsidiaries is the U.S. dollar. The functional currency of the Service business unit’s foreign subsidiaries is the local currency except for that of its Singapore and Scotland entities, which is the U.S. dollar. Due to the changes in economic factors in FDS and in S ervices’ entity in Scotland in fiscal 2020 , the Company determined that the functional currency designation of FDS and Services’ entity in Scotland is the U.S. dollar , a change from the functional foreign currency utilized in the prior year. The impact of these changes was not significant. For the Company’s foreign subsidiaries where the local currency is the functional currency, the Company translates the financial statements of these subsidiaries to U.S. dollars using month-end exchange rates for assets and liabilities, and average exchange rates for revenue, costs and expenses. Translation gains and losses are recorded in accumulated other comprehensive income (AOCI) within UCT stockholders’ equity. For the Company’s foreign subsidiaries where the U.S. dollar is the functional currency, any gains and losses resulting from the translation of the assets and liabilities of these subsidiaries are recorded in other income (expense), net. Use of Estimates The presentation U.S. generally accepted accounting principles (“GAAP”) Cash and Cash Equivalents The Company considers currency on hand, demand deposits, time deposits, and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash and cash equivalents. Cash and cash equivalents are held in various financial institutions in the United States and internationally. Concentration of Credit Risk Financial instruments which subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. The Company sells its products and provides services primarily to semiconductor capital equipment manufacturers in the United States. The Company performs credit evaluations of its customers’ financial condition and generally requires no collateral. The Company’s most significant customers (having accounted for 10% or more of related) and their related revenues as a percentage of total revenues were as follows: Fiscal Year Ended 2020 2019 2018 Lam Research Corporation 42.9 % 41.7 % 55.1 % Applied Materials, Inc. 24.2 25.2 21.5 Total 67.1 % 66.9 % 76.6 % Three customers’ accounts receivable balances, Lam Research Corporation, Applied Materials, Inc. and ASM International, Inc., were individually greater than 10.0% of accounts receivable as of December 25, 2020 and December 27, 2019, in the aggregate approximately 62.9% and 66.7% of accounts receivable, respectively. Fair Value of Measurements The Company measures its cash equivalents, derivative contracts, contingent earn-out liabilities, pension obligation and common stock purchase obligation at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that is determined based on assumptions that market participants would use in pricing an asset or a liability. Assets and liabilities recorded at fair value are measured and classified in accordance with a three-tier fair value hierarchy based on the observability of the inputs available in the market used to measure fair value: Level 1 — Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2 — Inputs that are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant inputs are observable in the market or can be derived from observable market data. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs including interest rate curves, foreign exchange rates, and credit ratings. Level 3 — Unobservable inputs that are supported by little or no market activities. Derivative Financial Instruments The Company uses forward contracts to hedge a portion of, but not all, existing and anticipated foreign currency denominated transactions typically expected to occur within 24 months. The purpose of the hedge is to mitigate the effect of exchange rate fluctuations on certain foreign currency denominated costs and eventual cash flows. The Company recognizes derivative instruments as either assets or liabilities in the accompanying Consolidated Balance Sheets at fair value. The Company records changes in the fair value of the derivatives in the accompanying Consolidated Statements of Operations as other income (expense), net, or as a component of AOCI in the accompanying Consolidated Balance Sheets. Inventories Inventories are stated at the lower of cost (which approximates actual cost on a first-in, first-out basis) or net realizable value. The Company evaluates the valuation of all inventories, including raw materials, work-in-process, finished goods and spare parts on a periodic basis. Obsolete inventory or inventory in excess of management’s estimated usage is written down to its estimated market value less costs to sell, if less than its cost. Inherent in the estimates of market value are management’s estimates related to economic trends, future demand for products, and technological obsolescence of the Company’s products. Inventory write downs inherently involve judgments as to assumptions about expected future demand and the impact of market conditions on those assumptions. Although the Company believes that the assumptions it used in estimating inventory write downs are reasonable, significant changes in any one of the assumptions in the future could produce a significantly different result. There can be no assurances that future events and changing market conditions will not result in significant increases in inventory write downs. Property, Plant and Property, plant and equipment are stated at cost, or, in the case of equipment under finance leases, the present value of future minimum lease payments at inception of the related lease. The Company also capitalizes interest on borrowings related to eligible capital expenditures. Capitalized interest is added to the cost of the qualified assets and is subject to depreciation. Depreciation and amortization are computed using the straight-line method over the lesser of the estimated useful lives of the assets or the terms of the leases. Useful lives range from three to fifty years ten years Long-lived Assets The Company evaluates long-lived assets At the end of fiscal years 2020, 2019 and 2018, the Company assessed the useful lives of its long-lived assets, including property, plant and equipment as well as its intangible assets and concluded that no impairment was required. Leases The Company determines if an arrangement is a lease, or contains a lease, at the inception of the arrangement. When the Company determines the arrangement is a lease, or contains a lease, at lease inception, it then determines whether the lease is an operating lease or a finance lease. Operating and finance leases with lease terms of one year or greater result in the Company recording a right-of-use (ROU) asset and lease liability on its balance sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating and finance lease ROU assets and liabilities are initially recognized based on the present value of lease payments over the lease term. In determining the present value of lease payments, the Company uses the implicit interest rate if readily determinable or when the implicit interest rate is not readily determinable, the Company uses its incremental borrowing rate. The incremental borrowing rate is not a commonly quoted rate and is derived through a combination of inputs including the Company’s credit rating and the impact of full collateralization. The incremental borrowing rate is based on the Company’s collateralized borrowing capabilities over a similar term of the lease payments. The Company utilizes the consolidated group incremental borrowing rate for all leases. The operating lease ROU asset also includes any lease payments made and excludes any lease incentives. Specific lease terms used in computing the ROU assets and lease liabilities may include options to extend or terminate the lease when the Company believes it is reasonably certain that it will exercise that option. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. As allowed by the guidance, the Company has elected not to recognize ROU assets and lease liabilities that arise from short-term (12 months or less) leases for any class of underlying asset. Operating leases are included in operating lease ROU assets, other current liabilities, and long-term operating lease liabilities on the Company’s consolidated balance sheet. The Company’s finance leases at December 25, 2020 and December 27, 2019 were not significant. Goodwill and Indefinite Lived Intangible Assets Goodwill and indefinite-lived intangible assets are not amortized but are reviewed for impairment annually. Intangible assets are presented at cost, net of accumulated amortization, and are amortized on either a straight-line method or on an accelerated method over their estimated future discounted cash flows. The Company reviews goodwill and purchased intangible assets with indefinite lives for impairment annually and whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable, such as when reductions in demand or significant economic slowdowns in the semiconductor industry are present. There were no impairments of the Company’s goodwill and purchased intangible assets in fiscal year 2020. Deferred Debt Issuance Costs Debt issuance costs incurred in connection with Defined Benefit Pension Plan The Company has a noncontributory defined benefit pension plan covering substantially all of the employees of one of its foreign entities upon termination of their employee services. For further discussion of the Company’s defined benefit pension plan see Note 8 of Notes to the Consolidated Financial Statements. Revenue Recognition Revenue is recognized when control of the promised goods or services is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company performs the following five steps to determine when to recognize revenue: (1) identification of the contract(s) with customers, (2) identification of the performance obligations in the contract, (3) determination of the transaction price, (4) allocation of the transaction price to the performance obligations in the contract, and (5) recognition of revenue when, or as, a performance obligation is satisfied. Shipping and Handling Costs Shipping and handling costs are included as a component of cost of revenues. Research and Development Costs Research and development costs are expensed as incurred. Stock-Based Compensation Expense The Company maintains stock-based compensation plans which allow for the issuance of equity-based awards to executives and certain employees. These equity-based awards include stock options, restricted stock awards and restricted stock units. The Company also maintains an employee stock purchase plan (“ESPP”) that provides for the issuance of shares to all eligible employees of the Company at a discounted price. Government Subsidies Government subsidies are recognized where there is reasonable assurance that the subsidy will be received and all attached conditions will be complied with. When the subsidy relates to an expense item, it is recognized as income on a systematic basis over the periods that the related costs, for which it is intended to compensate, are expensed. When the subsidy relates to an asset, it is recognized as income in equal amounts over the expected useful life of the related asset. When the subsidy does not relate to specific expenses or assets, the income is accounted for in the period where there is reasonable assurance that the subsidy will be received. Income Taxes The Company utilizes the asset and liability method of accounting for income taxes, under which deferred taxes are determined based on the temporary differences between the financial statement and tax basis of assets and liabilities using tax rates expected to be in effect during the years in which the basis differences reverse. Deferred income taxes arise from temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements, which will result in taxable or deductible amounts in the future. In evaluating our ability to realize our deferred tax assets within the jurisdiction from which they arise, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax-planning strategies, and results of recent operations. In projecting future taxable income, we begin with historical results and incorporate assumptions about the amount of future federal, state, and foreign pretax operating income adjusted for items that do not have tax consequences. The assumptions about future taxable income require significant judgment and are consistent with the plans and estimates we are using to manage the underlying businesses. In evaluating the objective evidence that historical results provide, we consider recent cumulative income (loss). A valuation allowance is recorded when it is more likely than not that some of the deferred tax assets will not be realized. Income tax positions must meet a more likely than not recognition threshold to be recognized. The Company recognizes tax benefits from uncertain tax positions only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such positions are then measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company recognizes potential accrued interest and penalties related to unrecognized tax benefits within the consolidated statements of income as income tax expense. The Company accounts for Global Intangible Low-Taxed Income (“GILTI”) as period costs when incurred. Net Income per Share Basic net income per share is computed by dividing net income by the weighted average number of shares outstanding for the period. Diluted net income per share is calculated by dividing net income by the weighted average number of common shares outstanding and common equivalent shares from dilutive stock options and restricted stock using the treasury stock method, except when such shares are anti-dilutive. See Note 14 to the Notes to Consolidated Financial Statements. Business Combinations The Company recognizes assets acquired (including goodwill and identifiable intangible assets), liabilities assumed and noncontrolling interest at fair value on the acquisition date. Subsequent changes to the fair value of such assets acquired and liabilities assumed are recognized in earnings, after the expiration of the measurement period, a period not to exceed 12 months from the acquisition date. Acquisition-related expenses and acquisition-related restructuring costs are recognized in earnings in the period in which they are incurred. Accounting Standard Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financing Reporting. Although there are several other new accounting pronouncements issued by the FASB, the Company does not believe any of these accounting pronouncements had or will have a material impact on its Consolidated Financial Statements.

Business Combinations

Business Combinations	12 Months Ended
	Dec. 25, 2020
Business Combinations [Abstract]
Business Combinations	2. BUSINESS COMBINATIONS Dynamic Manufacturing Solutions, LLC On April 15, 2019, the Company purchased substantially all of the assets of DMS, a semiconductor weldment and solutions provider based in Austin, Texas. Pursuant to the purchase agreement, the former owners of DMS are entitled to receive up to $12.5 million of potential cash earn-out if the combined weldment business, after the acquisition, achieves certain gross profit and gross margin targets for the twelve months ending June 26, 2020. The fair value of the earn-out at the acquisition date was $1.5 million and was determined using a risk adjusted earnings projection utilizing the Monte Carlo Simulation model. These inputs are not observable in the market and thus represent a Level 3 measurement as discussed in Note 4 of the Company’s Consolidated Financial Statements. The total purchase consideration of DMS for purposes of the Company’s purchase price allocation was determined to be $31.4 million, which includes the cash payment of $29.9 million and the fair value of the potential earn-out payments of approximately $1.5 million. During the second quarter of fiscal year 2020, DMS achieved the specified performance target of the earn-out, which resulted in the maximum payment of $12.5 million in August 2020. The increases in fair value of $3.0 and $8.0 million during fiscal 2020 and 2019, respectively, were recorded as other expense in the consolidated statement of operations. In the first quarter of fiscal year 2020, the Company completed the acquisition accounting and the valuation of the fair value of the assets acquired and the liabilities assumed. The following table summarizes the recognized amounts of assets acquired and liabilities assumed at the date of acquisition: Fair Market Values (In millions) Accounts receivable $ 1.5 Inventories 8.9 Property, plant and equipment 5.4 Goodwill 12.3 Intangible assets 6.9 Other assets 0.3 Total assets acquired 35.3 Accounts payable (3.8 ) Other liabilities (0.1 ) Total liabilities assumed (3.9 ) Purchase price allocated $ 31.4 The customer relationships intangible assets acquired from the acquisition of DMS has an estimated useful life of six years. The results of operations for the Company for fiscal year ended included eight months of operating activities for DMS. Net sales of approximately $35.2 million and operating income of approximately $4.9 million attributable to DMS were included in the consolidated results of operations. For the fiscal year ended , results of operations included charges of $8.0 million of contingent earn-out expense recorded in other income (expense), net, $0.8 million attributable to amortization of intangible assets and $1.2 million of deal costs associated with the acquisition. Pro Forma Consolidated Results The following unaudited pro forma consolidated results of operations assume the DMS acquisition was completed as of the beginning of the 2019 fiscal year. Unaudited Pro Forma Information Year Ended December 27, 2019 (In millions, except per share amounts) Revenues $ 1,075.4 Net loss $ (8.0 ) Basic loss per share $ (0.20 ) Diluted loss per share $ (0.20 ) The unaudited pro forma results above include adjustments related to the purchase price allocation and financing of the acquisition, primarily to increase amortization for the identifiable intangible assets, to increase interest expense for the additional debt incurred to complete the acquisition and to reflect the related income tax effect. The unaudited pro forma condensed combined financial information has been prepared by management for illustrative purposes only and are not necessarily indicative of the consolidated financial position or results of operations in future periods or the results that would have been realized had UCT and DMS been a combined company during the specified period. The unaudited pro forma condensed combined financial information does not reflect any operating efficiencies and/or cost savings that the Company may achieve with respect to the combined companies, or any liabilities that may result from integration activities.

Balance Sheet Information

Balance Sheet Information	12 Months Ended
	Dec. 25, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Balance Sheet Information	3. BALANCE SHEET INFORMATION Inventories consisted of the following: December 25, December 27, (In millions) 2020 2019 Raw materials $ 102.9 $ 99.9 Work in process 64.5 57.6 Finished goods 13.0 14.9 Total $ 180.4 $ 172.4 At December 25, 2020 and December 27, 2019, inventory balances were $180.4 million and $172.4 million, respectively, net of reserves of $12.0 million for both fiscal years. The inventory write-downs are recorded as an inventory valuation allowance established on the basis of obsolete inventory or specific identified inventory in excess of estimated usage. For fiscal years 2020, 2019 and 2018, inventory write-downs were $3.4 million, $2.5 million and $3.3 million, respectively. Property, plant and equipment, net, consisted of the following: Useful Life December 25, December 27, (In millions) (in years) 2020 2019 Land n/a $ 3.8 $ 4.8 Buildings 50 37.2 36.9 Leasehold improvements * 46.7 41.8 Machinery and equipment 5-10 73.8 58.1 Computer equipment and software 3-10 42.5 32.1 Furniture and fixtures 5 4.4 4.4 208.4 178.1 Accumulated depreciation (84.0 ) (56.7 ) Construction in progress 34.8 23.9 Total $ 159.2 $ 145.3 * Lesser of estimated useful life or remaining lease term Restructuring During the first quarter of fiscal year 2020, the Company made a strategic decision to fully integrate Quantum Global Technologies, LLC’s (“QGT”) corporate office responsibilities from Quakertown, PA to UCT’s corporate office in Hayward, CA. As a result, the Company recorded a restructuring charge of $1.9 million for the fiscal year ended December 25, 2020, in general and administrative expense, primarily related to employee severance as well as the impaired value of the facility lease and losses on sale of equipment. During the fourth quarter of fiscal year 2019, the Company made a strategic decision to close its machining operations in South San Francisco, CA. As a result, the Company recorded a restructuring charge of $12.6 million for fiscal year ended December 27, 2019, in general and administrative expense, related to the sale of equipment, facility leases, severance and write down of inventory.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 25, 2020
Fair Value Disclosures [Abstract]
Fair Value	4. FAIR VALUE The fair value hierarchy requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. The following table summarizes, for assets or liabilities measured at fair value, the respective fair value and the classification by level of input within the fair value hierarchy: Fair Value Measurement at Reporting Date Using Description December 25, 2020 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In millions) Other assets: Forward contracts $ 1.1 $ — $ 1.1 $ — Other liabilities: Common stock purchase obligation $ 12.6 $ — $ — $ 12.6 Pension obligation $ 4.7 $ — $ — $ 4.7 Fair Value Measurement at Reporting Date Using Description December 27, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In millions) Other liabilities: Contingent earn-out liability $ 9.5 $ — $ — $ 9.5 Common stock purchase obligation $ 6.8 $ — $ — $ 6.8 Pension obligation $ 4.4 $ — $ — $ 4.4 The estimated fair value of foreign currency forward contracts is based upon quoted market prices obtained from independent pricing services for similar derivative contracts and these financial instruments are characterized as Level 2 assets in the fair value hierarchy. The estimated fair value of common stock purchase obligation is based on a combination of an income and market valuation approach. The income and market valuation approaches may incorporate Level 3 fair value measures for instances when observable inputs are not available. The more significant judgmental assumptions used to estimate the value of common stock purchase obligation include an estimated discount rate, a range of assumptions that form the basis of the expected future net cash flows (e.g., the revenue growth rates and operating margins), and a company specific beta. The significant judgmental assumptions used that incorporate market data, including the relative weighting of market observable information and the comparability of that information in the valuation models, are forward-looking and could be affected by future economic and market conditions. The estimated fair value of pension obligation is based on expected years of service and average compensation. The valuation model used to value pension obligation utilizes mortality rate, inflation, interest rate risks and changes in the life expectancy for pensioners. These assumptions are routinely made in the appraisal process by the independent actuary thus resulted in a Level 3 classification. There were no transfers from Level 1 or Level 2. Fair value adjustments were noncash, and therefore did not impact the Company’s liquidity or capital resources. Qualitative information about Level 3 fair value measurements is as follow: (Dollars in millions, except rate/multiple) December 25, 2020 Valuation Techniques Unobservable Input Rate/Multiple Common stock purchase obligation $ 12.6 Discounted cash flow Revenue Multiple 1.3 - 2.0 EBITDA Multiple 5.5 - 7.4 Discount rate 15.50% - 20.00% Pension obligation $ 4.7 Projected unit credit method Discount rate 2.10 % Rate on return 1.10 % Salary increase rate 4.00 % Following is a summary of the Level 3 activity: (In millions) Contingent earn-out liability Common stock purchase obligation Pension obligation As of December 27, 2019 $ 9.5 $ 6.8 $ 4.4 Fair value adjustments (DMS) 3.0 - - Fair value adjustments (QGT) - 5.8 - Benefits, payments and other adjustments (12.5 ) - 0.3 As of December 25, 2020 $ - $ 12.6 $ 4.7

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 25, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	5. GOODWILL AND INTANGIBLE ASSETS The Company’s methodology for allocating the purchase price relating to an acquisition is determined through established and generally accepted valuation techniques. Goodwill is measured as the excess of the consideration transferred over the sum of the amounts assigned to tangible and identifiable intangible assets acquired less liabilities assumed. Goodwill and purchased intangible assets with indefinite useful lives are not amortized, but are reviewed for impairment at least annually and whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. To test goodwill for impairment, the Company first performs a qualitative assessment to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If the Company concludes it is more likely than not that the fair value of a reporting unit exceeds its carrying amount, the Company does not proceed to perform a quantitative impairment test. If the Company concludes it is more likely than not that the fair value of the reporting unit is less than its carrying value, a quantitative goodwill impairment test will be performed by comparing the fair value of each reporting unit to its carrying value. A quantitative impairment analysis, if necessary, considers the income approach, which requires estimates of the present value of expected future cash flows to determine a reporting unit’s fair value. Significant estimates include revenue growth rates and operating margins used to calculate projected future cash flows, discount rates, and future economic and market conditions. A goodwill impairment charge is recognized for the amount by which the reporting unit’s fair value is less than its carrying value. Any loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. In the fourth quarters of 2020 and 201 9 , the Company conducted its annual impairment tests of goodwill and concluded that there was no goodwill impairment with respect to its reporting units. Details of aggregate goodwill of the Company are as follows: (In millions) Products Services Total Balance at December 27, 2019 $ 97.6 $ 73.5 $ 171.1 Business combination - - - Balance at December 25, 2020 $ 97.6 $ 73.5 $ 171.1 Intangible Assets Intangible assets are generally recorded in connection with a business acquisition. The Company evaluates the useful lives of its intangible assets each reporting period to determine whether events and circumstances require revising the remaining period of amortization. In addition, the Company reviews indefinite lived intangible assets for impairment when events or changes in circumstances indicate their carrying value may not be recoverable and tests definite lived intangible assets at least annually for impairment. Management considers such indicators as significant differences in product demand from the estimates, changes in the competitive and economic environment, technological advances, and changes in cost structure. Details of intangible assets were as follows: As of December 25, 2020 As of December 27, 2019 Gross Gross Useful Life Carrying Accumulated Carrying Carrying Accumulated Carrying (Dollars in millions) (in years) Amount Amortization Value Amount Amortization Value Customer relationships 6 - 10 $ 119.4 $ (50.6 ) $ 68.8 $ 119.4 $ (39.8 ) $ 79.6 Tradename 4 - 6* 27.0 (11.7 ) 15.3 27.0 (8.1 ) $ 18.9 Intellectual property/know-how 7 - 12 13.9 (9.8 ) 4.1 13.9 (8.4 ) $ 5.5 Recipes 20 73.2 (8.5 ) 64.7 73.2 (4.9 ) $ 68.3 Standard operating procedures 20 8.6 (1.0 ) 7.6 8.6 (0.6 ) $ 8.0 Total $ 242.1 $ (81.6 ) $ 160.5 $ 242.1 $ (61.8 ) $ 180.3 * The concluded that the asset life of UCT tradename of $9.0 million is indefinite and is therefore not amortized but is reviewed for impairment at least annually and whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable. Amortization expense was approximately $19.8 million for the year ended December 25, 2020, $20.1 million for the year ended December 27, 2019, and $9.6 million for the year ended December 28, 2018. Amortization (In millions) Expense 2021 $ 19.6 2022 19.3 2023 14.2 2024 14.0 2025 12.3 Thereafter 72.1 Total $ 151.5

Borrowing Arrangements

Borrowing Arrangements	12 Months Ended
	Dec. 25, 2020
Debt Disclosure [Abstract]
Borrowing Arrangements	6. BORROWING ARRANGEMENTS In August 2018, the Company entered into a credit agreement with Barclays Bank that provided a Term Loan, a Revolving Credit Facility, and a Letter of Credit Facility (the “Credit Facility”). UCT and certain of its subsidiaries have agreed to secure all of their obligations under the Credit Facility by granting a first priority lien in substantially all of their respective personal property assets (subject to certain exceptions and limitations). In August 2018 , the Company borrowed $ 350.0 million under the Term Loan and used the proceeds, together with cash on hand, to finance the acquisition of QGT and t o refinance its previous credit facilities. The Term Loan has a maturity date of August 27, 2025, with monthly interest payments in arrears, quarterly principal payments of 0.625% of the original outstanding principal balance payable beginning in January 2019, with the remaining principal paid upon maturity. The Term Loan accrues interest at a rate equal to a base LIBOR rate determined by reference to the London interbank offered rate for dollars, plus 4.5% (subject to certain adjustments quarterly based upon the Company’s consolidated leverage ratio). At December 25, 2020, the Company had an outstanding amount under the Term Loan of $275.0 million, gross of unamortized debt issuance costs of $7.9 million. The Revolving Credit Facility has an initial available commitment of $65.0 million and a maturity date of August 27, 2023. The Company pays a quarterly commitment fee in arrears equal to 0.25% of the average daily available commitment outstanding. The Credit Agreement requires the Company to maintain certain financial covenants including a consolidated fixed charge coverage ratio (as defined in the Credit Agreement) as of the last day of any fiscal quarter of at least 1.25 to 1.00, and a consolidated leverage ratio (as defined in the Credit Agreement) as of the last day of any fiscal quarter of no greater than 3.75 to 1.00. The Company was in compliance with all financial covenants during the year ended December 25, 2020. The Letter of Credit Facility has an initial available commitment of $50.0 million and a maturity date of August 27, 2023. The Company pays quarterly in arrears a fee equal to 2.5% (subject to certain adjustments as per the Term Loans) of the dollar equivalent of all outstanding letters of credit, and a fronting fee equal to 0.125% of the undrawn and unexpired amount of each letter of credit. As of December 25, 2020, the Company had $2.4 million of outstanding letters of credit and remaining available commitment of $47.6 million on the Letter of Credit Facility and $65.0 million on the Revolving Credit Facility. As of December 25, 2020, FDS had no outstanding amount under a revolving credit facility. In 2020, Cinos China amended its existing Credit Agreement and entered into two additional Credit Agreements with a local bank that provide Revolving Credit Facilities for a total available commitment of $3.5 million with various maturity dates through September 23, 2022 and interest rates ranging from 1.9% to 4.1%. As of December 25, 2020, Cinos China had an outstanding amount of $ 1.9 million with an interest rates of 2.1% to 4.1% under these Credit Agreements. Cinos Korea has Credit Agreements with various banks that provide Revolving Credit Facilities for a total available commitment of 1.6 billion Korean Won (approximately $1.4 million) with annual renewals beginning from April 2021 through June 2021 and interest rates ranging from 1.4% - 5.4% fiscal 2020 December 25, 2020 FDS has a credit agreement with a local bank in the Czech Republic that provides for a revolving credit facility in the aggregate of up to 6.0 million euros. As of December 25, 2020, the Company had no amount outstanding under this revolving credit facility. As of December 25, 2020, the Company’s total bank debt was $269.0 million, net of unamortized debt issuance costs of $7.9 million. As of December 25, 2020, the Company had $55.0 million, $1.0 million and $1.5 million available to draw from its revolving credit facilities in the U.S., Czech Republic and China, respectively. The fair value of the Company’s long-term debt was based on Level 2 inputs, and fair value was determined using quoted prices for similar liabilities in inactive markets. The Company’s carrying value approximates fair value for the Company’s long term-debt. As of December 25, 2020, the Company’s future debt principal payment obligations for the respective fiscal years were as follows: Debt (In millions) (Principal only) 2021 $ 9.2 2022 9.0 2023 9.9 2024 8.8 2025 8.7 Thereafter 231.3 Total $ 276.9

Income Taxes

Income Taxes	12 Months Ended
	Dec. 25, 2020
Income Tax Disclosure [Abstract]
Income Taxes	7. INCOME TAXES The provision for income taxes consisted of the following: Year Ended December 25, December 27, December 28, (In millions) 2020 2019 2018 Current: Federal $ (0.1 ) $ 0.1 $ 2.3 State 0.9 0.1 0.7 Foreign 18.1 12.3 12.2 Total current 18.9 12.5 15.2 Deferred: Federal 0.3 (0.1 ) 0.2 State 0.5 0.7 0.1 Foreign (0.4 ) (3.1 ) (0.2 ) Total deferred 0.4 (2.5 ) 0.1 Total provision $ 19.3 $ 10.0 $ 15.3 Income before provision for income taxes was generated from the following geographic areas: Year Ended December 25, December 27, December 28, (In millions) 2020 2019 2018 United States $ (24.5 ) $ (49.7 ) $ (5.0 ) Foreign 124.2 52.0 57.3 Total pretax income $ 99.7 $ 2.3 $ 52.3 The effective tax rate differs from the U.S. federal statutory tax rate as follows: Year Ended December 25, December 27, December 28, 2020 2019 2018 Federal income tax provision at statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit 0.6 % (99.5 ) % 2.0 % Effect of foreign operations (8.3 ) % (85.3 ) % — % Change in valuation allowance (0.1 ) % 552.7 % (0.1 ) % Foreign income inclusions 4.6 % 34.5 % 2.1 % Adjustment for changes in tax law — % — % 3.6 % Common stock purchase obligation 1.2 % — % — % Income tax audit adjustment 1.3 % — % — % Other (1.0 ) % (7.5 ) % 0.7 % Effective Tax Rate 19.3 % 415.9 % 29.3 % Significant components of deferred tax assets and liabilities are as follows: Year Ended December 25, December 27, (In millions) 2020 2019 Deferred tax assets: Inventory valuation and basis difference $ 3.9 $ 3.4 State taxes 0.2 0.5 Stock compensation 1.7 1.7 Operating lease liabilities 10.0 9.0 Interest expense limitation 6.8 5.8 Intangibles 12.6 7.8 Net operating losses 6.4 6.4 Tax credits 2.6 2.2 Other timing differences 4.9 4.5 49.1 41.3 Valuation allowance (25.6 ) (25.8 ) Total deferred tax assets 23.5 15.5 Deferred tax liabilities: Undistributed earnings (0.5 ) (0.5 ) Operating lease right-of-use assets (8.5 ) (7.2 ) Depreciation (5.0 ) (3.3 ) Intangibles (6.7 ) (5.8 ) Goodwill (12.9 ) (8.4 ) Total deferred tax liabilities (33.6 ) (25.2 ) Net deferred tax liabilities $ (10.1 ) $ (9.7 ) The Company provides for U.S. income taxes on the earnings of its foreign subsidiaries to the extent required by the Tax Cuts and Jobs Act ( undistributed earnings is needed than the previous anticipated remaining unremitted foreign earnings, the Company could be required to accrue or pay foreign taxes on some or all of these undistributed earnings. As of December 25, 2020 , the Company had undistributed earnings of foreign subsidiaries that are considered indefinitely invested outside of the U.S. of approximately $ 267.2 million. It is not practicable to determine the tax liability that might be incurred if these earnings were to be distributed. The Company’s gross liability for unrecognized tax benefits as of December 25, 2020 and December 27, 2019 was $0.9 million and $1.0 million, respectively. Increases or decreases to interest and penalties on uncertain tax positions are included in the income tax provision in the Consolidated Statements of Operations. Interest related to uncertain tax positions for the periods ended December 25, 2020, December 27, 2019 and December 28, 2018 were $0.3 million, $0.3 million, and $0.1 million, respectively. Although it is possible some of the unrecognized tax benefits could be settled within the next twelve months, the Company cannot reasonably estimate the outcome at this time. The following Balance as of December 29, 2017 $ 0.3 Increases related to current year positions 0.7 Expiration of the statute of limitations - Balance as of December 28, 2018 $ 1.0 Increases related to current year tax positions - Expiration of the statute of limitations for the assessment of taxes - Balance as of December 27, 2019 $ 1.0 Increases related to current year tax positions - Expiration of the statute of limitations for the assessment of taxes (0.1 ) Balance as of December 25, 2020 $ 0.9 As of December 25, 2020, the Company had California net operating loss carryforwards (“NOLs”) of approximately $35.8 million. The California NOLs begins expiring after 2031. On March 27, 2020, the previous U.S. President signed into law the Coronavirus Aid, Relief, and Economic Security Act (the CARES Act) in response to the U.S. COVID-19 pandemic, which, among other things, suspends the 80% limitation on the deduction for NOLs in taxable years beginning before January 1, 2021, permits a 5-year carryback of NOLs arising in taxable years beginning after December 31, 2017 and before January 1, 2021, and generally caps the limitation on the deduction for net interest expense at 50% of adjusted taxable income for taxable years beginning in 2019 and 2020. In addition, the CARES Act raises the corporate charitable deduction limit to 25% of taxable income and makes qualified improvement property generally eligible for 15-year cost-recovery and 100% bonus depreciation. The enactment of the CARES Act did not result in any material adjustments to the Company's income tax provision for the year ended December 31, 2020, or to its net deferred tax assets and related allowances as of December 31, 2020. The Company files federal, state and foreign income tax returns in several U.S. and foreign jurisdictions. The federal statute of limitation has closed for years prior to 2017. State statutes of limitation are generally closed for years prior to 2016. The statute of limitation for significant foreign jurisdictions has closed for years prior to 2017. During the fiscal quarter ended December 25, 2020, the Company recorded a net charge to provision for income taxes of approximately $1.3 million related to the settlement of an income tax audit by the local tax authorities of Cinos Korea. The net settlement reflects additional taxes and associated penalties for the tax years 2015 – 2019. The Company has operated under a Development and Expansion Incentive (“DEI”) in Singapore that ended on December 25, 2020. However, the Company has reached an agreement in principle with the Singapore Economic Development Board for an extension of the DEI through 2023. The DEI will reduce the local tax on certain Singapore income from a statutory rate of 17.0% to 5.0%.

Retirement Plans

Retirement Plans	12 Months Ended
	Dec. 25, 2020
Compensation And Retirement Disclosure [Abstract]
Retirement Plans	8. RETIREMENT PLANS Defined Benefit Plan Cinos Korea has a noncontributory defined benefit pension plan covering substantially all of its employees upon their retirement. The benefits are based on expected years of service and average compensation. The net period costs are recognized as employees render the services necessary to earn the postretirement benefits. The Company records annual amounts relating to the pension plan based on calculations that incorporate various actuarial and other assumptions, including discount rates, mortality, assumed rates of return, compensation increases and turnover rates. The Company reviews its assumptions on an annual basis and makes modifications to the assumptions based on current and expected rates of return and trends when it is appropriate to do so. The effect of modifications to those assumptions is recorded in accumulated other comprehensive income and amortized to net periodic cost over future periods using the corridor method. The Company believes that the assumptions utilized in recording its obligations under the plan are reasonable based on its experience and market conditions. As of December 25, 2020, the benefit obligation of the plan is $9.7 million and the fair value of the benefit plan assets, which are invested in several fixed deposit accounts with a bank is $6.7 million. As of December 25, 2020, the unfunded balance of the plan of $3.0 million has been accrued for by the Company and is included in other long-term liabilities. Amounts recognized in accumulated other comprehensive income as of December 25, 2020 and December 27, 2019 was $0.5 and $1.7 million, respectively. The contributions to the plan by the Company and its subsidiaries during the year ended December 25, 2020 was $2.8 million. The benefits expected to be paid from the pension plan in each year from 2021-2025 are $0.9 million, $1.0 million, $2.3 million $1.0 million and $1.0 million, respectively. The aggregate benefits expected to be paid in the five years from 2026-2031 are $5.9 million. Employee Savings and Retirement Plan The Company sponsors a 401(k) savings and retirement plan (the “401(k) Plan”) for all US employees who meet certain eligibility requirements. Participants could elect to contribute to the 401(k) Plan, on a pre-tax basis, up to 25.0% of their salary to a maximum of the IRS limit. The Company matches 50.0% of participant salary up to 6.0% of employee contributions based upon eligibility. The Company made discretionary employer contributions of approximately $2.4 million, $2.3 million and $1.2 million to the 401(k) Plan in 2020, 2019 and 2018, respectively.

Commitments and Contingencies

Commitments and Contingencies	12 Months Ended
	Dec. 25, 2020
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingencies	9. COMMITMENTS AND CONTINGENCIES Commitment The Company had commitments to various third parties to purchase inventories totaling approximately $205.9 million at December 25, 2020 Contingency From time to time, the Company is subject to various legal proceedings and claims, either asserted or unasserted, that arise in the ordinary course of business. Although the outcome of the various legal proceedings and claims individually or in the aggregate cannot be predicted with certainty, the Company has not had a history of outcomes to date that have been material to the statement of operations and does not believe that any of these proceedings or other claims will have a material adverse effect on its consolidated financial condition, results of operations or cash flows.

Stockholders' Equity and Noncon

Stockholders' Equity and Noncontrolling Interests	12 Months Ended
	Dec. 25, 2020
Noncontrolling Interest [Abstract]
Stockholders' Equity and Noncontrolling Interests	10. STOCKHOLDERS’ EQUITY AND NONCONTROLLING INTERESTS Noncontrolling Interests QGT, through its wholly-owned subsidiary in Singapore, owns 51.0% of the outstanding shares of Cinos Korea, a South Korean company that provides outsourced cleaning and recycling of precision parts for the semiconductor industry through its operating facilities in South Korea and through a 60.0% interest in Cinos China. QGT is obligated to purchase shares held by another shareholder of Cinos Korea representing a 35.0% interest in Cinos Korea. QGT accounted for this unconditional obligation as an assumed liability and derecognized any noncontrolling interest related to the 35%, which brings its controlling interest up to 86%. The carrying value of the remaining 14.0% interest held by another shareholder in Cinos Korea and the 40.0% interest in Cinos China are presented as noncontrolling interests in the accompanying Consolidated Financial Statements. The fair values of the noncontrolling interests were estimated based on the values of Cinos Korea and Cinos China on a 100.0% basis. The values were calculated based on the pro-rata portion of total QGT earnings before interest expense, taxes, depreciation and amortization ("EBITDA") contributed by each entity. The Company is obligated to purchase shares owned by a Cinos Korea shareholder. A certain number of shares would be purchased at a fixed price per share, while the other remaining shares would be purchased based on the greater of the then fair value of the stock and the fixed price per share (floor). The Company has a firm obligation to purchase the shares and a call option, while the other shareholder has a put option. As of December 25, 2020, the fair value of the obligation of $12.6 million which has been recorded as a non-current liability in the accompanying consolidated balance sheets and represents a Level 3 measurement as discussed in Note 4 of the Company’s Consolidated Financial Statements. The agreement with Cinos Korea allows for the common stock purchase obligation to become due in December 2022, and once completed, the Company will own 86.0% of Cinos Korea.

Employee Stock Plans

Employee Stock Plans	12 Months Ended
	Dec. 25, 2020
Postemployment Benefits [Abstract]
Employee Stock Plans	11. EMPLOYEE STOCK PLANS Employee Stock Plans The Company maintains plans which allow for the issuance of equity-based awards to executives and certain employees. These equity-based awards include stock options, restricted stock awards (RSAs), performance stock units (PSUs) and restricted stock units (RSUs). The Company also maintains an employee stock purchase plan (“ESPP”) that provides for the issuance of shares to all eligible employees of the Company at a discounted price. The estimated fair value of the Company’s equity-based awards, net of expected forfeitures, is amortized over the awards’ vesting period on a straight-line basis over a weighted average period of four years for stock options, three years for PSUs and RSUs and one year for RSAs and will be adjusted for subsequent changes in estimated forfeitures and future option grants. The Company uses historical data to estimate pre-existing forfeitures, and records stock-based compensation for those awards that are expected to vest at the time of grant and revises those estimates in subsequent periods if actual forfeitures differ from those estimates. During fiscal years 2020, 2019 and 2018, the Company recorded $12.7 million, $12.1 million and $10.3 million, respectively, of stock-based compensation expense, associated with the 2003 Incentive Plan. As of December 25, 2020, there was $16.4 million, net of forfeitures of $2.5 million, of unrecognized compensation cost related to employee and director stock which is expected to be recognized on a straight-line basis over a weighted average period of approximately 1.6 years, and will be adjusted for subsequent changes in estimated forfeitures and future grants. Total stock-based compensation during the fiscal years 2020, 2019 and 2018, respectively, in various expense categories was as follows: Year Ended December 25, December 27, December 28, (In millions) 2020 2019 2018 Cost of revenues (1) $ 1.8 $ 2.4 $ 2.1 Research and development 0.1 0.3 0.1 Sales and marketing 1.3 1.3 1.0 General and administrative 9.5 8.1 7.1 12.7 12.1 10.3 Income tax benefit (2.5 ) — (3.0 ) Net stock-based compensation expense $ 10.2 $ 12.1 $ 7.3 (1) Stock-based compensation expenses capitalized in inventory for fiscal years 2020, 2019 and 2018 were considered immaterial. 2003 Amended and Restated Stock Incentive Plan Options The 2003 Incentive Plan provides for the issuance of options and other stock-based awards. Options are generally granted at fair value at the date of grant as determined by the Board of Directors and have terms up to ten years and generally vest over four years. There was no stock-based compensation expense for fiscal year 2020, 2019 and 2018 attributable to stock options and no outstanding options as of December 25, 2020. Restricted Stock Units and Restricted Stock Awards In fiscal years 2020, 2019 and 2018, the Company granted 46,363, 69,783 and 38,010 shares, respectively, of common stock to its board members under the 2003 Incentive Plan. These RSAs vest on the earlier of 1) the next Annual Shareholder Meeting, or 2) 365 days from date of grant. The total unamortized expense of the Company’s unvested RSAs as of December 25, 2020, is approximately $0.4 million. RSUs and PSUs are granted to employees with a unit purchase price of zero dollars and typically vest over three years, subject to the employee’s continued service with the Company and, in the case of PSUs, subject to achieving certain performance goals. The expected cost of the grant is recognized over the service period, and is reduced for estimated forfeitures and, in the case of PSUs, is reduced based on estimated achievement of performance goals. During the year ended December 25, 2020, the Company approved and granted 694,066 RSU’s to employees with a weighted average grant date fair value of $19.07 per share and 148,816 PSUs with a weighted average grant date fair value of $15.27 per share. As of December 25, 2020, $16.0 million of unrecognized stock-based compensation cost, net of estimated forfeitures, related to RSUs and PSUs remains to be amortized and is expected to be recognized over an estimated period of 1.6 years. The unvested amount is subject to forfeiture, until fully vested. At December 25, 2020, 1,665,987 shares were subject to forfeiture. The following table summarizes the Company’s PSUs, RSUs and RSAs activities through the year ended December 25, 2020 Aggregate Intrinsic Number of Value Shares (in millions) Unvested restricted stock units and restricted stock awards at December 28, 2018 1.8 $ 14.6 Granted 1.1 Vested (0.9 ) Forfeited (0.2 ) Unvested restricted stock units and restricted stock awards at December 27, 2019 1.8 $ 41.9 Granted 0.9 Vested (0.8 ) Forfeited (0.2 ) Unvested restricted stock units and restricted stock awards at December 25, 2020 1.7 $ 54.1 Vested and expected to vest restricted stock units and restricted stock awards 1.7 $ 54.1 Employee Stock Purchase Plan The ESPP permits employees to purchase common stock at a discount through payroll withholdings at certain specified dates (purchase period) within a defined offering period. The purchase price is 95% of the fair market value of the common stock at the end of the purchase period and is intended to qualify as an “employee stock purchase plan” under Section 423 of the Internal Revenue Code. There were 29,143 shares issued under the ESPP during the year ended December 25, 2020

Revenue Recognition

Revenue Recognition	12 Months Ended
	Dec. 25, 2020
Revenue From Contract With Customer [Abstract]
Revenue Recognition	12. REVENUE RECOGNITION Revenue is recognized when control of the promised goods or services is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company sells its products and services primarily to customers in the semiconductor capital equipment industry. The Company’s revenues are highly concentrated, and we are therefore highly dependent upon a small number of customers. Typical payment terms with our customers range from thirty to sixty days. The Company’s Products business segment provides warranty on its products for a period of up to two years and provides for warranty costs at the time of sale based on historical activity. Determination of the warranty reserve requires the Company to make estimates of product return rates and expected costs to repair or replace the products under warranty. If actual return rates and/or repair and replacement costs differ significantly from these estimates, adjustments to recognize additional cost of revenues may be required in future periods. The warranty reserve is included in other current liabilities on the Consolidated Balance Sheets and are not considered significant. The Company’s products are manufactured at our facilities in the U.S.A., China, Singapore and the Czech Republic. The Company provides services from operations in the U.S.A., Singapore, United Kingdom, Israel, Taiwan, South Korea, and China. Sales to customers are initiated through a purchase order and are governed by our standard terms and conditions, written agreements, or both. Revenue is recognized when performance obligations under the terms of an agreement with a customer are satisfied; generally, this occurs with the transfer of control of the products or when the Company provides the services. Transfer of control occurs at a specific point-in-time. Based on the enforceable rights included in our agreements or prevailing terms and conditions, products produced by the Company without an alternative use are not protected by an enforceable right of payment that includes a reasonable profit throughout the duration of the agreement. Consignment sales are recognized in revenue at the earlier of the period that the goods are consumed or after a period of time subsequent to receipt by the customer as specified by terms of the agreement, provided control of the promised goods or services has transferred. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services. Sales, value-add, and other taxes we collect concurrent with revenue-producing activities are excluded from revenue. Certain of our customers may receive cash-based incentives, such as rebates or credits, which are accounted for as variable consideration. We estimate these amounts based on the expected amount to be provided to customers and reduce revenues recognized. As of December 25, 2020, an accrual for unpaid customer rebates of $3.4 million is included in accounts receivable on the Company’s Consolidated Balance Sheet. The Company's disaggregated revenues are by segments. The Company’s principal markets include America, Asia and Europe. The Company’s foreign operations are conducted primarily through its subsidiaries in China, Singapore, Israel, Taiwan, South Korea, United Kingdom and the Czech Republic. Revenues by geographic area are categorized based on the customer’s location to which the products were shipped or services performed. The following table sets forth revenue by geographic area (in millions): Year Ended December 25, December 27, December 28, 2020 2019 2018 United States $ 613.7 $ 546.2 $ 602.2 Singapore 494.4 302.1 315.3 Korea 83.7 68.2 45.6 Austria 57.4 47.7 58.1 Taiwan 68.1 44.4 22.6 China 47.7 35.3 42.1 Others 33.6 22.3 10.6 Total $ 1,398.6 $ 1,066.2 $ 1,096.5

Leases

Leases	12 Months Ended
	Dec. 25, 2020
Leases [Abstract]
Leases	13. LEASES The Company leases offices, facilities and equipment in locations throughout the United States, Asia and Europe. The Company’s leases do not provide an implicit rate; thus, the Company uses an estimated incremental borrowing rate in determining the present value of lease payments. The components of lease expense were summarized as follows: Year Ended (Dollars in millions) December 25, 2020 December 27, 2019 Operating lease cost $ 13.1 $ 13.8 Short-term lease cost 1.3 1.1 Sublease income (0.1 ) (0.2 ) Total lease cost $ 14.3 $ 14.7 Operating cash flows from operating leases $ 16.9 $ 17.3 Weighted-average remaining lease term – operating leases 2.3 2.4 Weighted-average discount rate – operating leases 5.5 % 7.0 % Future minimum payments under operating leases as of December 25, 2020 were summarized as follows: (In millions) Operating Leases 2021 $ 12.8 2022 10.7 2023 7.7 2024 5.4 2025 4.0 Thereafter 8.5 Total minimum lease payments 49.1 Less: imputed interest 6.3 Lease liability $ 42.8 The Company entered into two new lease agreements in fiscal year 2020 with commencement dates in fiscal year 2021. The total minimum lease payments for these two new lease agreements is $22.1 million.

Net Income Per Share

Net Income Per Share	12 Months Ended
	Dec. 25, 2020
Earnings Per Share [Abstract]
Net Income Per Share	14. NET INCOME PER SHARE The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income (loss) per share: Year Ended December 25, December 27, December 28, (In millions, except share amounts) 2020 2019 2018 Numerator: Net income (loss) attributable to UCT $ 77.6 $ (9.4 ) $ 36.6 Denominator: Shares used in computation — basic: Weighted average common shares outstanding 40.2 39.5 38.4 Shares used in computation — diluted: Weighted average common shares outstanding 40.2 39.5 38.4 Dilutive effect of common shares outstanding subject to repurchase 0.9 0.0 0.5 Shares used in computing diluted net income (loss) per share 41.1 39.5 38.9 Net income (loss) per share attributable to UCT — basic $ 1.93 $ (0.24 ) $ 0.95 Net income (loss) per share attributable to UCT — diluted $ 1.89 $ (0.24 ) $ 0.94

Reportable Segments

Reportable Segments	12 Months Ended
	Dec. 25, 2020
Segment Reporting [Abstract]
Reportable Segments	15. REPORTABLE SEGMENTS The Company operates and reports financial results in two operating segments: Products and Services. These segments are organized primarily by the nature of the products and service they provide. The Company’s Chief Executive Officer (chief operating decision maker) views and evaluates operations based on the results of each of the reportable segments. Segment Product or Services Markets Served Geographic Areas Products Assembly Weldments Machining Fabrication Semiconductor United States Asia Europe Services Cleaning Analytics Semiconductor United States Asia Europe The Company uses segment profit or loss as the primary measure of profitability to evaluate operating performance and to allocate capital resources. Segment profit or loss is defined as a segment’s income or loss from continuing operations before other income and income taxes included in the accompanying consolidated statements of operations. Any intercompany sales and associated profit (and any other intercompany items) are eliminated from segment results. There were no significant intercompany eliminations for the periods presented. Fiscal Year End December 25, December 27, December 28, (In millions) 2020 2019 2018 Revenues: Products $ 1,131.2 $ 840.8 $ 1,015.5 Services 267.4 225.4 81 Total segment revenues $ 1,398.6 $ 1,066.2 $ 1,096.5 Gross profit: Products $ 196.5 $ 121.8 $ 150.3 Services $ 95.3 $ 75.0 $ 25.5 Total segment gross profit $ 291.8 $ 196.8 $ 175.8 Operating profit: Products $ 97.2 $ 18.3 $ 52.3 Services 24.2 11.6 8.4 Total segment operating profit $ 121.4 $ 29.9 $ 60.7 December 25, December 27, (In millions) 2020 2019 Assets Products $ 868.4 $ 828.0 Services 234.1 191.3 Total segment assets $ 1,102.5 $ 1,019.3

Government Subsidies

Government Subsidies	12 Months Ended
	Dec. 25, 2020
Government Grants And Subsidies [Abstract]
Government Subsidies	16. GOVERNMENT SUBSIDIES From April through December of the current year, the Singapore government announced a series of relief measures for wages paid to local employees with the purpose of supporting employers during this period of economic uncertainty related to the COVID-19 pandemic, including the co-funding of wages incurred by local employers in fiscal 2020. The Company recorded a total amount $3.1 million subsidies in fiscal 2020. The Company also received unconditional subsidies of $1.5 million from the China government during fiscal 2020. These subsidies were recognized as other income in the consolidated statements of operations. In addition, the China government reduced the cost of certain social insurance requirements and also subsidized rent which benefited the Company by $1.6 million in fiscal 2020. These subsidies were recorded as an offset to cost of revenues and other operating expenses.

Unaudited Quarterly Financial R

Unaudited Quarterly Financial Results	12 Months Ended
	Dec. 25, 2020
Quarterly Financial Information Disclosure [Abstract]
Unaudited Quarterly Financial Results	17. UNAUDITED QUARTERLY FINANCIAL RESULTS The following table sets forth statement of operations data for the periods indicated. The information for each of these periods is unaudited and has been prepared on the same basis as our audited Consolidated Financial Statements included herein and includes all adjustments, consisting only of normal recurring adjustments that we consider necessary for a fair presentation of our unaudited operations data for the periods presented. Historical results are not necessarily indicative of the results to be expected in the future: First Second Third Fourth Fiscal (In million, except per share data) Quarter Quarter Quarter Quarter Year (1) 2020 Revenues $ 320.9 $ 344.8 $ 363.3 $ 369.6 $ 1,398.6 Gross profit $ 65.7 $ 73.9 $ 74.6 $ 77.6 $ 291.8 Net income $ 9.4 $ 21.3 $ 24.4 $ 22.5 $ 77.6 Earnings per share — basic $ 0.24 $ 0.53 $ 0.60 $ 0.56 $ 1.93 Earnings per share — diluted $ 0.23 $ 0.52 $ 0.59 $ 0.55 $ 1.89 2019 Revenues $ 260.1 $ 265.4 $ 254.3 $ 286.4 $ 1,066.2 Gross profit $ 44.8 $ 48.2 $ 47.5 $ 56.3 $ 196.8 Net income (loss) $ 0.6 $ (0.2 ) $ 0.50 $ (10.3 ) $ (9.4 ) Earnings (loss) per share — basic $ 0.02 $ (0.01 ) $ 0.01 $ (0.17 ) $ (0.24 ) Earnings (loss) per share — diluted $ 0.02 $ (0.01 ) $ 0.01 $ (0.17 ) $ (0.24 ) (1) Earnings per share is calculated independently each quarter and for the full year based upon their respective weighted average shares outstanding. Therefore, the sum of the quarterly earnings per share may not equal the annual earnings per share reported.

Organization and Significant _2

Organization and Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 25, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Fiscal Year	Fiscal Year The Company uses a 52-53-week fiscal year ending on the Friday nearest December 31. All references to quarters refer to fiscal quarters and all references to years refer to fiscal years.
Principles of Consolidation	Principles of Consolidation The Company’s Consolidated Financial Statements include the accounts of the Company and its wholly-owned subsidiaries and all intercompany accounts and transactions have been eliminated in consolidation.
Noncontrolling interests	Noncontrolling interests Noncontrolling interests are recognized to reflect
Segments	Segments The Financial Accounting
Foreign Currency Translation and Remeasurement	Foreign Currency Translation and Remeasurement As of December 25, 2020, the functional currency of the Products business unit’s foreign subsidiaries is the U.S. dollar. The functional currency of the Service business unit’s foreign subsidiaries is the local currency except for that of its Singapore and Scotland entities, which is the U.S. dollar. Due to the changes in economic factors in FDS and in S ervices’ entity in Scotland in fiscal 2020 , the Company determined that the functional currency designation of FDS and Services’ entity in Scotland is the U.S. dollar , a change from the functional foreign currency utilized in the prior year. The impact of these changes was not significant. For the Company’s foreign subsidiaries where the local currency is the functional currency, the Company translates the financial statements of these subsidiaries to U.S. dollars using month-end exchange rates for assets and liabilities, and average exchange rates for revenue, costs and expenses. Translation gains and losses are recorded in accumulated other comprehensive income (AOCI) within UCT stockholders’ equity. For the Company’s foreign subsidiaries where the U.S. dollar is the functional currency, any gains and losses resulting from the translation of the assets and liabilities of these subsidiaries are recorded in other income (expense), net.
Use of Estimates	Use of Estimates The presentation U.S. generally accepted accounting principles (“GAAP”)
Cash and Cash Equivalents	Cash and Cash Equivalents The Company considers currency on hand, demand deposits, time deposits, and all highly liquid investments with an original maturity of three months or less at the date of purchase to be cash and cash equivalents. Cash and cash equivalents are held in various financial institutions in the United States and internationally.
Concentration of Credit Risk	Concentration of Credit Risk Financial instruments which subject the Company to concentrations of credit risk consist principally of cash and cash equivalents and accounts receivable. The Company sells its products and provides services primarily to semiconductor capital equipment manufacturers in the United States. The Company performs credit evaluations of its customers’ financial condition and generally requires no collateral. The Company’s most significant customers (having accounted for 10% or more of related) and their related revenues as a percentage of total revenues were as follows: Fiscal Year Ended 2020 2019 2018 Lam Research Corporation 42.9 % 41.7 % 55.1 % Applied Materials, Inc. 24.2 25.2 21.5 Total 67.1 % 66.9 % 76.6 % Three customers’ accounts receivable balances, Lam Research Corporation, Applied Materials, Inc. and ASM International, Inc., were individually greater than 10.0% of accounts receivable as of December 25, 2020 and December 27, 2019, in the aggregate approximately 62.9% and 66.7% of accounts receivable, respectively.
Fair Value of Measurements	Fair Value of Measurements The Company measures its cash equivalents, derivative contracts, contingent earn-out liabilities, pension obligation and common stock purchase obligation at fair value on a recurring basis. Fair value is an exit price, representing the amount that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that is determined based on assumptions that market participants would use in pricing an asset or a liability. Assets and liabilities recorded at fair value are measured and classified in accordance with a three-tier fair value hierarchy based on the observability of the inputs available in the market used to measure fair value: Level 1 — Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets. Level 2 — Inputs that are based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant inputs are observable in the market or can be derived from observable market data. Where applicable, these models project future cash flows and discount the future amounts to a present value using market-based observable inputs including interest rate curves, foreign exchange rates, and credit ratings. Level 3 — Unobservable inputs that are supported by little or no market activities.
Derivative Financial Instruments	Derivative Financial Instruments The Company uses forward contracts to hedge a portion of, but not all, existing and anticipated foreign currency denominated transactions typically expected to occur within 24 months. The purpose of the hedge is to mitigate the effect of exchange rate fluctuations on certain foreign currency denominated costs and eventual cash flows. The Company recognizes derivative instruments as either assets or liabilities in the accompanying Consolidated Balance Sheets at fair value. The Company records changes in the fair value of the derivatives in the accompanying Consolidated Statements of Operations as other income (expense), net, or as a component of AOCI in the accompanying Consolidated Balance Sheets.
Inventories	Inventories Inventories are stated at the lower of cost (which approximates actual cost on a first-in, first-out basis) or net realizable value. The Company evaluates the valuation of all inventories, including raw materials, work-in-process, finished goods and spare parts on a periodic basis. Obsolete inventory or inventory in excess of management’s estimated usage is written down to its estimated market value less costs to sell, if less than its cost. Inherent in the estimates of market value are management’s estimates related to economic trends, future demand for products, and technological obsolescence of the Company’s products. Inventory write downs inherently involve judgments as to assumptions about expected future demand and the impact of market conditions on those assumptions. Although the Company believes that the assumptions it used in estimating inventory write downs are reasonable, significant changes in any one of the assumptions in the future could produce a significantly different result. There can be no assurances that future events and changing market conditions will not result in significant increases in inventory write downs.
Property, Plant and Equipment	Property, Plant and Property, plant and equipment are stated at cost, or, in the case of equipment under finance leases, the present value of future minimum lease payments at inception of the related lease. The Company also capitalizes interest on borrowings related to eligible capital expenditures. Capitalized interest is added to the cost of the qualified assets and is subject to depreciation. Depreciation and amortization are computed using the straight-line method over the lesser of the estimated useful lives of the assets or the terms of the leases. Useful lives range from three to fifty years ten years
Long-lived Assets	Long-lived Assets The Company evaluates long-lived assets At the end of fiscal years 2020, 2019 and 2018, the Company assessed the useful lives of its long-lived assets, including property, plant and equipment as well as its intangible assets and concluded that no impairment was required.
Leases	Leases The Company determines if an arrangement is a lease, or contains a lease, at the inception of the arrangement. When the Company determines the arrangement is a lease, or contains a lease, at lease inception, it then determines whether the lease is an operating lease or a finance lease. Operating and finance leases with lease terms of one year or greater result in the Company recording a right-of-use (ROU) asset and lease liability on its balance sheet. ROU assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent its obligation to make lease payments arising from the lease. Operating and finance lease ROU assets and liabilities are initially recognized based on the present value of lease payments over the lease term. In determining the present value of lease payments, the Company uses the implicit interest rate if readily determinable or when the implicit interest rate is not readily determinable, the Company uses its incremental borrowing rate. The incremental borrowing rate is not a commonly quoted rate and is derived through a combination of inputs including the Company’s credit rating and the impact of full collateralization. The incremental borrowing rate is based on the Company’s collateralized borrowing capabilities over a similar term of the lease payments. The Company utilizes the consolidated group incremental borrowing rate for all leases. The operating lease ROU asset also includes any lease payments made and excludes any lease incentives. Specific lease terms used in computing the ROU assets and lease liabilities may include options to extend or terminate the lease when the Company believes it is reasonably certain that it will exercise that option. Lease expense for operating lease payments is recognized on a straight-line basis over the lease term. As allowed by the guidance, the Company has elected not to recognize ROU assets and lease liabilities that arise from short-term (12 months or less) leases for any class of underlying asset. Operating leases are included in operating lease ROU assets, other current liabilities, and long-term operating lease liabilities on the Company’s consolidated balance sheet. The Company’s finance leases at December 25, 2020 and December 27, 2019 were not significant.
Goodwill and Indefinite Lived Intangible Assets	Goodwill and Indefinite Lived Intangible Assets Goodwill and indefinite-lived intangible assets are not amortized but are reviewed for impairment annually. Intangible assets are presented at cost, net of accumulated amortization, and are amortized on either a straight-line method or on an accelerated method over their estimated future discounted cash flows. The Company reviews goodwill and purchased intangible assets with indefinite lives for impairment annually and whenever events or changes in circumstances indicate the carrying value of an asset may not be recoverable, such as when reductions in demand or significant economic slowdowns in the semiconductor industry are present. There were no impairments of the Company’s goodwill and purchased intangible assets in fiscal year 2020.
Deferred Debt Issuance Costs	Deferred Debt Issuance Costs Debt issuance costs incurred in connection with
Defined Benefit Plan	Defined Benefit Pension Plan The Company has a noncontributory defined benefit pension plan covering substantially all of the employees of one of its foreign entities upon termination of their employee services. For further discussion of the Company’s defined benefit pension plan see Note 8 of Notes to the Consolidated Financial Statements.
Revenue Recognition	Revenue Recognition Revenue is recognized when control of the promised goods or services is transferred to the Company’s customers, in an amount that reflects the consideration the Company expects to be entitled to in exchange for those goods or services. The Company performs the following five steps to determine when to recognize revenue: (1) identification of the contract(s) with customers, (2) identification of the performance obligations in the contract, (3) determination of the transaction price, (4) allocation of the transaction price to the performance obligations in the contract, and (5) recognition of revenue when, or as, a performance obligation is satisfied. Shipping and Handling Costs Shipping and handling costs are included as a component of cost of revenues.
Research and Development Costs	Research and Development Costs Research and development costs are expensed as incurred.
Stock-Based Compensation Expense	Stock-Based Compensation Expense The Company maintains stock-based compensation plans which allow for the issuance of equity-based awards to executives and certain employees. These equity-based awards include stock options, restricted stock awards and restricted stock units. The Company also maintains an employee stock purchase plan (“ESPP”) that provides for the issuance of shares to all eligible employees of the Company at a discounted price.
Government Subsidies	Government Subsidies Government subsidies are recognized where there is reasonable assurance that the subsidy will be received and all attached conditions will be complied with. When the subsidy relates to an expense item, it is recognized as income on a systematic basis over the periods that the related costs, for which it is intended to compensate, are expensed. When the subsidy relates to an asset, it is recognized as income in equal amounts over the expected useful life of the related asset. When the subsidy does not relate to specific expenses or assets, the income is accounted for in the period where there is reasonable assurance that the subsidy will be received.
Income Taxes	Income Taxes The Company utilizes the asset and liability method of accounting for income taxes, under which deferred taxes are determined based on the temporary differences between the financial statement and tax basis of assets and liabilities using tax rates expected to be in effect during the years in which the basis differences reverse. Deferred income taxes arise from temporary differences between the tax basis of assets and liabilities and their reported amounts in the financial statements, which will result in taxable or deductible amounts in the future. In evaluating our ability to realize our deferred tax assets within the jurisdiction from which they arise, we consider all available positive and negative evidence, including scheduled reversals of deferred tax liabilities, projected future taxable income, tax-planning strategies, and results of recent operations. In projecting future taxable income, we begin with historical results and incorporate assumptions about the amount of future federal, state, and foreign pretax operating income adjusted for items that do not have tax consequences. The assumptions about future taxable income require significant judgment and are consistent with the plans and estimates we are using to manage the underlying businesses. In evaluating the objective evidence that historical results provide, we consider recent cumulative income (loss). A valuation allowance is recorded when it is more likely than not that some of the deferred tax assets will not be realized. Income tax positions must meet a more likely than not recognition threshold to be recognized. The Company recognizes tax benefits from uncertain tax positions only if it is more likely than not that the tax position will be sustained on examination by the taxing authorities, based on the technical merits of the position. The tax benefits recognized in the financial statements from such positions are then measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. The Company recognizes potential accrued interest and penalties related to unrecognized tax benefits within the consolidated statements of income as income tax expense. The Company accounts for Global Intangible Low-Taxed Income (“GILTI”) as period costs when incurred.
Net Income per Share	Net Income per Share Basic net income per share is computed by dividing net income by the weighted average number of shares outstanding for the period. Diluted net income per share is calculated by dividing net income by the weighted average number of common shares outstanding and common equivalent shares from dilutive stock options and restricted stock using the treasury stock method, except when such shares are anti-dilutive. See Note 14 to the Notes to Consolidated Financial Statements.
Business Combinations	Business Combinations The Company recognizes assets acquired (including goodwill and identifiable intangible assets), liabilities assumed and noncontrolling interest at fair value on the acquisition date. Subsequent changes to the fair value of such assets acquired and liabilities assumed are recognized in earnings, after the expiration of the measurement period, a period not to exceed 12 months from the acquisition date. Acquisition-related expenses and acquisition-related restructuring costs are recognized in earnings in the period in which they are incurred.
Recently Issued Accounting Pronouncements Not Yet Adopted	Accounting Standard Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financing Reporting. Although there are several other new accounting pronouncements issued by the FASB, the Company does not believe any of these accounting pronouncements had or will have a material impact on its Consolidated Financial Statements.

Organization and Significant _3

Organization and Significant Accounting Policies (Tables)	12 Months Ended
	Dec. 25, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Customers as Percentage of Total Revenues	The Company’s most significant customers (having accounted for 10% or more of related) and their related revenues as a percentage of total revenues were as follows: Fiscal Year Ended 2020 2019 2018 Lam Research Corporation 42.9 % 41.7 % 55.1 % Applied Materials, Inc. 24.2 25.2 21.5 Total 67.1 % 66.9 % 76.6 %

Business Combinations (Tables)

Business Combinations (Tables) - Dynamic Manufacturing Solutions [Member]	12 Months Ended
	Dec. 25, 2020
Business Acquisition [Line Items]
Summary of Preliminary Fair Values of Assets Acquired and Liabilities Assumed at Date of Acquisition	The following table summarizes the recognized amounts of assets acquired and liabilities assumed at the date of acquisition: Fair Market Values (In millions) Accounts receivable $ 1.5 Inventories 8.9 Property, plant and equipment 5.4 Goodwill 12.3 Intangible assets 6.9 Other assets 0.3 Total assets acquired 35.3 Accounts payable (3.8 ) Other liabilities (0.1 ) Total liabilities assumed (3.9 ) Purchase price allocated $ 31.4
Unaudited Pro forma Consolidated Results of Operations	The following unaudited pro forma consolidated results of operations assume the DMS acquisition was completed as of the beginning of the 2019 fiscal year. Unaudited Pro Forma Information Year Ended December 27, 2019 (In millions, except per share amounts) Revenues $ 1,075.4 Net loss $ (8.0 ) Basic loss per share $ (0.20 ) Diluted loss per share $ (0.20 )

Balance Sheet Information (Tabl

Balance Sheet Information (Tables)	12 Months Ended
	Dec. 25, 2020
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Summary of Inventories	Inventories consisted of the following: December 25, December 27, (In millions) 2020 2019 Raw materials $ 102.9 $ 99.9 Work in process 64.5 57.6 Finished goods 13.0 14.9 Total $ 180.4 $ 172.4
Property, Plant and Equipment, Net	Property, plant and equipment, net, consisted of the following: Useful Life December 25, December 27, (In millions) (in years) 2020 2019 Land n/a $ 3.8 $ 4.8 Buildings 50 37.2 36.9 Leasehold improvements * 46.7 41.8 Machinery and equipment 5-10 73.8 58.1 Computer equipment and software 3-10 42.5 32.1 Furniture and fixtures 5 4.4 4.4 208.4 178.1 Accumulated depreciation (84.0 ) (56.7 ) Construction in progress 34.8 23.9 Total $ 159.2 $ 145.3

Fair Value (Tables)

Fair Value (Tables)	12 Months Ended
	Dec. 25, 2020
Fair Value Disclosures [Abstract]
Assets or Liabilities Measured at Fair Value	The following table summarizes, for assets or liabilities measured at fair value, the respective fair value and the classification by level of input within the fair value hierarchy: Fair Value Measurement at Reporting Date Using Description December 25, 2020 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In millions) Other assets: Forward contracts $ 1.1 $ — $ 1.1 $ — Other liabilities: Common stock purchase obligation $ 12.6 $ — $ — $ 12.6 Pension obligation $ 4.7 $ — $ — $ 4.7 Fair Value Measurement at Reporting Date Using Description December 27, 2019 Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) (In millions) Other liabilities: Contingent earn-out liability $ 9.5 $ — $ — $ 9.5 Common stock purchase obligation $ 6.8 $ — $ — $ 6.8 Pension obligation $ 4.4 $ — $ — $ 4.4
Summary of Qualitative Information About Level 3 Fair Value Measurements	The estimated fair value of foreign currency forward contracts is based upon quoted market prices obtained from independent pricing services for similar derivative contracts and these financial instruments are characterized as Level 2 assets in the fair value hierarchy. The estimated fair value of common stock purchase obligation is based on a combination of an income and market valuation approach. The income and market valuation approaches may incorporate Level 3 fair value measures for instances when observable inputs are not available. The more significant judgmental assumptions used to estimate the value of common stock purchase obligation include an estimated discount rate, a range of assumptions that form the basis of the expected future net cash flows (e.g., the revenue growth rates and operating margins), and a company specific beta. The significant judgmental assumptions used that incorporate market data, including the relative weighting of market observable information and the comparability of that information in the valuation models, are forward-looking and could be affected by future economic and market conditions. The estimated fair value of pension obligation is based on expected years of service and average compensation. The valuation model used to value pension obligation utilizes mortality rate, inflation, interest rate risks and changes in the life expectancy for pensioners. These assumptions are routinely made in the appraisal process by the independent actuary thus resulted in a Level 3 classification. There were no transfers from Level 1 or Level 2. Fair value adjustments were noncash, and therefore did not impact the Company’s liquidity or capital resources. Qualitative information about Level 3 fair value measurements is as follow: (Dollars in millions, except rate/multiple) December 25, 2020 Valuation Techniques Unobservable Input Rate/Multiple Common stock purchase obligation $ 12.6 Discounted cash flow Revenue Multiple 1.3 - 2.0 EBITDA Multiple 5.5 - 7.4 Discount rate 15.50% - 20.00% Pension obligation $ 4.7 Projected unit credit method Discount rate 2.10 % Rate on return 1.10 % Salary increase rate 4.00 %
Summary of Level 3 Activity	Following is a summary of the Level 3 activity: (In millions) Contingent earn-out liability Common stock purchase obligation Pension obligation As of December 27, 2019 $ 9.5 $ 6.8 $ 4.4 Fair value adjustments (DMS) 3.0 - - Fair value adjustments (QGT) - 5.8 - Benefits, payments and other adjustments (12.5 ) - 0.3 As of December 25, 2020 $ - $ 12.6 $ 4.7

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 25, 2020
Goodwill And Intangible Assets Disclosure [Abstract]
Details of Goodwill	Details of aggregate goodwill of the Company are as follows: (In millions) Products Services Total Balance at December 27, 2019 $ 97.6 $ 73.5 $ 171.1 Business combination - - - Balance at December 25, 2020 $ 97.6 $ 73.5 $ 171.1
Purchased Intangible Assets	Details of intangible assets were as follows: As of December 25, 2020 As of December 27, 2019 Gross Gross Useful Life Carrying Accumulated Carrying Carrying Accumulated Carrying (Dollars in millions) (in years) Amount Amortization Value Amount Amortization Value Customer relationships 6 - 10 $ 119.4 $ (50.6 ) $ 68.8 $ 119.4 $ (39.8 ) $ 79.6 Tradename 4 - 6* 27.0 (11.7 ) 15.3 27.0 (8.1 ) $ 18.9 Intellectual property/know-how 7 - 12 13.9 (9.8 ) 4.1 13.9 (8.4 ) $ 5.5 Recipes 20 73.2 (8.5 ) 64.7 73.2 (4.9 ) $ 68.3 Standard operating procedures 20 8.6 (1.0 ) 7.6 8.6 (0.6 ) $ 8.0 Total $ 242.1 $ (81.6 ) $ 160.5 $ 242.1 $ (61.8 ) $ 180.3 * The concluded that the asset life of UCT tradename of $9.0 million is indefinite and is therefore not amortized but is reviewed for impairment at least annually and whenever events or changes in circumstances indicate that the carrying value of an asset may not be recoverable.
Future Estimated Amortization Expense	Amortization (In millions) Expense 2021 $ 19.6 2022 19.3 2023 14.2 2024 14.0 2025 12.3 Thereafter 72.1 Total $ 151.5

Borrowing Arrangements (Tables)

Borrowing Arrangements (Tables)	12 Months Ended
	Dec. 25, 2020
Debt Disclosure [Abstract]
Schedule of Future Debt Payment Obligations	As of December 25, 2020, the Company’s future debt principal payment obligations for the respective fiscal years were as follows: Debt (In millions) (Principal only) 2021 $ 9.2 2022 9.0 2023 9.9 2024 8.8 2025 8.7 Thereafter 231.3 Total $ 276.9

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 25, 2020
Income Tax Disclosure [Abstract]
Provision for Income Taxes	The provision for income taxes consisted of the following: Year Ended December 25, December 27, December 28, (In millions) 2020 2019 2018 Current: Federal $ (0.1 ) $ 0.1 $ 2.3 State 0.9 0.1 0.7 Foreign 18.1 12.3 12.2 Total current 18.9 12.5 15.2 Deferred: Federal 0.3 (0.1 ) 0.2 State 0.5 0.7 0.1 Foreign (0.4 ) (3.1 ) (0.2 ) Total deferred 0.4 (2.5 ) 0.1 Total provision $ 19.3 $ 10.0 $ 15.3
U.S. and Foreign Components of Income before Income Taxes	Income before provision for income taxes was generated from the following geographic areas: Year Ended December 25, December 27, December 28, (In millions) 2020 2019 2018 United States $ (24.5 ) $ (49.7 ) $ (5.0 ) Foreign 124.2 52.0 57.3 Total pretax income $ 99.7 $ 2.3 $ 52.3
Effective Tax Rate Differs from U.S. Federal Statutory Tax Rate	The effective tax rate differs from the U.S. federal statutory tax rate as follows: Year Ended December 25, December 27, December 28, 2020 2019 2018 Federal income tax provision at statutory rate 21.0 % 21.0 % 21.0 % State income taxes, net of federal benefit 0.6 % (99.5 ) % 2.0 % Effect of foreign operations (8.3 ) % (85.3 ) % — % Change in valuation allowance (0.1 ) % 552.7 % (0.1 ) % Foreign income inclusions 4.6 % 34.5 % 2.1 % Adjustment for changes in tax law — % — % 3.6 % Common stock purchase obligation 1.2 % — % — % Income tax audit adjustment 1.3 % — % — % Other (1.0 ) % (7.5 ) % 0.7 % Effective Tax Rate 19.3 % 415.9 % 29.3 %
Significant Components of Deferred Tax Assets and Liabilities	Significant components of deferred tax assets and liabilities are as follows: Year Ended December 25, December 27, (In millions) 2020 2019 Deferred tax assets: Inventory valuation and basis difference $ 3.9 $ 3.4 State taxes 0.2 0.5 Stock compensation 1.7 1.7 Operating lease liabilities 10.0 9.0 Interest expense limitation 6.8 5.8 Intangibles 12.6 7.8 Net operating losses 6.4 6.4 Tax credits 2.6 2.2 Other timing differences 4.9 4.5 49.1 41.3 Valuation allowance (25.6 ) (25.8 ) Total deferred tax assets 23.5 15.5 Deferred tax liabilities: Undistributed earnings (0.5 ) (0.5 ) Operating lease right-of-use assets (8.5 ) (7.2 ) Depreciation (5.0 ) (3.3 ) Intangibles (6.7 ) (5.8 ) Goodwill (12.9 ) (8.4 ) Total deferred tax liabilities (33.6 ) (25.2 ) Net deferred tax liabilities $ (10.1 ) $ (9.7 )
Activity Related to Company's Unrecognized Tax Benefits	The following Balance as of December 29, 2017 $ 0.3 Increases related to current year positions 0.7 Expiration of the statute of limitations - Balance as of December 28, 2018 $ 1.0 Increases related to current year tax positions - Expiration of the statute of limitations for the assessment of taxes - Balance as of December 27, 2019 $ 1.0 Increases related to current year tax positions - Expiration of the statute of limitations for the assessment of taxes (0.1 ) Balance as of December 25, 2020 $ 0.9

Employee Stock Plans (Tables)

Employee Stock Plans (Tables)	12 Months Ended
	Dec. 25, 2020
Postemployment Benefits [Abstract]
Stock-Based Compensation Expense Included in Condensed Consolidated Statements of Operations	Total stock-based compensation during the fiscal years 2020, 2019 and 2018, respectively, in various expense categories was as follows: Year Ended December 25, December 27, December 28, (In millions) 2020 2019 2018 Cost of revenues (1) $ 1.8 $ 2.4 $ 2.1 Research and development 0.1 0.3 0.1 Sales and marketing 1.3 1.3 1.0 General and administrative 9.5 8.1 7.1 12.7 12.1 10.3 Income tax benefit (2.5 ) — (3.0 ) Net stock-based compensation expense $ 10.2 $ 12.1 $ 7.3 (1) Stock-based compensation expenses capitalized in inventory for fiscal years 2020, 2019 and 2018 were considered immaterial.
Summary of Restricted Stock Unit and Restricted Stock Award Activity	The following table summarizes the Company’s PSUs, RSUs and RSAs activities through the year ended December 25, 2020 Aggregate Intrinsic Number of Value Shares (in millions) Unvested restricted stock units and restricted stock awards at December 28, 2018 1.8 $ 14.6 Granted 1.1 Vested (0.9 ) Forfeited (0.2 ) Unvested restricted stock units and restricted stock awards at December 27, 2019 1.8 $ 41.9 Granted 0.9 Vested (0.8 ) Forfeited (0.2 ) Unvested restricted stock units and restricted stock awards at December 25, 2020 1.7 $ 54.1 Vested and expected to vest restricted stock units and restricted stock awards 1.7 $ 54.1

Revenue Recognition (Tables)

Revenue Recognition (Tables)	12 Months Ended
	Dec. 25, 2020
Revenue From Contract With Customer [Abstract]
Revenue by Geographic Area	The following table sets forth revenue by geographic area (in millions): Year Ended December 25, December 27, December 28, 2020 2019 2018 United States $ 613.7 $ 546.2 $ 602.2 Singapore 494.4 302.1 315.3 Korea 83.7 68.2 45.6 Austria 57.4 47.7 58.1 Taiwan 68.1 44.4 22.6 China 47.7 35.3 42.1 Others 33.6 22.3 10.6 Total $ 1,398.6 $ 1,066.2 $ 1,096.5

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 25, 2020
Leases [Abstract]
Summary of Components of Lease Expense	The components of lease expense were summarized as follows: Year Ended (Dollars in millions) December 25, 2020 December 27, 2019 Operating lease cost $ 13.1 $ 13.8 Short-term lease cost 1.3 1.1 Sublease income (0.1 ) (0.2 ) Total lease cost $ 14.3 $ 14.7 Operating cash flows from operating leases $ 16.9 $ 17.3 Weighted-average remaining lease term – operating leases 2.3 2.4 Weighted-average discount rate – operating leases 5.5 % 7.0 %
Summary of Future Minimum Payments under Operating Leases	Future minimum payments under operating leases as of December 25, 2020 were summarized as follows: (In millions) Operating Leases 2021 $ 12.8 2022 10.7 2023 7.7 2024 5.4 2025 4.0 Thereafter 8.5 Total minimum lease payments 49.1 Less: imputed interest 6.3 Lease liability $ 42.8 The Company entered into two new lease agreements in fiscal year 2020 with commencement dates in fiscal year 2021. The total minimum lease payments for these two new lease agreements is $22.1 million.

Net Income Per Share (Tables)

Net Income Per Share (Tables)	12 Months Ended
	Dec. 25, 2020
Earnings Per Share [Abstract]
Basic and Diluted Net Income (loss) Per Share	The following is a reconciliation of the numerators and denominators used in computing basic and diluted net income (loss) per share: Year Ended December 25, December 27, December 28, (In millions, except share amounts) 2020 2019 2018 Numerator: Net income (loss) attributable to UCT $ 77.6 $ (9.4 ) $ 36.6 Denominator: Shares used in computation — basic: Weighted average common shares outstanding 40.2 39.5 38.4 Shares used in computation — diluted: Weighted average common shares outstanding 40.2 39.5 38.4 Dilutive effect of common shares outstanding subject to repurchase 0.9 0.0 0.5 Shares used in computing diluted net income (loss) per share 41.1 39.5 38.9 Net income (loss) per share attributable to UCT — basic $ 1.93 $ (0.24 ) $ 0.95 Net income (loss) per share attributable to UCT — diluted $ 1.89 $ (0.24 ) $ 0.94

Reportable Segments (Tables)

Reportable Segments (Tables)	12 Months Ended
	Dec. 25, 2020
Segment Reporting [Abstract]
Summary of Segment Description and Data	The following table describes each segment: Segment Product or Services Markets Served Geographic Areas Products Assembly Weldments Machining Fabrication Semiconductor United States Asia Europe Services Cleaning Analytics Semiconductor United States Asia Europe Fiscal Year End December 25, December 27, December 28, (In millions) 2020 2019 2018 Revenues: Products $ 1,131.2 $ 840.8 $ 1,015.5 Services 267.4 225.4 81 Total segment revenues $ 1,398.6 $ 1,066.2 $ 1,096.5 Gross profit: Products $ 196.5 $ 121.8 $ 150.3 Services $ 95.3 $ 75.0 $ 25.5 Total segment gross profit $ 291.8 $ 196.8 $ 175.8 Operating profit: Products $ 97.2 $ 18.3 $ 52.3 Services 24.2 11.6 8.4 Total segment operating profit $ 121.4 $ 29.9 $ 60.7 December 25, December 27, (In millions) 2020 2019 Assets Products $ 868.4 $ 828.0 Services 234.1 191.3 Total segment assets $ 1,102.5 $ 1,019.3

Unaudited Quarterly Financial_2

Unaudited Quarterly Financial Results (Tables)	12 Months Ended
	Dec. 25, 2020
Quarterly Financial Information Disclosure [Abstract]
Statement of Operations Data on Quarterly Basis	The following table sets forth statement of operations data for the periods indicated. The information for each of these periods is unaudited and has been prepared on the same basis as our audited Consolidated Financial Statements included herein and includes all adjustments, consisting only of normal recurring adjustments that we consider necessary for a fair presentation of our unaudited operations data for the periods presented. Historical results are not necessarily indicative of the results to be expected in the future: First Second Third Fourth Fiscal (In million, except per share data) Quarter Quarter Quarter Quarter Year (1) 2020 Revenues $ 320.9 $ 344.8 $ 363.3 $ 369.6 $ 1,398.6 Gross profit $ 65.7 $ 73.9 $ 74.6 $ 77.6 $ 291.8 Net income $ 9.4 $ 21.3 $ 24.4 $ 22.5 $ 77.6 Earnings per share — basic $ 0.24 $ 0.53 $ 0.60 $ 0.56 $ 1.93 Earnings per share — diluted $ 0.23 $ 0.52 $ 0.59 $ 0.55 $ 1.89 2019 Revenues $ 260.1 $ 265.4 $ 254.3 $ 286.4 $ 1,066.2 Gross profit $ 44.8 $ 48.2 $ 47.5 $ 56.3 $ 196.8 Net income (loss) $ 0.6 $ (0.2 ) $ 0.50 $ (10.3 ) $ (9.4 ) Earnings (loss) per share — basic $ 0.02 $ (0.01 ) $ 0.01 $ (0.17 ) $ (0.24 ) Earnings (loss) per share — diluted $ 0.02 $ (0.01 ) $ 0.01 $ (0.17 ) $ (0.24 ) (1) Earnings per share is calculated independently each quarter and for the full year based upon their respective weighted average shares outstanding. Therefore, the sum of the quarterly earnings per share may not equal the annual earnings per share reported.

Organization and Significant _4

Organization and Significant Accounting Policies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)SegmentCustomer	Dec. 27, 2019USD ($)SegmentCustomer	Dec. 28, 2018USD ($)
Concentration Risk [Line Items]
Number of operating segments	2	2
Number of reportable segments	2
Impairments of goodwill and intangible assets | $	$ 0	$ 0	$ 0
Customer Concentration Risk [Member] | Lam Research Corporation, Applied Materials, Inc. and ASM International, Inc. [Member]
Concentration Risk [Line Items]
Number of customers with accounts receivable greater than 10% | Customer	3	3
Customer Concentration Risk [Member] | Lam Research Corporation, Applied Materials, Inc. and ASM International, Inc. [Member] | Accounts Receivable [Member]
Concentration Risk [Line Items]
Concentration percentage	62.90%	66.70%
Cinos Co., Ltd [Member]
Concentration Risk [Line Items]
Noncontrolling interest, ownership percentage by parent	86.00%
Cinos Xian Clean Technology, Ltd [Member]
Concentration Risk [Line Items]
Noncontrolling interest, ownership percentage by parent	60.00%
Minimum [Member]
Concentration Risk [Line Items]
Fiscal year duration	364 days
Useful lives range	3 years
Minimum [Member] | Internal Use Software [Member]
Concentration Risk [Line Items]
Useful lives range	3 years
Maximum [Member]
Concentration Risk [Line Items]
Fiscal year duration	371 days
Useful lives range	50 years
Measurement period to determine fair value of assets and liabilities	12 months
Maximum [Member] | Internal Use Software [Member]
Concentration Risk [Line Items]
Useful lives range	10 years

Organization and Significant _5

Organization and Significant Accounting Policies - Customers as Percentage of Total Revenues (Detail) - Sales [Member] - Customer Concentration Risk [Member]	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Concentration Risk [Line Items]
Total	67.10%	66.90%	76.60%
Lam Research Corporation [Member]
Concentration Risk [Line Items]
Total	42.90%	41.70%	55.10%
Applied Materials, Inc. [Member]
Concentration Risk [Line Items]
Total	24.20%	25.20%	21.50%

Business Combinations - Additio

Business Combinations - Additional Information (Detail) - USD ($) $ in Millions	Apr. 15, 2019	Aug. 31, 2020	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Business Acquisition [Line Items]
Revenues			$ 1,398.6	$ 1,066.2	$ 1,096.5
Operating Income			121.4	29.9	60.7
Amortization of intangible assets			19.8	20.1	$ 9.6
Dynamic Manufacturing Solutions [Member]
Business Acquisition [Line Items]
Date of acquisition	Apr. 15, 2019
Business acquisition potential cash earn-out payments	$ 12.5
Business acquisition fair value of potential earn-out payments	1.5
Total purchase consideration	31.4
Cash payment for acquisition	$ 29.9
Earn-out payments, fair market value		$ 12.5
Increase in liability recorded as other expense			$ 3	8
Revenues				35.2
Operating Income				4.9
Amortization of intangible assets				0.8
Acquisition related costs				1.2
contingent earn-out expense				$ 8
Dynamic Manufacturing Solutions [Member] | Customer Relationships [Member]
Business Acquisition [Line Items]
Total intangible assets, useful life	6 years

Business Combinations - Summary

Business Combinations - Summary of Preliminary Fair Values of Assets Acquired and Liabilities Assumed at Date of Acquisition (Detail) - USD ($) $ in Millions	Apr. 15, 2019	Dec. 25, 2020	Dec. 27, 2019
Business Acquisition [Line Items]
Goodwill		$ 171.1	$ 171.1
Dynamic Manufacturing Solutions [Member]
Business Acquisition [Line Items]
Accounts receivable	$ 1.5
Inventories	8.9
Property, plant and equipment	5.4
Goodwill	12.3
Intangible assets	6.9
Other assets	0.3
Total assets acquired	35.3
Accounts payable	(3.8)
Other liabilities	(0.1)
Total liabilities assumed	(3.9)
Purchase price allocated	$ 31.4

Business Combinations - Unaudit

Business Combinations - Unaudited Pro forma Consolidated Results of Operations (Detail) - Dynamic Manufacturing Solutions [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 27, 2019USD ($)$ / shares
Business Acquisition [Line Items]
Revenues | $	$ 1,075.4
Net loss | $	$ (8)
Basic loss per share | $ / shares	$ (0.20)
Diluted loss per share | $ / shares	$ (0.20)

Balance Sheet Information - Sum

Balance Sheet Information - Summary of Inventories (Detail) - USD ($) $ in Millions	Dec. 25, 2020	Dec. 27, 2019
Inventory Disclosure [Abstract]
Raw materials	$ 102.9	$ 99.9
Work in process	64.5	57.6
Finished goods	13	14.9
Total	$ 180.4	$ 172.4

Balance Sheet Information - Add

Balance Sheet Information - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Inventory Disclosure [Abstract]
Inventories	$ 180.4	$ 172.4
Net of reserves	12	12
Inventory write-downs	$ 3.4	2.5	$ 3.3
Restructuring charge		$ 12.6

Balance Sheet Information - Pro

Balance Sheet Information - Property, Plant and Equipment, Net (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements net excluding construction in progress	$ 208.4	$ 178.1
Accumulated depreciation	(84)	(56.7)
Construction in progress	34.8	23.9
Total	$ 159.2	145.3
Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	50 years
Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Land [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 3.8	4.8
Buildings [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 37.2	36.9
Property, plant and equipment, useful life	50 years
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 46.7	41.8
Machinery and Equipment [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 73.8	58.1
Machinery and Equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Machinery and Equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	5 years
Computer Equipment and Software [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 42.5	32.1
Computer Equipment and Software [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	10 years
Computer Equipment and Software [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	3 years
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Equipment and leasehold improvements, gross	$ 4.4	$ 4.4
Property, plant and equipment, useful life	5 years

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value, Assets and Liabilities Measured (Details) - USD ($) $ in Millions	Dec. 25, 2020	Dec. 27, 2019
Contingent Earn-out Liability [Member]
Other liabilities:
Liabilities measured at fair value		$ 9.5
Forward Contracts [Member]
Other assets:
Assets measured at fair value	$ 1.1
Common Stock Purchase Obligation [Member]
Other liabilities:
Liabilities measured at fair value	12.6	6.8
Pension Obligation [Member]
Other liabilities:
Liabilities measured at fair value	4.7	4.4
Significant Other Observable Inputs (Level 2) [Member] | Forward Contracts [Member]
Other assets:
Assets measured at fair value	1.1
Significant Unobservable Inputs (Level 3) [Member] | Contingent Earn-out Liability [Member]
Other liabilities:
Liabilities measured at fair value		9.5
Significant Unobservable Inputs (Level 3) [Member] | Common Stock Purchase Obligation [Member]
Other liabilities:
Liabilities measured at fair value	12.6	6.8
Significant Unobservable Inputs (Level 3) [Member] | Pension Obligation [Member]
Other liabilities:
Liabilities measured at fair value	$ 4.7	$ 4.4

Fair Value Measurements - Summa

Fair Value Measurements - Summary of Qualitative Information About Level 3 Fair Value Measurements (Details) $ in Millions	Dec. 25, 2020USD ($)	Dec. 27, 2019USD ($)	Dec. 28, 2018USD ($)
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration		$ 1.4	$ 4.2
Significant Unobservable Inputs (Level 3) [Member] | EBITDA Multiple [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.055
Significant Unobservable Inputs (Level 3) [Member] | EBITDA Multiple [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.074
Significant Unobservable Inputs (Level 3) [Member] | Discount Rate [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.1550
Significant Unobservable Inputs (Level 3) [Member] | Discount Rate [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.2000
Significant Unobservable Inputs (Level 3) [Member] | Rate on Return [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.0110
Significant Unobservable Inputs (Level 3) [Member] | Salary Increase Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.0400
Significant Unobservable Inputs (Level 3) [Member] | Common Stock Purchase Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 12.6
Business Combination Contingent Consideration Liability Valuation Technique Extensible List	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Significant Unobservable Inputs (Level 3) [Member] | Common Stock Purchase Obligation [Member] | Revenue Multiple [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.013
Significant Unobservable Inputs (Level 3) [Member] | Common Stock Purchase Obligation [Member] | Revenue Multiple [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.020
Significant Unobservable Inputs (Level 3) [Member] | Pension Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Contingent consideration	$ 4.7
Significant Unobservable Inputs (Level 3) [Member] | Pension Obligation [Member]
Defined Benefit Plan Disclosure [Line Items]
Business Combination Contingent Consideration Liability Valuation Technique Extensible List	uctt:ValuationTechniqueProjectedUnitsCreditMethodMember
Significant Unobservable Inputs (Level 3) [Member] | Pension Obligation [Member] | Discount Rate [Member]
Defined Benefit Plan Disclosure [Line Items]
Range	0.0210

Fair Value - Summary of the Lev

Fair Value - Summary of the Level 3 Activity - (Details) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)
Pension Obligation [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning balance	$ 4.4
Ending balance	4.7
Pension Obligation [Member] | SSB [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Benefits and other adjustments	0.3
Common Stock Purchase Obligation [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning balance	6.8
Ending balance	12.6
Common Stock Purchase Obligation [Member] | Quantum Global Technologies, LLC [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value adjustments	5.8
Contingent Earn-out Liability [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Beginning balance	9.5
Contingent Earn-out Liability [Member] | Dynamic Manufacturing Solutions [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value adjustments	3
Contingent Earn-out Liability [Member] | SSB [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Benefits and other adjustments	$ (12.5)

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets - Details of Goodwill (Detail) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)
Goodwill [Line Items]
Goodwill	$ 171.1
Business combination	0
Goodwill	171.1
Products [Member]
Goodwill [Line Items]
Goodwill	97.6
Business combination	0
Goodwill	97.6
Services [Member]
Goodwill [Line Items]
Goodwill	73.5
Business combination	0
Goodwill	$ 73.5

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets - Purchased Intangible Assets (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, accumulated amortization	$ (81.6)	$ (61.8)
Definite lives intangible assets, net carrying amount	151.5
Intangible Assets, gross carrying value	242.1	242.1
Intangible Assets, net carrying value	160.5	180.3
Customer Relationships [Member]
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, gross carrying amount	119.4	119.4
Definite lives intangible assets, accumulated amortization	(50.6)	(39.8)
Definite lives intangible assets, net carrying amount	$ 68.8	79.6
Customer Relationships [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	6 years
Customer Relationships [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	10 years
Trade Name [Member]
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, gross carrying amount	$ 27	27
Definite lives intangible assets, accumulated amortization	(11.7)	(8.1)
Definite lives intangible assets, net carrying amount	$ 15.3	18.9
Trade Name [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	4 years
Trade Name [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	6 years
Intellectual Properties/Know-How [Member]
Finite Lived Intangible Assets [Line Items]
Definite lives intangible assets, gross carrying amount	$ 13.9	13.9
Definite lives intangible assets, accumulated amortization	(9.8)	(8.4)
Definite lives intangible assets, net carrying amount	$ 4.1	5.5
Intellectual Properties/Know-How [Member] | Minimum [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	7 years
Intellectual Properties/Know-How [Member] | Maximum [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	12 years
Recipes [Member]
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	20 years
Definite lives intangible assets, gross carrying amount	$ 73.2	73.2
Definite lives intangible assets, accumulated amortization	(8.5)	(4.9)
Definite lives intangible assets, net carrying amount	$ 64.7	68.3
StandardOperatingProceduresMember
Finite Lived Intangible Assets [Line Items]
Total intangible assets, useful life	20 years
Definite lives intangible assets, gross carrying amount	$ 8.6	8.6
Definite lives intangible assets, accumulated amortization	(1)	(0.6)
Definite lives intangible assets, net carrying amount	$ 7.6	$ 8

Goodwill and Intangible Asset_4

Goodwill and Intangible Assets - Purchased Intangible Assets (Parenthetical) (Detail) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)
UCT Tradename [Member]
Finite Lived Intangible Assets [Line Items]
Indefinite lived intangible assets acquired	$ 9

Goodwill and Intangible Asset_5

Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Amortization of purchased intangible assets	$ 19.8	$ 20.1	$ 9.6

Goodwill and Intangible Asset_6

Goodwill and Intangible Assets - Future Estimated Amortization Expense (Detail) $ in Millions	Dec. 25, 2020USD ($)
Finite Lived Intangible Assets Future Amortization Expense [Abstract]
2021	$ 19.6
2022	19.3
2023	14.2
2024	14
2025	12.3
Thereafter	72.1
Definite lives intangible assets, net carrying amount	$ 151.5

Borrowing Arrangements - Additi

Borrowing Arrangements - Additional Information (Detail) € in Millions, ₩ in Billions	1 Months Ended	12 Months Ended
	Aug. 31, 2018USD ($)	Dec. 25, 2020USD ($)	Dec. 25, 2020KRW (₩)	Dec. 25, 2020EUR (€)
Debt Instrument [Line Items]
Outstanding amount of borrowing classified as long-term debt		$ 276,900,000
Bank Debt [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs		7,900,000
Outstanding amount of borrowing classified as long-term debt		269,000,000
Bank Debt [Member] | China [Member] | Cincos Xian Clean Technology, Ltd [Member]
Debt Instrument [Line Items]
Outstanding amounts		$ 1,900,000
Minimum [Member]
Debt Instrument [Line Items]
Fixed charge coverage ratio	1.25%
Minimum [Member] | Bank Debt [Member] | China [Member] | Cincos Xian Clean Technology, Ltd [Member]
Debt Instrument [Line Items]
Debt instrument interest rate		2.10%	2.10%	2.10%
Maximum [Member]
Debt Instrument [Line Items]
Consolidated leverage ratio	3.75%
Maximum [Member] | Bank Debt [Member] | China [Member] | Cincos Xian Clean Technology, Ltd [Member]
Debt Instrument [Line Items]
Debt instrument interest rate		4.10%	4.10%	4.10%
Term Loan Credit Facility [Member] | Barclays Bank PLC [Member]
Debt Instrument [Line Items]
Cash borrowed for acquisition and refinancing	$ 350,000,000
Term loan, maturity date	Aug. 27, 2025
Percentage of original outstanding principal balance as quarterly principal payment	0.625%
Debt instrument, frequency of periodic payment		The Term Loan has a maturity date of August 27, 2025, with monthly interest payments in arrears, quarterly principal payments of 0.625% of the original outstanding principal balance payable beginning in January 2019, with the remaining principal paid upon maturity.
Description of interest rate term		The Term Loan accrues interest at a rate equal to a base LIBOR rate determined by reference to the London interbank offered rate for dollars, plus 4.5% (subject to certain adjustments quarterly based upon the Company’s consolidated leverage ratio)
Outstanding term loan		$ 275,000,000
Unamortized debt issuance costs		$ 7,900,000
Term Loan Credit Facility [Member] | Barclays Bank PLC [Member] | London Interbank Offered Rate (LIBOR) [Member]
Debt Instrument [Line Items]
Debt instrument variable interest rate	4.50%
Term Loan [Member]
Debt Instrument [Line Items]
Interest rate on outstanding loan		4.65%	4.65%	4.65%
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Outstanding amount under credit facility		$ 0
Revolving Credit Facility [Member] | China [Member] | Cincos Xian Clean Technology, Ltd [Member]
Debt Instrument [Line Items]
Initial available commitment		$ 3,500,000
Maturity date		Sep. 23, 2022
Revolving Credit Facility [Member] | Korea [Member] | Cinos Co., Ltd [Member]
Debt Instrument [Line Items]
Initial available commitment		$ 1,400,000	₩ 1.6
Revolving Credit Facility [Member] | Bank Debt [Member] | Czech Republic [Member]
Debt Instrument [Line Items]
Remaining available commitments		1,000,000
Revolving Credit Facility [Member] | Bank Debt [Member] | China [Member]
Debt Instrument [Line Items]
Remaining available commitments		1,500,000
Revolving Credit Facility [Member] | Bank Debt [Member] | United States [Member]
Debt Instrument [Line Items]
Remaining available commitments		55,000,000
Revolving Credit Facility [Member] | Bank Debt [Member] | FDS [Member] | Czech Republic [Member]
Debt Instrument [Line Items]
Initial available commitment | €				€ 6
Outstanding amount under credit facility		0
Outstanding amounts		$ 0
Revolving Credit Facility [Member] | Minimum [Member] | China [Member] | Cincos Xian Clean Technology, Ltd [Member]
Debt Instrument [Line Items]
Interest rate		1.90%
Revolving Credit Facility [Member] | Minimum [Member] | Korea [Member] | Cinos Co., Ltd [Member]
Debt Instrument [Line Items]
Interest rate		1.40%
Revolving Credit Facility [Member] | Maximum [Member] | China [Member] | Cincos Xian Clean Technology, Ltd [Member]
Debt Instrument [Line Items]
Interest rate		4.10%
Revolving Credit Facility [Member] | Maximum [Member] | Korea [Member] | Cinos Co., Ltd [Member]
Debt Instrument [Line Items]
Interest rate		5.40%
Revolving Credit Facility [Member] | Barclays Bank PLC [Member]
Debt Instrument [Line Items]
Initial available commitment	$ 65,000,000
Maturity date	Aug. 27, 2023
Commitment fee percentage	0.25%
Remaining available commitments		$ 65,000,000
Letter of Credit Facility [Member] | Barclays Bank PLC [Member]
Debt Instrument [Line Items]
Initial available commitment	$ 50,000,000
Maturity date	Aug. 27, 2023
Commitment fee percentage	2.50%
Percentage of undrawn and unexpired amount of letter of credit as fronting fee	0.125%
Outstanding amount under credit facility		2,400,000
Remaining available commitments		$ 47,600,000

Borrowing Arrangements - Schedu

Borrowing Arrangements - Schedule of Future Debt Payment Obligations (Detail) $ in Millions	Dec. 25, 2020USD ($)
Debt Disclosure [Abstract]
2021	$ 9.2
2022	9
2023	9.9
2024	8.8
2025	8.7
Thereafter	231.3
Total	$ 276.9

Income Taxes - Provision for In

Income Taxes - Provision for Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Current:
Federal	$ (0.1)	$ 0.1	$ 2.3
State	0.9	0.1	0.7
Foreign	18.1	12.3	12.2
Total current	18.9	12.5	15.2
Deferred:
Federal	0.3	(0.1)	0.2
State	0.5	0.7	0.1
Foreign	(0.4)	(3.1)	(0.2)
Total deferred	0.4	(2.5)	0.1
Total provision	$ 19.3	$ 10	$ 15.3

Income Taxes - U.S. and Foreign

Income Taxes - U.S. and Foreign Components of Income before Income Taxes (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Income Tax Disclosure [Abstract]
United States	$ (24.5)	$ (49.7)	$ (5)
Foreign	124.2	52	57.3
Income before provision for income taxes	$ 99.7	$ 2.3	$ 52.3

Income Taxes - Effective Tax Ra

Income Taxes - Effective Tax Rate Differs from U.S. Federal Statutory Tax Rate (Detail)	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Income Tax Disclosure [Abstract]
Federal income tax provision at statutory rate	21.00%	21.00%	21.00%
State income taxes, net of federal benefit	0.60%	(99.50%)	2.00%
Effect of foreign operations	(8.30%)	(85.30%)
Change in valuation allowance	(0.10%)	552.70%	(0.10%)
Foreign income inclusions	4.60%	34.50%	2.10%
Adjustment for changes in tax law			3.60%
Common stock purchase obligation	1.20%
Income tax audit adjustment	1.30%
Other	(1.00%)	(7.50%)	0.70%
Effective Tax Rate	19.30%	415.90%	29.30%

Income Taxes - Components of Ne

Income Taxes - Components of Net Deferred Tax Assets and Deferred Tax Liabilities (Detail) - USD ($) $ in Millions	Dec. 25, 2020	Dec. 27, 2019
Net non-current deferred tax asset:
Total deferred tax assets	$ 23.5	$ 15.5
Non-current deferred tax liability:
Undistributed earnings	(0.5)	(0.5)
Operating lease right-of-use assets	(8.5)	(7.2)
Depreciation	(5)	(3.3)
Intangibles	(6.7)	(5.8)
Goodwill	(12.9)	(8.4)
Total deferred tax liabilities	(33.6)	(25.2)
Net deferred tax liabilities	(10.1)	(9.7)
Deferred Tax Assets Noncurrent [Member]
Net non-current deferred tax asset:
Inventory valuation and basis difference	3.9	3.4
State taxes	0.2	0.5
Stock compensation	1.7	1.7
Operating lease liabilities	10	9
Interest expense limitation	6.8	5.8
Intangibles	12.6	7.8
Net operating losses	6.4	6.4
Tax credits	2.6	2.2
Other timing differences	4.9	4.5
Deferred tax assets, gross non-current	49.1	41.3
Valuation allowance	$ (25.6)	$ (25.8)

Income Taxes - Additional Infor

Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018	Dec. 29, 2017
Income Taxes [Line Items]
Undistributed earnings of foreign subsidiaries	$ 267.2
Gross liability for unrecognized tax benefits	0.9	$ 1	$ 1	$ 0.3
Interest related to uncertain tax positions	0.3	$ 0.3	$ 0.1
Cinos Korea [Member]
Income Taxes [Line Items]
Income tax settlement by local authorities	$ 1.3
Singapore [Member] | Maximum [Member]
Income Taxes [Line Items]
Reduction in local tax on certain Singapore income from a statutory rate	17.00%
Singapore [Member] | Minimum [Member]
Income Taxes [Line Items]
Reduction in local tax on certain Singapore income from a statutory rate	5.00%
CARES ACT [Member]
Income Taxes [Line Items]
Percentage removal of taxable income limitation on net operating losses deduction	80.00%
Taxable years for carryback of NOLs	5 years
Caps for limitation on the deduction for interest expense	50.00%
Percentage of corporate charitable deduction limit of taxable income	25.00%
Eligible for cost recovery years	15 years
Percentage of bonus depreciation	100.00%
California [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 35.8
Operating loss carryforwards, expiration beginning year	2031

Income Taxes - Activity Related

Income Taxes - Activity Related to Company's Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 28, 2018
Income Tax Disclosure [Abstract]
Balance as of the beginning of period	$ 1	$ 0.3
Increases related to current year positions		0.7
Expiration of the statute of limitations for the assessment of taxes	(0.1)
Balance as of the end of period	$ 0.9	$ 1

Retirement Plans - Additional I

Retirement Plans - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Compensation And Retirement Disclosure [Abstract]
Benefit obligations	$ 9.7
Fair value of benefit plan assets	6.7
Unfunded balance of benefit plan	3
Amounts recognized in accumulated other comprehensive income	0.5	$ 1.7
Contributions to the plan by the Company and its subsidiaries	2.8
Benefits expected to be paid from pension plan in 2021	0.9
Benefits expected to be paid from pension plan in 2022	1
Benefits expected to be paid from pension plan in 2023	2.3
Benefits expected to be paid from pension plan in 2024	1
Benefits expected to be paid from pension plan in 2025	1
Aggregate benefits expected to be paid in five years from 2026-2031	$ 5.9
Contribution from salary	25.00%
Matching contribution of participation salary	50.00%
Matching contribution based upon eligibility	6.00%
Discretionary employer contributions	$ 2.4	$ 2.3	$ 1.2

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) $ in Millions	Dec. 25, 2020USD ($)
Inventories [Member]
Long Term Purchase Commitment [Line Items]
Purchase commitments	$ 205.9

Stockholders' Equity and Nonc_2

Stockholders' Equity and Noncontrolling Interests - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Aug. 27, 2018
Cinos Co., Ltd [Member]
Business Acquisition [Line Items]
Percentage of outstanding shares purchased		35.00%
Quantum Global Technologies, LLC [Member]
Business Acquisition [Line Items]
Stock purchase obligation, fair value	$ 12.6
Purchase obligation maturity period	2022-12
Cinos Korea and Cinos China [Member]
Business Acquisition [Line Items]
Percentage of value used for fair value of non-controlling interest estimates		100.00%
Quantum Global Technologies, LLC [Member] | Cinos Co., Ltd [Member]
Business Acquisition [Line Items]
Percentage of outstanding shares purchased		51.00%
Noncontrolling interest, ownership percentage by parent		86.00%
Quantum Global Technologies, LLC [Member] | Cinos Xian Clean Technology, Ltd [Member]
Business Acquisition [Line Items]
Percentage of outstanding shares purchased		35.00%
Cinos China [Member]
Business Acquisition [Line Items]
Percentage of non-controlling interest		40.00%
Cinos China [Member] | Cinos Co., Ltd [Member]
Business Acquisition [Line Items]
Noncontrolling interest, ownership percentage by parent		60.00%
Cinos Co., Ltd [Member]
Business Acquisition [Line Items]
Noncontrolling interest, ownership percentage by parent	86.00%
Percentage of non-controlling interest		14.00%

Employee Stock Plans - Addition

Employee Stock Plans - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	Dec. 25, 2020	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation		$ 12.7	$ 12.1	$ 10.3
Unrecognized compensation cost	$ 16.4	$ 16.4
Shares were subject to forfeiture	2,500,000	2,500,000
Estimated period of options amortization	1 year 7 months 6 days
2003 Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Stock-based compensation		$ 12.7	12.1	10.3
Employee Stock Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Employee common stock fair market value rate		95.00%
Number of shares of common stock issued under the ESPP		29,143,000,000
Employee Stock Purchase Plan [Member] | Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average fair value, granted		$ 19.07
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period, years		4 years
Stock Option [Member] | 2003 Amended and restated Stock Incentive Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period, years		4 years
Stock-based compensation		$ 0	$ 0	$ 0
Options terms		10 years
Stock options outstanding	0	0
Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period, years		3 years
Restricted Stock Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares vesting period, years		1 year
Restricted Stock Unit and Restricted Stock Award [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares were subject to forfeiture	1,665,987,000,000	1,665,987,000,000
Granted stock units		900,000	1,100,000
Restricted Stock Unit and Restricted Stock Award [Member] | Board Members [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted stock units		46,363,000,000	69,783,000,000	38,010,000,000
Unamortized expense of Company's unvested restricted stock awards				$ 0.4
Restricted Stock Unit and Restricted Stock Award [Member] | Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Estimated period of options amortization		1 year 7 months 6 days
Granted stock units		694,066,000,000
Unamortized expense of Company's unvested restricted stock awards	$ 16	$ 16
Unit purchase price of Restricted Stock Units		$ 0
Performance Based Vesting Restricted Stock [Member] | Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Granted stock units		148,816,000,000
Weighted average fair value, granted		$ 15.27

Employee Stock Plans - Stock-Ba

Employee Stock Plans - Stock-Based Compensation Expense Included in Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation		$ 12.7	$ 12.1	$ 10.3
Income tax benefit		(2.5)		(3)
Net stock-based compensation expense		10.2	12.1	7.3
Cost of Revenues [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation	[1]	1.8	2.4	2.1
Sales and Marketing [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation		1.3	1.3	1
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation		0.1	0.3	0.1
General and Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Stock-based compensation		$ 9.5	$ 8.1	$ 7.1
[1]	Stock-based compensation expenses capitalized in inventory for fiscal years 2020, 2019 and 2018 were considered immaterial.

Employee Stock Plans - Summary

Employee Stock Plans - Summary of Restricted Stock Unit and Restricted Stock Award Activity (Detail) - Restricted Stock Unit and Restricted Stock Award [Member] - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Unvested restricted stock units and restricted stock awards, Number of Shares, Beginning balance	1,800,000	1,800,000
Granted, Number of Shares	900,000	1,100,000
Vested, Number of Shares	(800,000)	(900,000)
Forfeited, Number of Shares	(200,000)	(200,000)
Unvested restricted stock units and restricted stock awards, Number of Shares, Ending balance	1,700,000	1,800,000	1,800,000
Vested and expected to vest restricted stock units and restricted stock awards	1,700,000
Unvested restricted stock units and restricted stock awards, Beginning balance, Aggregate Intrinsic Value	$ 54.1	$ 41.9	$ 14.6
Vested and expected to vest restricted stock units and restricted stock awards, Aggregate Intrinsic Value	$ 54.1

Revenue Recognition - Additiona

Revenue Recognition - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)
Accounts Receivable [Member]
Concentration Risk [Line Items]
Unpaid customer rebates	$ 3.4
Maximum [Member]
Concentration Risk [Line Items]
Product warranty period (in years)	2 years

Revenue Recognition - Summary o

Revenue Recognition - Summary of Revenue by Geographic Area (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	$ 1,398.6	$ 1,066.2	$ 1,096.5
United States [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	613.7	546.2	602.2
Singapore [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	494.4	302.1	315.3
Korea [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	83.7	68.2	45.6
Austria [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	57.4	47.7	58.1
Taiwan [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	68.1	44.4	22.6
China [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	47.7	35.3	42.1
Others [Member]
Revenues From External Customers And Long Lived Assets [Line Items]
Revenues	$ 33.6	$ 22.3	$ 10.6

Leases - Summary of Components

Leases - Summary of Components of Lease Expense (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019
Leases [Abstract]
Operating lease cost	$ 13.1	$ 13.8
Short-term lease cost	1.3	1.1
Sublease income	(0.1)	(0.2)
Total lease cost	14.3	14.7
Operating cash flows from operating leases	$ 16.9	$ 17.3
Weighted-average remaining lease term – operating leases	2 years 3 months 18 days	2 years 4 months 24 days
Weighted-average discount rate – operating leases	5.50%	7.00%

Leases - Summary of Future Mini

Leases - Summary of Future Minimum Payments under Operating Leases (Detail) $ in Millions	Dec. 25, 2020USD ($)
Leases [Abstract]
2021	$ 12.8
2022	10.7
2023	7.7
2024	5.4
2025	4
Thereafter	8.5
Total minimum lease payments	49.1
Less: imputed interest	6.3
Lease liability	$ 42.8

Leases - Additional Information

Leases - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)
Lessee Lease Description [Line Items]
Total minimum lease payments	$ 49.1
Two New Lease Arrangement [Member]
Lessee Lease Description [Line Items]
Lease commencement year	2021
Total minimum lease payments	$ 22.1

Net Income Per Share - Basic an

Net Income Per Share - Basic and Diluted Net Income (loss) Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 25, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 27, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Numerator:
Net income (loss) attributable to UCT	$ 22,500	$ 24,400	$ 21,300	$ 9,400	$ (10,300)	$ 500	$ (200)	$ 600	$ 77,600	$ (9,400)	$ 36,600
Shares used in computation — basic:
Weighted average common shares outstanding									40.2	39.5	38.4
Shares used in computation — diluted:
Weighted average common shares outstanding									40.2	39.5	38.4
Dilutive effect of common shares outstanding subject to repurchase									0.9	0	0.5
Shares used in computing diluted net income (loss) per share									41.1	39.5	38.9
Net income (loss) per share attributable to UCT — basic									$ 1.93	$ (0.24)	$ 0.95
Net income (loss) per share attributable to UCT — diluted									$ 1.89	$ (0.24)	$ 0.94

Reportable Segments - Additiona

Reportable Segments - Additional Information (Detail) - Segment	12 Months Ended
	Dec. 25, 2020	Dec. 27, 2019
Segment Reporting [Abstract]
Number of operating segments	2	2

Reportable Segments - Summary o

Reportable Segments - Summary of Segment Description (Detail)	12 Months Ended
	Dec. 25, 2020
Products [Member]
Segment Reporting Information [Line Items]
Product or Services	Assembly Weldments Machining Fabrication
Markets Served	Semiconductor
Geographic Areas	United States Asia Europe
Services [Member]
Segment Reporting Information [Line Items]
Product or Services	Cleaning Analytics
Markets Served	Semiconductor
Geographic Areas	United States Asia Europe

Reportable Segments - Summary_2

Reportable Segments - Summary of Segment Data (Detail) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 25, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 27, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Revenues:
Revenues									$ 1,398.6	$ 1,066.2	$ 1,096.5
Total segment revenues									1,398.6	1,066.2	1,096.5
Gross profit:
Total segment gross profit	$ 77.6	$ 74.6	$ 73.9	$ 65.7	$ 56.3	$ 47.5	$ 48.2	$ 44.8	291.8	196.8	175.8
Operating profit:
Products									121.4	29.9	60.7
ASSETS
Total segment assets	1,102.5				1,019.3				1,102.5	1,019.3
Products [Member]
Revenues:
Revenues									1,131.2	840.8	1,015.5
Total segment revenues									1,131.2	840.8	1,015.5
Gross profit:
Total segment gross profit									196.5	121.8	150.3
Operating profit:
Products									97.2	18.3	52.3
ASSETS
Total segment assets	868.4				828				868.4	828
SSB [Member]
Revenues:
Revenues									267.4	225.4	81
Total segment revenues									267.4	225.4	81
Gross profit:
Total segment gross profit									95.3	75	25.5
Operating profit:
Products									24.2	11.6	$ 8.4
ASSETS
Total segment assets	$ 234.1				$ 191.3				$ 234.1	$ 191.3

Government Subsidies - Addition

Government Subsidies - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 25, 2020USD ($)
Government Grants And Subsidies [Abstract]
Government subsidies to employees	$ 3.1
Other income	1.5
Offset to cost of goods sold and other operating expenses	$ 1.6

Statement of Operations Data on

Statement of Operations Data on Quarterly Basis (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 25, 2020	Sep. 25, 2020	Jun. 26, 2020	Mar. 27, 2020	Dec. 27, 2019	Sep. 27, 2019	Jun. 28, 2019	Mar. 29, 2019	Dec. 25, 2020	Dec. 27, 2019	Dec. 28, 2018
Quarterly Financial Information Disclosure [Abstract]
Revenues	$ 369,600	$ 363,300	$ 344,800	$ 320,900	$ 286,400	$ 254,300	$ 265,400	$ 260,100	$ 1,398,600	$ 1,066,200	$ 1,096,500
Total segment gross profit	77,600	74,600	73,900	65,700	56,300	47,500	48,200	44,800	291,800	196,800	175,800
Net income (loss) attributable to UCT	$ 22,500	$ 24,400	$ 21,300	$ 9,400	$ (10,300)	$ 500	$ (200)	$ 600	$ 77,600	$ (9,400)	$ 36,600
Earnings (loss) per share — basic	$ 0.56	$ 0.60	$ 0.53	$ 0.24	$ (0.17)	$ 0.01	$ (0.01)	$ 0.02	$ 1.93	$ (0.24)
Earnings (loss) per share — diluted	$ 0.55	$ 0.59	$ 0.52	$ 0.23	$ (0.17)	$ 0.01	$ (0.01)	$ 0.02	$ 1.89	$ (0.24)