0000866291-21-000046 | 10-Q | XBRL Viewer

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Cover Page - shares	6 Months Ended
Cover Page - shares	Sep. 24, 2021	Oct. 20, 2021
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 24, 2021
Document Transition Report	false
Entity File Number	001-39675
Entity Registrant Name	ALLEGRO MICROSYSTEMS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	46-2405937
Entity Address, Address Line One	955 Perimeter Road
Entity Address, City or Town	Manchester,
Entity Address, State or Province	NH
Entity Address, Postal Zip Code	03103
City Area Code	603
Local Phone Number	626-2300
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	ALGM
Security Exchange Name	NASDAQ
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		189,702,550
Entity Central Index Key	0000866291
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--03-25

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Current assets:
Cash and cash equivalents	$ 248,579	$ 197,214
Restricted cash	7,105	6,661
Trade accounts receivable, net of provision for expected credit losses of $176 at September 24, 2021 and allowance for doubtful accounts of $138 at March 26, 2021	73,971	69,500
Trade and other accounts receivable due from related party	23,853	23,832
Accounts receivable – other	1,295	1,516
Inventories	78,042	87,498
Prepaid expenses and other current assets	13,069	18,374
Assets held for sale	0	25,969
Total current assets	445,914	430,564
Property, plant and equipment, net	198,069	192,393
Operating lease right-of-use assets	17,054	0
Deferred income tax assets	20,134	26,972
Goodwill	20,093	20,106
Intangible assets, net	36,131	36,366
Equity investment in related party	27,169	26,664
Other assets, net	38,687	14,613
Total assets	803,251	747,678
Current liabilities:
Trade accounts payable	29,158	35,389
Amounts due to related party	3,686	2,353
Accrued expenses and other current liabilities	52,049	78,932
Current portion of operating lease liabilities	3,523	0
Total current liabilities	88,416	116,674
Obligations due under Senior Secured Credit Facilities	25,000	25,000
Operating lease liabilities, less current portion	13,793	0
Other long-term liabilities	19,489	19,133
Total liabilities	146,698	160,807
Commitments and contingencies (Note 16)
Stockholders' Equity:
Preferred Stock, $0.01 par value; 20,000,000 shares authorized, no shares issued or outstanding at September 24, 2021 and March 26, 2021	0	0
Common stock, $0.01 par value; 1,000,000,000 shares authorized, 189,702,550 shares issued and outstanding at September 24, 2021; 1,000,000,000 shares authorized, 189,588,161 issued and outstanding at March 26, 2021	1,897	1,896
Additional paid-in capital	604,488	592,170
Retained earnings	64,406	3,551
Accumulated other comprehensive loss	(15,368)	(11,865)
Equity attributable to Allegro MicroSystems, Inc.	655,423	585,752
Non-controlling interests	1,130	1,119
Total stockholders’ equity	656,553	586,871
Total liabilities, non-controlling interest and stockholders' equity	$ 803,251	$ 747,678

CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Statement of Financial Position [Abstract]
Allowances for doubtful accounts	$ 176	$ 138
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	20,000,000	20,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	1,000,000,000	1,000,000,000
Common stock, shares issued (in shares)	189,702,550	189,588,161
Common stock, shares outstanding (in shares)	189,702,550	189,588,161

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Net sales	$ 193,610	$ 136,649	$ 381,752	$ 251,650
Cost of goods sold	91,078	74,879	185,060	134,179
Gross profit	102,532	61,770	196,692	117,471
Operating expenses:
Research and development	29,590	25,130	59,144	49,510
Selling, general and administrative	34,088	24,238	66,152	51,027
Change in fair value of contingent consideration	300	0	600	0
Total operating expenses	63,978	49,368	125,896	100,537
Operating income	38,554	12,402	70,796	16,934
Other (expense) income:
Interest (expense) income, net	(1,150)	350	(1,495)	663
Foreign currency transaction gain (loss)	202	(1,318)	(52)	(1,186)
Income in earnings of equity investment	226	246	505	458
Other, net	1,534	20	1,582	213
Income before income tax provision	39,366	11,700	71,336	17,082
Income tax provision	6,143	2,082	10,406	2,610
Net income	33,223	9,618	60,930	14,472
Net income attributable to non-controlling interests	37	34	75	68
Net income attributable to Allegro MicroSystems, Inc.	$ 33,186	$ 9,584	$ 60,855	$ 14,404
Net income attributable to Allegro MicroSystems, Inc. per share (Note 17):
Basic (in dollars per share)	$ 0.17	$ 0.96	$ 0.32	$ 1.44
Diluted (in dollars per share)	$ 0.17	$ 0.96	$ 0.32	$ 1.44
Weighted average shares outstanding:
Basic (in shares)	189,673,788	10,000,000	189,629,535	10,000,000
Diluted (in shares)	191,676,422	10,000,000	191,416,250	10,000,000
Non-Related Party Revenue
Net sales	$ 156,445	$ 114,138	$ 309,134	$ 205,519
Related Party Revenue
Net sales	$ 37,165	$ 22,511	$ 72,618	$ 46,131

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 33,223	$ 9,618	$ 60,930	$ 14,472
Net income attributable to non-controlling interests	37	34	75	68
Net income attributable to Allegro MicroSystems, Inc.	33,186	9,584	60,855	14,404
Other comprehensive (loss) income:
Foreign currency translation adjustment	(3,537)	1,900	(3,567)	6,180
Net actuarial loss amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax	0	0	0	(313)
Comprehensive income	29,649	11,484	57,288	20,271
Other comprehensive loss (income) attributable to non-controlling interest	34	(31)	64	(24)
Comprehensive income attributable to Allegro MicroSystems, Inc.	$ 29,683	$ 11,453	$ 57,352	$ 20,247

CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non-Controlling Interests	Common Class A Common Stock	Common Class L Common Stock
Beginning balance (in shares) at Mar. 27, 2020							10,000,000	622,470
Beginning balance at Mar. 27, 2020	$ 634,132		$ 458,697	$ 194,355	$ (19,976)	$ 950	$ 100	$ 6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	14,472			14,404		68
Issuance of Class L shares, net of forfeitures (in shares)								15,828
Capitalization changes related to organizational structure of affiliates and direct and indirect interests in subsidiaries	(19,692)		(19,692)
Reclassification of certain class L shares	(298)		(298)
Stock-based compensation	1,025		1,025
Foreign currency translation adjustment	6,180				6,156	24
Net actuarial loss amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax	313				313
Ending balance (in shares) at Sep. 25, 2020							10,000,000	638,298
Ending balance at Sep. 25, 2020	635,506		439,732	208,759	(14,133)	1,042	$ 100	$ 6
Beginning balance (in shares) at Jun. 26, 2020							10,000,000	638,298
Beginning balance at Jun. 26, 2020	623,935		439,679	199,175	(16,002)	977	$ 100	$ 6
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	9,618			9,584		34
Capitalization changes related to organizational structure of affiliates and direct and indirect interests in subsidiaries	(527)		(527)
Stock-based compensation	580		580
Foreign currency translation adjustment	1,900				1,869	31
Net actuarial loss amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax	0
Ending balance (in shares) at Sep. 25, 2020							10,000,000	638,298
Ending balance at Sep. 25, 2020	$ 635,506		439,732	208,759	(14,133)	1,042	$ 100	$ 6
Beginning balance (in shares) at Mar. 26, 2021	189,588,161	189,588,161
Beginning balance at Mar. 26, 2021	$ 586,871	$ 1,896	592,170	3,551	(11,865)	1,119
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	60,930			60,855		75
Employee stock purchase plan issuances (in shares)		59,563
Employee stock purchase plan issuances	1,291		1,291
Stock-based compensation, net of forfeitures (in shares)		54,826
Stock-based compensation, net of forfeitures	11,028	$ 1	11,027
Foreign currency translation adjustment	(3,567)				(3,503)	(64)
Net actuarial loss amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax	$ 0
Ending balance (in shares) at Sep. 24, 2021	189,702,550	189,702,550
Ending balance at Sep. 24, 2021	$ 656,553	$ 1,897	604,488	64,406	(15,368)	1,130
Beginning balance (in shares) at Jun. 25, 2021		189,581,621
Beginning balance at Jun. 25, 2021	619,379	$ 1,896	597,001	31,220	(11,865)	1,127
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	33,223			33,186		37
Employee stock purchase plan issuances (in shares)		59,563
Employee stock purchase plan issuances	1,291		1,291
Stock-based compensation, net of forfeitures (in shares)		61,366
Stock-based compensation, net of forfeitures	6,197	$ 1	6,196
Foreign currency translation adjustment	(3,537)				(3,503)	(34)
Net actuarial loss amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax	$ 0
Ending balance (in shares) at Sep. 24, 2021	189,702,550	189,702,550
Ending balance at Sep. 24, 2021	$ 656,553	$ 1,897	$ 604,488	$ 64,406	$ (15,368)	$ 1,130

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 60,930	$ 14,472
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	24,511	24,026
Amortization of deferred financing costs	25	0
Deferred income taxes	(2,246)	1,307
Stock-based compensation	11,027	1,025
(Gain) loss on disposal of assets	(330)	293
Loss on contingent consideration change in fair value	600	0
Provisions for inventory and credit losses/bad debt	2,869	209
Unrealized gains on marketable securities	(978)	0
Changes in operating assets and liabilities:
Trade accounts receivable	(2,299)	6,196
Accounts receivable - other	181	(1,292)
Inventories	4,415	(8,772)
Prepaid expenses and other assets	(6,761)	(16,725)
Trade accounts payable	(6,188)	2,793
Due to/from related parties	1,312	10,731
Accrued expenses and other current and long-term liabilities	(17,192)	(5,623)
Net cash provided by operating activities	69,876	28,640
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of property, plant and equipment	(33,821)	(18,091)
Acquisition of business, net of cash acquired	(12,549)	(8,500)
Proceeds from sales of property, plant and equipment	27,407	282
Investments in marketable securities	(4,334)	0
Contribution of cash balances due to divestiture of subsidiary	0	(16,335)
Net cash used in investing activities	(23,297)	(42,644)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock under employee stock purchase plan	1,291	0
Net cash provided by financing activities	1,291	0
Effect of exchange rate changes on Cash and cash equivalents and Restricted cash	3,939	2,480
Net increase in Cash and cash equivalents and Restricted cash	51,809	(11,524)
Cash and cash equivalents and Restricted cash at beginning of period	203,875	219,876
CASH AND CASH EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD:	255,684	208,352
RECONCILIATION OF CASH AND CASH EQUIVALENTS AND RESTRICTED CASH:
Cash and cash equivalents	248,579	201,998
Restricted cash	7,105	6,354
Cash and cash equivalents and Restricted cash	255,684	208,352
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid for interest	269	107
Cash paid for income taxes	7,993	6,385
Noncash transactions:
Changes in Trade accounts payable related to Property, plant and equipment, net	(3,183)	(4,000)
Loans to cover purchase of common stock under employee stock plan	0	171
Recognition of right of use assets and lease liability upon adoption of new accounting standard	$ 356	$ 0

Nature of the Business and Basis of Presentation	6 Months Ended
Nature of the Business and Basis of Presentation	Sep. 24, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of the Business and Basis of Presentation	Nature of the Business and Basis of Presentation Allegro MicroSystems, Inc., together with its consolidated subsidiaries (“AMI” or the “Company”), is a global leader in designing, developing and manufacturing sensing and power solutions for motion control and energy-efficient systems in automotive and industrial markets. The Company is headquartered in Manchester, New Hampshire, and has a global footprint with 16 locations across four continents. The accompanying unaudited condensed consolidated financial statements have been prepared by the Company. Certain information and footnote disclosures normally included in financial statements prepared in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been condensed or omitted pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”). The unaudited condensed consolidated financial statements include the Company’s accounts and those of its subsidiaries. All intercompany balances have been eliminated in consolidation. These unaudited condensed consolidated financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K filed with the SEC on May 19, 2021 (the “2021 Annual Report”). In the opinion of the Company’s management, the financial information for the interim periods presented reflects all adjustments necessary for a fair presentation of the Company's financial position, results of operations and cash. The results reported in these unaudited condensed consolidated financial statements are not necessarily indicative of results that may be expected for the entire year. On November 2, 2020, the Company completed its initial public offering (“IPO”). Refer to Note 1, “Nature of Business and Basis of Presentation” to the Company’s 2021 Annual Report for details. Financial Periods The Company’s second quarter three-month period is a 13-week period ending on the Friday closest to the last day in September. The Company’s second quarter of fiscal 2022 ended September 24, 2021, and the Company’s second quarter of fiscal 2021 ended September 25, 2020.

Summary of Significant Accounting Policies	6 Months Ended
Summary of Significant Accounting Policies	Sep. 24, 2021
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and disclosures of contingencies at the date of the unaudited consolidated financial statements and the reported amounts of net sales and expenses during the reporting period. Such estimates relate to useful lives of fixed and intangible assets, allowances for doubtful accounts and customer returns and sales allowances. Such estimates could also relate to the fair value of acquired assets and liabilities, including goodwill and intangible assets, net realizable value of inventory, accrued liabilities, the valuation of stock-based awards, deferred tax valuation allowances, and other reserves. On an ongoing basis, management evaluates its estimates. Actual results could differ from those estimates, and such differences may be material to the unaudited condensed consolidated financial statements. Reclassifications Certain reclassifications have been made to prior-period amounts to conform to current-period reporting classifications. Concentrations of Credit Risk and Significant Customers Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents and accounts receivable. The Company maintains its cash and cash equivalents with financial institutions that management believes to be of a high credit quality. To manage credit risk related to accounts receivables, the Company evaluates the creditworthiness of its customers and maintains allowances, to the extent necessary, for potential credit losses based upon the aging of its accounts receivable balances and known collection issues. The Company has not experienced any significant credit losses to date. As of September 24, 2021 and March 26, 2021, Sanken Electric Co., Ltd. (“Sanken”) accounted for 24.3% and 22.7% of the Company’s outstanding trade accounts receivable, net, respectively, including related party trade accounts receivable. No other customers accounted for 10% or more of outstanding trade accounts receivable, net during those periods. For the three- and six-month periods ended September 24, 2021, Sanken accounted for 19.2% and 19.0% of total net sales, respectively. No other customers accounted for 10% or more of total net sales for either of the three- and six-month periods ended September 24, 2021. For the three- and six-month periods ended September 25, 2020, Sanken accounted for 16.5% and 18.3% of total net sales, respectively. No other customers accounted for 10% or more of total net sales for either of the three- and six-month periods ended September 25, 2020. During the three-month period September 24, 2021, sales from customers located outside of the United States accounted for, in the aggregate, 85.6% of the Company’s total net sales, with Greater China accounting for 26.2%, Japan accounting for 19.2% and South Korea accounting for 10.2%. During the six-month period September 24, 2021, sales from customers located outside of the United States accounted for, in the aggregate, 85.7% of the Company’s total net sales, with Greater China accounting for 24.5%, Japan accounting for 19.0% and South Korea accounting for 10.9%. No other countries accounted for greater than 10% of total net sales for the three- and six-month periods ended September 24, 2021. During the three-month period September 25, 2020, sales from customers located outside of the United States, in the aggregate, accounted for 84.7% of the Company’s total net sales, with Greater China accounting for 27.8% and Japan accounting for 16.4%. During the six-month period September 25, 2020, sales from customers located outside of the United States, in the aggregate, accounted for 86.5% of the Company’s total net sales, with Greater China accounting for 27.8%, Japan accounting for 18.3% and South Korea accounting for 10.4%. No other countries accounted for greater than 10% of total net sales for the three- and six-month periods ended September 25, 2020. Recently Adopted Accounting Standards The Company qualifies as “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected to “opt in” to the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for nonpublic companies. In February 2016, the Financial Accounting Standards Board (“FASB”) issued its new lease accounting guidance in Accounting Standards Update (“ASU”) 2016‑02, “Leases (Topic 842)” (“ASU 2016-02”), which is codified as Accounting Standard Codification (“ASC”) Topic 842 (“ASC 842”) and replaces ASC Topic 840, Leases (“ASC 840”). ASU 2016-02 and all subsequent amendments amend various aspects of existing guidance for leases and require significant additional quantitative and qualitative disclosures about lease arrangements. ASU 2016-02 requires lessees to recognize lease assets representing the right to use an underlying asset and lease liabilities representing the obligation to make lease payments over the lease term, measured on a discounted basis, for substantially all leases. ASU 2016-02 retains a distinction between finance leases and operating leases using classification criteria that are substantially similar to the previous lease guidance. Although the Company has elected to opt-in to the extended transition dates for new or revised accounting standards to align with nonpublic companies, the Company elected to early adopt ASU 2016-02 effective March 27, 2021. The Company used the optional transition method to the modified retrospective approach, which eliminates the requirement to restate the prior period financial statements. Under this transition provision, the Company has applied ASU 2016-02 to reporting periods beginning on March 27, 2021, while prior periods continue to be reported and disclosed in accordance with the legacy guidance under ASC 840. A number of practical expedients and policy elections are available under the new guidance to reduce the burden of adoption and ongoing compliance with ASC 842. The Company elected the “package of practical expedients”, which permitted the Company to retain lease classification and initial direct costs for any identified leases that existed prior to adoption of ASC 842. Under this transition guidance, the Company also did not reassess whether any existing contracts at March 27, 2021 are, or contain, leases and carried forward its initial determination under legacy lease guidance. The Company has elected not to adopt the “hindsight” practical expedient and, therefore, will measure the right-of-use (“ROU”) asset and lease liability using the remaining portion of the lease term at adoption on March 27, 2021. The Company made an accounting policy election available under the new lease standard to not recognize lease assets and lease liabilities for leases with a term of 12 months or less. For all other leases, the initial measurement of the lease liability is based on the present value of future lease payments over the lease term at the application date or the commencement date of the lease. Lease payments may include fixed rent escalation clauses or payments that depend on an index or a rate (such as the consumer price index) measured using the index or applicable rate at lease commencement. Subsequent changes in the index or rate and any other variable payments, such as market-rate base rent adjustments, are recognized as variable lease expense in the period incurred. Payments for terminating a lease are included in lease payments only when it is probable they will be incurred. To determine the present value of lease payments, the Company uses its incremental borrowing rate, as the leases generally do not have a readily determinable implicit discount rate. The Company applies judgment in assessing factors such as Company-specific credit risk, lease term, nature and quality of the underlying collateral, currency and economic environment in determining the lease-specific incremental borrowing rate. The carrying value of the ROU assets at the application date equals the lease liability adjusted for any initial direct costs incurred and lease payments made at or before the commencement date and for any lease incentives. The Company’s leases generally include a non-lease component representing additional services transferred to the Company. The Company has made an accounting policy election to account for lease and non-lease components in its contacts as a single lease component for all asset classes. The non-lease components are usually variable in nature and recorded in variable lease expense in the period incurred. Adoption of ASC 842 resulted in ROU assets of $18,403 and lease liabilities of $18,759 related to the Company’s operating leases at March 27, 2021. The Company does not have any leases classified as finance leases. The adoption of ASC 842 did not materially impact the Company’s consolidated net income or consolidated cash flows and did not result in a cumulative-effect adjustment to the opening balance of retained earnings. In June 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”), which adds an impairment model (known as the current expected credit loss (“CECL”) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce complexity by decreasing the number of credit impairment models that entities use to account for debt instruments. The Company adopted ASU 2016-13 effective March 27, 2021 and concluded that the standard update did not have a material impact on either the financial position, results of operations, cash flows, or related disclosures. There was no impact on beginning balance retained earnings upon adoption of this ASU. The Company is exposed to credit losses primarily through trade and other financing receivables arising from revenue transactions. The Company uses an aging schedule method to estimate current expected credit losses based on days of delinquency, including information about past events and current economic conditions. The Company’s accounts receivable is separated into two categories using a portfolio methodology to evaluate the allowance under the CECL impairment model based on sales categorization and similar credit quality and worthiness of the customers: original equipment manufacturers (“OEMs”) and distributors. The receivables in each category share similar risk characteristics. The change to the CECL impairment model resulted in an immaterial increase in the provision for expected credit losses compared to the allowance for doubtful accounts under the previous incurred loss method. The Company increases the allowance for expected credits losses when the Company determines all or a portion of a receivable is uncollectible. The Company recognizes recoveries as a decrease to the allowance for expected credit losses. For the three- and six-month periods ended September 24, 2021, no material changes in the allowance occurred. Recently Issued Accounting Standards Not Yet Adopted In May 2021, the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2021-04”). ASU 2021-04 outlines how an entity should account for modifications made to equity-classified written call options, including stock options and warrants to purchase the entity’s own common stock. The guidance in the ASU requires an entity to treat a modification of an equity-classified written call option that does not cause the option to become liability-classified as an exchange of the original option for a new option. This guidance applies whether the modification is structured as an amendment to the terms and conditions of the equity-classified written call option or as termination of the original option and issuance of a new option. The guidance is effective prospectively for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, including in an interim period as of the beginning of the fiscal year that includes that interim period. The Company is currently in the process of evaluating the impact of this new guidance on the consolidated financial statements and the related disclosures.

Revenue from Contract with Customers

6 Months Ended

Sep. 24, 2021

Revenue from Contract with Customer [Abstract]

Revenue from Contracts with Customers

Revenue from Contracts with Customers The Company generates revenue from the sale of magnetic sensor integrated circuits (“ICs”) and application-specific analog power semiconductors. The following tables summarize net sales disaggregated by application, by product and by geography for the three- and six-month periods ended September 24, 2021 and September 25, 2020. The categorization of net

sales by application is determined using various characteristics of the product and the application into which the Company’s product will be incorporated. The categorization of net sales by geography is determined based on the location the products are being shipped to.

Net sales by application:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020

Automotive	$	126,031	$	89,479	$	259,554	$	165,857
Industrial	36,321		21,650		66,630		42,056
Other	31,258		25,520		55,568		43,737



Total net sales	$	193,610	$	136,649	$	381,752	$	251,650

Net sales by product:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Power integrated circuits	$	65,523	$	50,271	$	132,195	$	91,870
Magnetic sensors	127,621		86,097		248,263		159,499
Photonics	466		281		1,294		281


Total net sales	$	193,610	$	136,649	$	381,752	$	251,650

Net sales by geography:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Americas:
United States	$	27,785	$	20,962	$	54,626	$	33,958
Other Americas	5,427		3,249		11,776		5,177
EMEA:
Europe	32,466		24,374		67,217		42,220
Asia:
Japan	37,165		22,511		72,618		46,131
Greater China	50,683		37,935		93,462		70,006
South Korea	19,746		12,515		41,679		26,127
Other Asia	20,338		15,103		40,374		28,031
Total net sales	$	193,610	$	136,649	$	381,752	$	251,650

The Company recognizes sales net of returns, credits issued, price protection adjustments and stock rotation rights. At September 24, 2021 and March 26, 2021, these adjustments were $17,583 and $15,412, respectively, and were netted against trade accounts receivable in the unaudited consolidated balance sheets. These amounts represent charges of $2,171 and $1,864, respectively, for the six-month periods ended September 24, 2021 and September 25, 2020, respectively.

Unsatisfied performance obligations primarily represent contracts for products with future delivery dates. The Company elected to not disclose the amount of unsatisfied performance obligations, as these contracts have original expected durations of less than one year.

- Definition

The entire disclosure of revenue from contract with customer to transfer good or service and to transfer nonfinancial asset. Includes, but is not limited to, disaggregation of revenue, credit loss recognized from contract with customer, judgment and change in judgment related to contract with customer, and asset recognized from cost incurred to obtain or fulfill contract with customer. Excludes insurance and lease contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-URI http://asc.fasb.org/topic&trid=49130388

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130551-203045

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 13
-Subparagraph (b)(2)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130556-203045

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 9
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130550-203045

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130558-203045

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130554-203045

+ Details

Fair Value Measurements

6 Months Ended

Sep. 24, 2021

Fair Value Disclosures [Abstract]

Fair Value Measurements

The following tables present information about the Company’s financial assets and liabilities as of September 24, 2021 and March 26, 2021 measured at fair value on a recurring basis and indicate the level of the fair value hierarchy utilized to determine such fair values:


	Fair Value Measurement at September 24, 2021 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market fund deposits	$	16,341	$	—	$	—	$	16,341
Restricted cash:
Money market fund deposits	7,105		—		—		7,105
Other assets, net (long-term):
Investments in marketable securities	$	5,287	$	—	$	—	$	5,287
Total assets	$	28,733	$	—	$	—	$	28,733
Liabilities:
Other long-term liabilities:
Contingent consideration	$	—	$	—	$	5,400	$	5,400
Total liabilities	$	—	$	—	$	5,400	$	5,400


	Fair Value Measurement at March 26, 2021 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market fund deposits	$	16,327	$	—	$	—	$	16,327
Restricted cash:
Money market fund deposits	6,661		—		—		6,661
Total assets	$	22,988	$	—	$	—	$	22,988
Liabilities:
Other long-term liabilities:
Contingent consideration	—		—		4,800		4,800
Total liabilities	$	—	$	—	$	4,800	$	4,800

The following table represents the unrealized gains and losses on investments in marketable securities held with a readily determinable fair value for the six-month period ended September 24, 2021:



Net gains and losses recognized during the period on equity securities	$	978
Less: Net gains and losses recognized during the period on equity securities sold during the period	—
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting date	$	978

In addition to the unrealized gains in the table above, the change in fair value of the equity securities was impacted by unrealized foreign currency exchange losses of $25 for the six-month period ended September 24, 2021

The following table shows the change in fair value of Level 3 contingent consideration in connection with the fiscal year 2021 purchase of Voxtel, Inc. (“Voxtel”), a privately-held technology company located in Beaverton, Oregon that

develops, manufactures and supplies photonic and advanced 3D imaging technologies (the “Voxtel Acquisition”), for the six-month period ended September 24, 2021:


	Level 3 Contingent Consideration
Balance at March 26, 2021	$	4,800
Change in fair value of contingent consideration	600

Balance at September 24, 2021	$	5,400

Assets and liabilities measured at fair value on a recurring basis also consist of marketable securities, unit investment trust fund, loans, bonds, stock and other investments which are the Company’s defined benefit plan assets. Fair value information for those assets and liabilities, including their classification in the fair value hierarchy, is included in Note 15, “Retirement Plans.”

During the six-month periods ended September 24, 2021 and September 25, 2020, there were no transfers among Level 1, Level 2 and Level 3 asset or liabilities.

- Definition

The entire disclosure for the fair value of financial instruments (as defined), including financial assets and financial liabilities (collectively, as defined), and the measurements of those instruments as well as disclosures related to the fair value of non-financial assets and liabilities. Such disclosures about the financial instruments, assets, and liabilities would include: (1) the fair value of the required items together with their carrying amounts (as appropriate); (2) for items for which it is not practicable to estimate fair value, disclosure would include: (a) information pertinent to estimating fair value (including, carrying amount, effective interest rate, and maturity, and (b) the reasons why it is not practicable to estimate fair value; (3) significant concentrations of credit risk including: (a) information about the activity, region, or economic characteristics identifying a concentration, (b) the maximum amount of loss the entity is exposed to based on the gross fair value of the related item, (c) policy for requiring collateral or other security and information as to accessing such collateral or security, and (d) the nature and brief description of such collateral or security; (4) quantitative information about market risks and how such risks are managed; (5) for items measured on both a recurring and nonrecurring basis information regarding the inputs used to develop the fair value measurement; and (6) for items presented in the financial statement for which fair value measurement is elected: (a) information necessary to understand the reasons for the election, (b) discussion of the effect of fair value changes on earnings, (c) a description of [similar groups] items for which the election is made and the relation thereof to the balance sheet, the aggregate carrying value of items included in the balance sheet that are not eligible for the election; (7) all other required (as defined) and desired information.

+ References + Details

Trade Accounts Receivable, net

6 Months Ended

Sep. 24, 2021

Receivables [Abstract]

Trade Accounts Receivable, net

Trade accounts receivable, net (including related party trade accounts receivable) consisted of the following:


	September 24, 2021		March 26, 2021
Trade accounts receivable	$	115,274	$	108,546
Less:
Provision for expected credit losses and allowance for doubtful accounts	(176)		(138)
Returns and sales allowances	(17,407)		(15,274)
Related party trade accounts receivable	(23,720)		(23,634)
Total	$	73,971	$	69,500

Changes in the Company’s allowance for doubtful accounts and returns and sales allowances were as follows:


Description	Allowance for Doubtful Accounts		Returns and Sales Allowances		Total
Balance at March 26, 2021	$	138	$	15,274	$	15,412
Charged to costs and expenses or revenue	38		82,365		82,403
Write-offs, net of recoveries	—		(80,232)		(80,232)
Balance at September 24, 2021	$	176	$	17,407	$	17,583


Description	Allowance for Doubtful Accounts		Returns and Sales Allowances		Total
Balance at March 27, 2020	$	288	$	17,185	$	17,473
Charged to costs and expenses or revenue	50		64,316		64,366
Write-offs, net of recoveries	—		(62,502)		(62,502)
Balance at September 25, 2020	$	338	$	18,999	$	19,337

Inventories

6 Months Ended

Sep. 24, 2021

Inventory Disclosure [Abstract]

Inventories

Inventories include material, labor and overhead and consisted of the following:


	September 24, 2021		March 26, 2021
Raw materials and supplies	$	10,265	$	9,629
Work in process	43,964		50,095
Finished goods	23,813		27,774

Total	$	78,042	$	87,498

The Company recorded inventory provisions totaling $1,852 and $5,041 for the three- and six-month periods ended September 24, 2021, respectively, and $490 and $2,073 for the three- and six-month periods ended September 25, 2020, respectively.

The Company discontinued a product line manufactured by Voxtel and subsequently recognized impairment charges, which represented much of the increase in inventory provisions, for the related inventory of $271 and $3,106 for the three- and six-month periods ended September 24, 2021, respectively.

Assets Held For Sale	6 Months Ended
Assets Held For Sale	Sep. 24, 2021
Discontinued Operations and Disposal Groups [Abstract]
Assets Held For Sale	Assets Held for SaleAs of March 26, 2021, the Company had entered into a definitive agreement to sell its Thailand-based facility (the “AMTC Facility”) as it had already transferred production to the Manila, Philippines facility, which was reclassified from Property, plant and equipment, net to Assets held for sale in fiscal year 2021. The sale of the AMTC Facility was completed on August 3, 2021 following receipt of government approvals in Thailand and the fulfillment of customary closing conditions. The Company received cash of $27,405, which with related selling costs, resulted in a gain on the final disposition of $370.

Property, Plant and Equipment, net

6 Months Ended

Sep. 24, 2021

Property, Plant and Equipment [Abstract]

Property, Plant and Equipment, net

Property, plant and equipment, net is stated at cost, and consisted of the following:


	September 24, 2021		March 26, 2021
Land	$	16,227	$	16,602
Buildings, building improvements and leasehold improvements	56,992		56,911
Machinery and equipment	520,133		491,025
Office equipment	6,268		6,281
Construction in progress	16,947		29,201
Total	616,567		600,020
Less accumulated depreciation	(418,498)		(407,627)
Total	$	198,069	$	192,393

Total depreciation expense amounted to $11,222 and $22,342 for the three- and six-month periods ended September 24, 2021, respectively, and $11,797 and $22,606 for the three- and six-month periods ended September 25, 2020, respectively.

Long-lived assets include property, plant and equipment and related deposits on such assets, and capitalized tooling costs. The geographic locations of the Company’s long-lived assets, net, based on physical location of the assets, as of September 24, 2021 and March 26, 2021 are as follows:


	September 24, 2021		March 26, 2021
United States	$	35,433	$	36,529
Philippines	155,564		148,374
Thailand	—		1,698
Other	7,407		7,190
Total	$	198,404	$	193,791

Amortization of prepaid tooling costs amounted to $33 and $66 for the three- and six-month periods ended September 24, 2021, respectively, and $19 and $36 for the three- and six-month periods ended September 25, 2020, respectively.

Goodwill and Intangible Assets

6 Months Ended

Sep. 24, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Goodwill and Intangible Assets

The table below summarizes the changes in the carrying amount of goodwill as follows:


	Total
Balance at March 26, 2021	$	20,106

Currency translation	(13)
Balance at September 24, 2021	$	20,093

Intangible assets, net is as follows:


	September 24, 2021
Description	Gross		Accumulated Amortization		Net Carrying Amount		Weighted- Average Lives
Patents	$	34,616	$	13,799	$	20,817	10 years
Customer relationships	6,951		6,668		283		9 years
Process technology	13,100		1,197		11,903		12 years
Indefinite-lived and legacy process technology	4,050		1,650		2,400
Trademarks	200		44		156		5 years
Legacy trademarks	629		57		572
Other	32		32		—
Total	$	59,578	$	23,447	$	36,131


	March 26, 2021
Description	Gross		Accumulated Amortization		Net Carrying Amount		Weighted- Average Lives
Patents	$	32,751	$	12,307	$	20,444	10 years
Customer relationships	6,193		5,865		328		9 years
Process technology	13,100		651		12,449		12 years
Indefinite-lived and legacy process technology	4,050		1,650		2,400
Trademarks	200		24		176		5 years
Legacy trademarks	627		58		569
Other	32		32		—
Total	$	56,953	$	20,587	$	36,366

Intangible assets amortization expense was $1,084 and $2,103 for the three- and six-month periods ended September 24, 2021, respectively, and $671 and $1,384 for the three- and six-month periods ended September 25, 2020,

respectively. The majority of the Company’s intangible assets are related to patents as noted above. The Company capitalizes external legal costs incurred in the defense of its patents when it believes that a significant, discernible increase in value will result from the defense and a successful outcome of the legal action is probable. When the Company capitalizes patent defense costs, it amortizes these costs over the remaining estimated useful life of the patent, which is generally 10 years. There were no significant costs capitalized during either of the first six months of fiscal years 2022 or 2021.

As of September 24, 2021, annual amortization expense of intangible assets for the next five fiscal years is expected to be as follows:


Remainder of 2022	$	2,326
2023	3,360
2024	3,241
2025	3,039
2026	2,823
Thereafter	21,342
Total	$	36,131

Other Assets, net

6 Months Ended

Sep. 24, 2021

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Other Assets, net

The composition of other assets, net is as follows:


	September 24, 2021		March 26, 2021
VAT receivables long-term, net	$	8,958	$	8,177
Income taxes receivable long-term	11,462		—
Investments in marketable securities (1)	5,287		—
Deposits	8,567		3,573
Prepaid contracts long-term	1,662		1,295
Deferred financing costs	99		149
Other	2,652		1,419
Total	$	38,687	$	14,613

(1) Represents equity investments in an entity whose equity securities have a readily determinable fair value. These strategic investments represent less than a 20% ownership interest in the entity, and the Company does not maintain power over or control of the entity. These investments are measured at fair value with unrealized gains and losses related to changes in the entity’s stock price and the impact of changes in foreign exchange rates each included in the consolidated statements of operations.

Accrued Expenses and Other Current Liabilities

6 Months Ended

Sep. 24, 2021

Payables and Accruals [Abstract]

Accrued Expenses and Other Current Liabilities

The composition of accrued expenses and other current liabilities is as follows:


	September 24, 2021		March 26, 2021

Accrued management incentives	$	16,167	$	21,538
Accrued salaries and wages	16,838		15,060
Base acquisition purchase price due	2,000		14,588
Deposits on AMTC Facility	—		14,531
Accrued vacation	6,056		5,739
Accrued severance	497		572
Accrued professional fees	3,472		2,029
Accrued income taxes	1,487		514
Accrued utilities	622		623
Other current liabilities	4,910		3,738
Total	$	52,049	$	78,932

Leases

6 Months Ended

Sep. 24, 2021

Leases [Abstract]

Leases

The Company determines if an arrangement is or contains a lease at inception, which is the date on which the terms of the contract are agreed to and the agreement creates enforceable rights and obligations. The Company also considers whether its service arrangements include the right to control the use of an asset.

The Company leases real estate, equipment and vehicles under operating lease agreements that have initial terms ranging from 1 to 11 years. The Company does not have any leases classified as finance leases. Some leases include one or more options to exercise renewal terms, generally at the Company’s sole discretion, that can extend the lease term. Certain leases contain rights to terminate whereby those termination options are held by either the Company, the lessor, or both parties. These options to extend or terminate a lease are included in the lease term only when it is reasonably certain that the Company will exercise that option. The Company’s leases generally do not contain any material restrictive covenants.

Operating lease cost is recognized on a straight-line basis over the lease term. Information regarding the Company’s leases are as follows:


	Three-Month Period Ended			Six-Month Period Ended
	September 24, 2021				September 24, 2021
Lease costs:
Operating lease expense	$	1,154			$	2,302
Short term lease expense	87				141

Other information:
Operating cash flows from operating leases	$	1,244			$	2,474
Weighted-average remaining lease term – operating leases	5.71 years				5.71 years
Weighted-average discount rate – operating leases	4.6		%		4.6		%

Rent expense incurred under operating lease agreements was $1,537 and $2,772 for the three- and six-month periods ended September 24, 2021, respectively, and $1,122 and $2,305 for the three- and six-month periods ended September 25, 2020.

As of September 24, 2021, expirations of lease obligations by fiscal year were as follows:


Remainder of 2022	$	2,137
2023	3,922
2024	3,526
2025	3,095
2026	2,623
Thereafter	4,463
Total undiscounted lease payments	$	19,766
Less: present value adjustment	(2,450)
Total operating lease liabilities	$	17,316

Information as Lessee under ASC 840

Future minimum lease payments for noncancellable operating leases as reported under the previous lease guidance as of March 26, 2021 are as follows:


2022	$	2,887
2023	2,726
2024	2,644
2025	2,172
2026	1,773
Thereafter	3,713
Total	$	15,915

Debt and Other Borrowings	6 Months Ended
Debt and Other Borrowings	Sep. 24, 2021
Debt Disclosure [Abstract]
Debt and Other Borrowings	Debt and Other Borrowings On September 30, 2020, the Company entered into a term loan credit agreement with Credit Suisse AG, Cayman Islands Branch, as administrative agent and collateral agent, and the other agents, arrangers and lenders party thereto, providing for a $325,000 senior secured term loan facility due in 2027 (the “Term Loan Facility”). On September 30, 2020, the Company also entered into a revolving facility credit agreement with Mizuho Bank, Ltd., as administrative agent and collateral agent, and the other agents, arrangers and lenders party thereto, providing for a $50,000 senior secured revolving credit facility expiring in 2023 (the “Revolving Credit Facility” and, together with the Term Loan Facility, the “Senior Secured Credit Facilities”). The Revolving Credit Facility is secured by a lien on the same collateral and on the same basis as the Term Loan Facility. Interest on the Term Loan Facility is calculated at LIBOR plus 3.75% to 4.00% based on the Company’s net leverage ratio, and LIBOR is subject to a 0.5% floor. The Company’s outstanding borrowings bore an interest rate of 4.25% at September 24, 2021. As of both September 24, 2021 and March 26, 2021, the Company had $25,000 outstanding under the Term Loan Facility and had not borrowed on the Revolving Credit Facility. Included in the Term Loan Facility were deferred financing costs of $9,374, which the Company has deducted from the carrying amount presented on its unaudited consolidated balance sheet and amortized into interest expense or recognized as loss on debt extinguishment. Included in the Revolving Credit Facility were deferred financing costs of $300, which the Company classified the related short-term and long-term portions within “Prepaid expenses and other current assets” and “Other assets” on its unaudited consolidated balance sheet and is amortizing those costs over the term of the facility. The unamortized portion of the deferred financing costs associated with the Revolving Credit Facility was $199 at September 24, 2021. On November 26, 2019, the Company, through its subsidiaries, entered into a line of credit agreement with a financial institution that provides for a maximum borrowing capacity of 60,000 Philippine pesos (approximately $1,796 at September 24, 2021) at the bank’s prevailing interest rate. While this line of credit initially expired on August 21, 2021 (in connection with certain delays as a result of the COVID-19 pandemic and its impact on bank operations), the line of credit was extended in September 2021 and is now expected to expire on August 21, 2022. There were no borrowings outstanding under this line of credit as of September 24, 2021 and March 26, 2021. On November 20, 2019, the Company, through its subsidiaries, entered into a line of credit agreement with a financial institution that provides for a maximum capacity of 75,000 Philippine pesos (approximately $2,246 at September 24, 2021) at the bank’s prevailing interest rate. While this line of credit initially expired on June 30, 2021 (in connection with certain delays as a result of the COVID-19 pandemic and its impact on bank operations), the line of credit was extended in September 2021 and is now expected to expire on June 30, 2022. There were no borrowings outstanding under this line of credit as of September 24, 2021 and March 26, 2021.

Other Long-Term Liabilities

6 Months Ended

Sep. 24, 2021

Other Liabilities Disclosure [Abstract]

Other Long-Term Liabilities

The composition of other long-term liabilities is as follows:


	September 24, 2021		March 26, 2021

Accrued management incentives	$	614	$	628
Accrued retirement	10,669		10,656
Accrued contingent consideration	5,400		4,800
Provision for uncertain tax positions (net)	2,806		2,774
Other	—		275
Total	$	19,489	$	19,133

Retirement Plans

6 Months Ended

Sep. 24, 2021

Retirement Benefits [Abstract]

Retirement Plans

The Company recognizes the funded status (i.e., the difference between the fair value of plan assets and the benefit obligations) of its defined benefit pension plans in its unaudited consolidated balance sheets with a corresponding adjustment to accumulated other comprehensive income, net of tax. These amounts will continue to be recognized as a component of future net periodic benefit costs consistent with the Company’s past practice. Further, actuarial gains and losses and prior service costs that arise in future periods and are not recognized as net periodic benefit costs in the same periods will be recognized as a component of other comprehensive income. Those amounts will also be recognized as a component of future net periodic benefit costs consistent with the Company’s past practice. The Company uses a measurement date for its defined benefit pension plans and other postretirement benefit plans that is equivalent to its fiscal year-end.

Plan Descriptions

Non-U.S. Defined Benefit Plan

The Company, through its wholly owned subsidiary, Allegro MicroSystems Philippines, Inc. (“AMPI”), has a defined benefit pension plan, which is a noncontributory plan that covers substantially all employees of the respective subsidiary. The plan’s assets are invested in common trust funds, bonds and other debt instruments and stocks.

Effect on the unaudited statements of operations

Expense related to the non-United States (“U.S.”). defined benefit plan was as follows:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Service cost	$	371	$	277	$	754	$	547
Interest cost	161		156		327		308
Expected return on plan assets	(76)		(74)		(155)		(152)


Amortization of prior service cost	—		2		—		4
Actuarial loss	52		45		105		79
Net periodic pension expense	$	508	$	406	$	1,031	$	786

Information on Plan Assets

The table below sets forth the fair value of the entity’s plan assets as of September 24, 2021 and March 26, 2021, using the same three-level hierarchy of fair value inputs described in the significant accounting policies included in the Company’s 2021 Annual Report.


	Fair Value at September 24, 2021		Level 1		Level 2		Level 3
Assets of non-U.S. defined benefit plan:
Government securities	$	1,726	$	1,726	$	—	$	—
Unit investment trust fund	1,053		—		1,053		—
Loans	620		—		—		620
Bonds	867		—		867		—
Stocks and other investments	2,438		1,340		2		1,096
Total	$	6,704	$	3,066	$	1,922	$	1,716


	Fair Value at March 26, 2021		Level 1		Level 2		Level 3
Assets of non-U.S. defined benefit plan:
Government securities	$	1,646	$	1,646	$	—	$	—
Unit investment trust fund	1,221		—		1,221		—
Loans	584		—		—		584
Bonds	1,112		—		1,112		—
Stocks and other investments	3,081		1,947		1		1,133
Total	$	7,644	$	3,593	$	2,334	$	1,717

The following table shows the change in fair value of Level 3 plan assets for the six-month period ended September 24, 2021:


	Level 3 Non-U.S. Defined Plan Assets
	Loans		Stocks
Balance at March 26, 2021	$	584	$	1,133
Additions during the year	273		—
Redemptions during the year	(214)		—
Revaluation of equity securities	(1)		—
Change in foreign currency exchange rates	(22)		(37)
Balance at September 24, 2021	$	620	$	1,096

The investments in the Company’s major benefit plans largely consist of low-cost, broad-market index funds to mitigate risks of concentration within the market sectors. In recent years, the Company’s investment policy has shifted toward a closer matching of the interest-rate sensitivity of the plan assets and liabilities. The appropriate mix of equity and bond investments is determined primarily through the use of detailed asset-liability modeling studies that look to balance the impact of changes in the discount rate against the need to provide asset growth to cover future service cost. The Company, through its wholly owned subsidiary, Allegro MicroSystems, LLC’s (“AML”), non-U.S. defined benefit plan, has added a greater proportion of fixed income securities with return characteristics that are more closely aligned with changes in liabilities caused by discount rate volatility. There are no significant restrictions on the amount or nature of the investments that may be acquired or held by the plans.

During the three- and six-month periods ended September 24, 2021, the Company contributed approximately $343 and $696 to its non-U.S. pension plan, respectively. During the three- and six-month periods ended September 25, 2020, the Company contributed approximately $247 and $487 to its non-U.S. pension plan, respectively. The Company expects to contribute approximately $943 to its non-U.S. pension plan in fiscal year 2022.

Other Defined Benefit Plans

In December 1993, the Company commenced with a rollover pension promise agreement (“Pension Promise”) to offer a then European employee an insured annuity upon their retirement at age 65. The employee was the only eligible participant of the Pension Promise. The impact associated with the expense and related other income with the Pension Promise was insignificant in fiscal years 2021 and 2020, respectively. The total values of the Pension Promise in the amounts of 797 and 928 British Pounds Sterling at September 24, 2021 and March 26, 2021, respectively (approximately $1,087 and $1,272 at September 24, 2021 and March 26, 2021, respectively), were classified with other in other assets, net and accrued retirement in other long-term liabilities in the Company’s unaudited consolidated balance sheets.

Defined Contribution Plan

The Company has a 401(k) plan that covers all employees meeting certain service and age requirements. Employees are eligible to participate in the plan upon hire when the service and age requirements are met. Employees may contribute up to 35% of their compensation, subject to the maximum contribution allowed by the Internal Revenue Service. All employees are 100% vested in their contributions at the time of plan entry.

Eligible AML U.S. employees may contribute up to 50% of their pretax compensation to a defined contribution plan, subject to certain limitations, and AML may match, at its discretion, 100% of the participants’ pretax contributions, up to a maximum of 5% of their eligible compensation. Matching contributions by AML totaled approximately $1,089 and $2,345 for the three- and six-month periods ended September 24, 2021, respectively, and approximately $1,040 and $2,069 for the three- and six-month periods ended September 25, 2020, respectively.

The Company, through its AML subsidiary, Allegro MicroSystems Europe, Ltd. (“Allegro Europe”), also has a defined contribution plan (the “AME Plan”) covering substantially all employees of Allegro Europe. Contributions to the AME Plan by the Company totaled approximately $211 and $429 for the three- and six-month periods ended September 24, 2021, respectively, and approximately $206 and $385 for the three- and six-month periods ended September 25, 2020, respectively.

- Definition

The entire disclosure for retirement benefits.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
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+ Details

Commitment and Contingencies	6 Months Ended
Commitment and Contingencies	Sep. 24, 2021
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Insurance The Company, through its subsidiaries, utilizes self-insured employee health programs for employees in the United States. The Company records estimated liabilities for its self-insured health programs based on information provided by the third-party plan administrators, historical claims experience and expected costs of claims incurred but not reported. The Company monitors its estimated liabilities on a quarterly basis. As facts change, it may become necessary to make adjustments that could be material to the Company’s unaudited consolidated financial position and results of operations. The accrued liability related to self-insurance was $660 and $1,518 as of September 24, 2021 and March 26, 2021, respectively, and was included in accrued expenses and other current liabilities in the Company’s unaudited consolidated balance sheets. Legal proceedings The Company is subject to various legal proceedings and claims, the outcomes of which are subject to significant uncertainty. The Company does not believe there are any such matters that could have a material adverse effect on the Company’s financial position, results of operations or cash flows. The Company records an accrual for legal contingencies when it is determined that it is probable that a liability has been incurred and the amount of the loss can be reasonably estimated. In making such determinations, the Company evaluates, among other things, the degree of probability of an unfavorable outcome and, when it is probable that a liability has been incurred, and the ability to make a reasonable estimate of the loss. If the occurrence of liability is probable, the Company will disclose the nature of the contingency, and if estimable, will provide the likely amount of such loss or range of loss. Indemnification From time to time, the Company has agreed to indemnify and hold harmless certain customers for potential allegations of infringement of intellectual property rights and patents arising from the use of its products. To date, the Company has not incurred any costs in connection with such indemnification arrangements; therefore, there was no accrual of such amounts at September 24, 2021 or March 26, 2021. Environmental Matters The Company establishes accrued liabilities for environmental matters when it is probable that a liability has been incurred and the amount of the liability can be reasonably estimated. If the contingency is resolved for an amount greater or less than the accrual, or the Company’s share of the contingency increases or decreases or other assumptions relevant to the development of the estimate were to change, the Company would recognize an additional expense or benefit in the unaudited consolidated statements of operations during the period such determination was made. No environmental accruals were established at September 24, 2021 or March 26, 2021.

Net Income per Share

6 Months Ended

Sep. 24, 2021

Earnings Per Share [Abstract]

Net Income per Share

In connection with completion of the Company’s IPO on November 2, 2020 and immediately following the pricing of the IPO, all outstanding shares of Class A common stock and Class L common stock were automatically converted into an aggregate of 166,500,000 shares of common stock (the “Common Stock Conversion”). Outstanding shares of Class A and Class L common stock were converted to common stock in the Common Stock Conversion at conversion rates of approximately 15.822 and 13.010 shares of common stock to each share of Class A and Class L common stock, respectively. As part of the Common Stock Conversion, 2,066,508 and 1,766 shares of common stock were returned to the Company for tax payments made on behalf of holders of Class A common stock and Class L common stock, respectively, in withhold to cover tax transactions.

Prior to the Company’s IPO, shares of Class A common stock were entitled to a priority dividend of 8%. After Class A shareholders received an annualized return on capital of 8%, distributions of the remaining value were split between Class A and Class L shareholders based on the achievement of certain return targets. In determining income to the Class A stockholders for computing basic and diluted earnings per share for the three- and six-month periods ended September 25, 2020, the Company did not allocate income to the shares of Class L common stock in accordance with ASC 260, because such classes of shares would not have shared in the distribution had all of the income for the periods been distributed. Accordingly, earnings per share calculations were provided only for the Class A shares with a weighted average of 10,000,000 shares for the three- and six-month periods ended September 25, 2020.

The following table sets forth the basic and diluted net income attributable to Allegro MicroSystems, Inc. per share. The number of shares of common stock reflected in the calculation is the total shares of common stock (vested and unvested) held on the IPO date, after the Common Stock Conversion.


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Net income attributable to Allegro MicroSystems, Inc.	$	33,186	$	9,584	$	60,855	$	14,404
Net income attributable to common stockholders	33,223		9,618		60,930		14,472
Basic weighted average shares of common stock	189,673,788		10,000,000		189,629,535		10,000,000
Dilutive effect of common stock equivalents	2,002,634		—		1,786,715		—
Diluted weighted average shares of common stock	191,676,422		10,000,000		191,416,250		10,000,000
Basic net income attributable to Allegro MicroSystems, Inc. per share	$	0.17	$	0.96	$	0.32	$	1.44
Basic net income attributable to common stockholders per share	$	0.18	$	0.96	$	0.32	$	1.45
Diluted net income attributable to Allegro MicroSystems, Inc. per share	$	0.17	$	0.96	$	0.32	$	1.44
Diluted net income attributable to common stockholders per share	$	0.17	$	0.96	$	0.32	$	1.45

The computed net income per share for the three- and six-month periods ended September 24, 2021 and September 25, 2020 does not assume conversion of securities that would have an antidilutive effect on income per share. There were 1,567 and 6,012 contingently issuable shares under the employee stock purchase plan excluded for the three- and six-month periods ended September 24, 2021 as such securities would have an antidilutive effect on income per share. There were no such convertible securities to consider for the three- and six-month periods ended September 25, 2020.

The following table represents issuable weighted average share information for the respective periods:


	Three-Month Period Ended		Six-Month Period Ended
	September 24, 2021	September 25, 2020	September 24, 2021	September 25, 2020
Restricted stock units	1,026,069	—	922,968	—
Performance stock units	976,565	—	863,747	—


Total	2,002,634	—	1,786,715	—

Common Stock and Stock-Based Compensation

6 Months Ended

Sep. 24, 2021

Share-based Payment Arrangement [Abstract]

Common Stock and Stock-Based Compensation

The Company accounts for stock-based compensation through the measurement and recognition of compensation expense for share-based payment awards made to employees over the related requisite service period, including stock options, performance share units (“PSUs”), restricted share units (“RSUs”) and restricted shares (all part of our equity incentive plan).

During the six-month period ended September 24, 2021, the Company granted 960,031 RSUs to employees with an estimated grant date fair value of $24.96. Stock-based compensation expense related to non-vested awards not yet recorded at September 24, 2021 was $29,231, which is expected to be recognized over a weighted-average of 1.57 years. During the six-month period ended September 24, 2021, 64,583 shares vested.

PSUs are included at 100% - 200% of target goals. The intrinsic value of the PSU’s that were unvested during the six-month period ended September 24, 2021 was $38,211. The total compensation cost related to unvested awards not yet recorded at September 24, 2021 was $16,865, which is expected to be recognized over a weighted average of 2.03 years. No shares vested during the six-month period ended September 24, 2021.

During the six-month period ended September 24, 2021, 59,201 shares of the Company’s restricted common stock vested. In addition, 9,757 shares were forfeited, which reduced common stock outstanding during the same period. The Company had 337,369 unvested shares of restricted common stock at September 24, 2021 with a weighted average grant date fair value of $14.00 and remaining vesting period of 1.33 years.

The Company recorded stock-based compensation expense in the following expense categories of its unaudited consolidated statements of operations:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Cost of sales	$	722	$	53	$	1,250	$	150
Research and development	1,043		32		1,795		53
Selling, general and administrative	4,431		495		7,982		822
Total stock-based compensation	$	6,196	$	580	$	11,027	$	1,025

Income Taxes

6 Months Ended

Sep. 24, 2021

Income Tax Disclosure [Abstract]

Income Taxes

The Company recorded the following tax (benefit) provision in its unaudited consolidated statements of operations:


	Three-Month Period Ended						Six-Month Period Ended
	September 24, 2021			September 25, 2020			September 24, 2021			September 25, 2020
Operating taxes	$	6,150		$	1,589		$	11,268		$	2,405
Discrete tax items	(7)			493			(862)			205
Provision for income taxes	$	6,143		$	2,082		$	10,406		$	2,610
Annual operating tax rate	15.6		%	13.6		%	15.8		%	14.1		%
Effective tax rate	15.6		%	17.8		%	14.6		%	15.3		%

The Company’s provision for income taxes is comprised of the year-to-date taxes based on an estimate of the annual effective tax rate plus the tax impact of discrete items.

The Company is subject to tax in the U.S. and various foreign jurisdictions. The Company’s effective tax rate can fluctuate primarily based on: the mix of its U.S. and foreign income; the impact of discrete transactions; and the difference between the amount of tax benefit generated by the foreign derived intangible income deduction (“FDII”) and research credits offset by the additional tax from the global intangible low-tax income (“GILTI”).

The Company regularly assesses the likelihood of outcomes that could result from the examination of its tax returns by the IRS and other tax authorities to determine the adequacy of its income tax reserves and expense. Should actual events or results differ from the Company’s then-current expectations, charges or credits to the Company’s provision for income taxes may become necessary. Any such adjustments could have a significant effect on the results of operations.

Income tax expense and the effective income tax rate were $6,143, or 15.6%, and $10,406, or 14.6%, for the three- and six-month periods ended September 24, 2021, respectively, and $2,082, or 17.8%, and $2,610, or 15.3%, for the three- and six-month periods ended September 25, 2020, respectively. The fluctuation in our effective income tax rate relates primarily to differences in our US taxable income, estimated FDII benefits, GILTI income, research credits, non-deductible stock-based compensation charges, and discrete tax items.

- Definition

The entire disclosure for income taxes. Disclosures may include net deferred tax liability or asset recognized in an enterprise's statement of financial position, net change during the year in the total valuation allowance, approximate tax effect of each type of temporary difference and carryforward that gives rise to a significant portion of deferred tax liabilities and deferred tax assets, utilization of a tax carryback, and tax uncertainties information.

+ References + Details

Related Party Transactions	6 Months Ended
Related Party Transactions	Sep. 24, 2021
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Transactions involving Sanken The Company sells products and services to, and purchases in-process products from, Sanken. In addition, prior to March 28, 2020, the Company also sold products for Sanken. Net sales of the Company’s products and services to Sanken totaled $37,165 and $72,618 during the three- and six-month periods ended September 24, 2021, respectively, and $22,511 and $46,131 during the three- and six-month periods ended September 25, 2020, respectively. Trade accounts receivables, net of allowances from Sanken, totaled $23,720 and $21,595 as of September 24, 2021 and March 26, 2021, respectively. Other accounts receivable from Sanken totaled $133 and $198 as of September 24, 2021 and March 26, 2021, respectively. Transactions involving PSL In May 2009, the Company entered into a technology development agreement (the “IC Technology Development Agreement”) with Polar Semiconductor, Inc. (“PSI”) (subsequently changed to Polar Semiconductor, LLC (“PSL”)), and Sanken, pursuant to which the parties agreed upon the general terms under which they may, from time to time, undertake certain activities (the “IC Process Development Activities”) to develop new technologies to be used by PSI to manufacture products for the Company and Sanken, as well as the ownership and use of such technologies following their development. The IC Technology Development Agreement provides that the expenses for all IC Process Development Activities will be shared equally by the Company and Sanken on an annual basis (subject to any exceptions upon which the parties may agree from time to time), with such expenses being paid to PSL by Sanken in the form of an up-front annual fee, with PSL being responsible for any expenses that exceed the amount of such fee. The IC Technology Development Agreement will continue in effect until such time as the Company, PSL and Sanken mutually agree to its termination or adopt a successor agreement, or in the event that the companies fail to agree upon the annual fee for that fiscal year within three months after the commencement of such fiscal year. During both of the three- and six-month periods ended September 24, 2021 and September 25, 2020, the Company (through PSL) received no fees from Sanken pursuant to the IC Technology Development Agreement, and, during the same periods, the Company paid no fees to PSL pursuant to the IC Technology Development Agreement. There are also no expected payments to be made during the remainder of fiscal year 2022. In April 2015, PSL and Sanken entered into a discrete technology development agreement (as amended, the “Discrete Technology Development Agreement”), pursuant to which the parties agreed upon the general terms under which they, from time to time, would undertake certain activities (the “Discrete Development Activities”) to develop new technologies to be used by PSL to manufacture products for Sanken, as well as the ownership and use of such technologies following their development. In June 2018, the Company, PSL and Sanken entered into an amendment to the Discrete Technology Development Agreement pursuant to which the parties agreed to the assignment of all rights and obligations of PSL under such agreement to the Company and to certain amendments to the terms of such agreement. The Discrete Technology Development Agreement provided that the expenses for all Discrete Development Activities were to be shared equally by the Company and Sanken on an annual basis (subject to any exceptions upon which the parties agreed to from time to time). As of March 26, 2021, the Company had accrued $614 included in amounts due to a related party under the Discrete Technology Development Agreement, which was paid in the first quarter of fiscal year 2022. The Discrete Technology Development Agreement terminated on March 31, 2021 in accordance with its terms. On March 28, 2020, the Company entered into an agreement to divest a majority of its ownership interest in PSL to Sanken, in order to better align with its fabless, asset-lite scalable manufacturing strategy (the “PSL Divestiture”). In addition, this also resulted in PSL taking over the Sanken distribution business at the same time. The Company continues to purchase in-process products from PSL. Purchases of various products from PSL totaled $13,129 and $26,509 for the three- and six-month periods ended September 24, 2021, respectively, and $9,967 and $21,890 for the three- and six-month periods ended September 25, 2020, respectively. For the three- and six-month periods ended September 25, 2020, these amounts include $1,700 and $3,500, respectively, of price support payments. The price support payments were for fiscal year 2021 only and no such payments are expected to be made in fiscal 2022. Accounts payable to PSL included in amounts due to a related party totaled $3,688 and $1,739 as of September 24, 2021 and March 26, 2021, respectively. Transactions involving Sanken Electric Europe Ltd. (“SEEL”) During fiscal year ended March 26, 2021 (and following the PSL Divestiture), Sanken, through PSL formed SEEL in order to cover its distribution business in Europe. The Company, in connection with the transition services agreement with Sanken and PSL, paid certain costs on behalf of them, and as such, had no related party accounts receivable from SEEL as of September 24, 2021. The Company had related party accounts receivable from SEEL of $1,272 as of March 26, 2021. Sublease Agreement In 2014, the Company, through one of its subsidiaries, entered into a sublease agreement with Sanken pursuant to which the subsidiary subleases from Sanken certain office building space in Japan. The sublease automatically renews on an annual basis unless either party provides notice to the other party and can otherwise be terminated by either party upon providing six months’ prior notice. The Company made aggregate payments of approximately $56 and $112 to Sanken under the sublease agreement during the three- and six-month periods ended September 24, 2021, respectively, and $58 and $115 during the three- and six-month periods ended September 25, 2020, respectively. Consulting Agreement In September 2018 and prior to Reza Kazerounian becoming a member of the Company’s board of directors, the Company entered into a board executive advisor agreement (the “Consulting Agreement”) with Mr. Kazerounian, pursuant to which the Company engaged Mr. Kazerounian to serve as executive advisor to the board of directors and the office of Chief Executive Officer. The Consulting Agreement provides for a fee payable to Mr. Kazerounian on a monthly basis in exchange for his services (which fee was reduced from $30 per month to $19 per month in connection with Mr. Kazerounian’s appointment to the board of directors in June 2018), as well as a grant of 12,000 shares of the Company’s Class L common stock and a signing bonus of $54 in connection with the execution of the Consulting Agreement. The Consulting Agreement provides that if Mr. Kazerounian’s employment is terminated by the board of directors, he will be entitled to a severance payment in the amount of $180 as well as a six-month vesting acceleration of his shares of Class L common stock. The board of directors and Mr. Kazerounian each have the right to terminate the Consulting Agreement at any time. During the three- and six-month periods ended September 24, 2021, the Company paid aggregate fees of $66 and $122, respectively, to Mr. Kazerounian pursuant to the Consulting Agreement. During the three- and six-month periods ended September 25, 2020, the Company paid aggregate fees of $90 and $180, respectively, to Mr. Kazerounian pursuant to the Consulting Agreement.

Summary of Significant Accounting Policies (Policies)	6 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 24, 2021
Accounting Policies [Abstract]
Use of Estimates	Use of Estimates The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets, liabilities, and disclosures of contingencies at the date of the unaudited consolidated financial statements and the reported amounts of net sales and expenses during the reporting period. Such estimates relate to useful lives of fixed and intangible assets, allowances for doubtful accounts and customer returns and sales allowances. Such estimates could also relate to the fair value of acquired assets and liabilities, including goodwill and intangible assets, net realizable value of inventory, accrued liabilities, the valuation of stock-based awards, deferred tax valuation allowances, and other reserves. On an ongoing basis, management evaluates its estimates. Actual results could differ from those estimates, and such differences may be material to the unaudited condensed consolidated financial statements.
Reclassifications	Reclassifications Certain reclassifications have been made to prior-period amounts to conform to current-period reporting classifications.
Concentrations of Credit Risk and Significant Customers	Concentrations of Credit Risk and Significant Customers Financial instruments that potentially subject the Company to concentrations of credit risk consist primarily of cash, cash equivalents and accounts receivable. The Company maintains its cash and cash equivalents with financial institutions that management believes to be of a high credit quality. To manage credit risk related to accounts receivables, the Company evaluates the creditworthiness of its customers and maintains allowances, to the extent necessary, for potential credit losses based upon the aging of its accounts receivable balances and known collection issues.
Recently Adopted Accounting Standards and Recently Issued Accounting Standards Not Yet Adopted	Recently Adopted Accounting Standards The Company qualifies as “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and has elected to “opt in” to the extended transition related to complying with new or revised accounting standards, which means that when a standard is issued or revised and it has different application dates for public and nonpublic companies, the Company will adopt the new or revised standard at the time nonpublic companies adopt the new or revised standard and will do so until such time that the Company either (i) irrevocably elects to “opt out” of such extended transition period or (ii) no longer qualifies as an emerging growth company. The Company may choose to early adopt any new or revised accounting standards whenever such early adoption is permitted for nonpublic companies. In February 2016, the Financial Accounting Standards Board (“FASB”) issued its new lease accounting guidance in Accounting Standards Update (“ASU”) 2016‑02, “Leases (Topic 842)” (“ASU 2016-02”), which is codified as Accounting Standard Codification (“ASC”) Topic 842 (“ASC 842”) and replaces ASC Topic 840, Leases (“ASC 840”). ASU 2016-02 and all subsequent amendments amend various aspects of existing guidance for leases and require significant additional quantitative and qualitative disclosures about lease arrangements. ASU 2016-02 requires lessees to recognize lease assets representing the right to use an underlying asset and lease liabilities representing the obligation to make lease payments over the lease term, measured on a discounted basis, for substantially all leases. ASU 2016-02 retains a distinction between finance leases and operating leases using classification criteria that are substantially similar to the previous lease guidance. Although the Company has elected to opt-in to the extended transition dates for new or revised accounting standards to align with nonpublic companies, the Company elected to early adopt ASU 2016-02 effective March 27, 2021. The Company used the optional transition method to the modified retrospective approach, which eliminates the requirement to restate the prior period financial statements. Under this transition provision, the Company has applied ASU 2016-02 to reporting periods beginning on March 27, 2021, while prior periods continue to be reported and disclosed in accordance with the legacy guidance under ASC 840. A number of practical expedients and policy elections are available under the new guidance to reduce the burden of adoption and ongoing compliance with ASC 842. The Company elected the “package of practical expedients”, which permitted the Company to retain lease classification and initial direct costs for any identified leases that existed prior to adoption of ASC 842. Under this transition guidance, the Company also did not reassess whether any existing contracts at March 27, 2021 are, or contain, leases and carried forward its initial determination under legacy lease guidance. The Company has elected not to adopt the “hindsight” practical expedient and, therefore, will measure the right-of-use (“ROU”) asset and lease liability using the remaining portion of the lease term at adoption on March 27, 2021. The Company made an accounting policy election available under the new lease standard to not recognize lease assets and lease liabilities for leases with a term of 12 months or less. For all other leases, the initial measurement of the lease liability is based on the present value of future lease payments over the lease term at the application date or the commencement date of the lease. Lease payments may include fixed rent escalation clauses or payments that depend on an index or a rate (such as the consumer price index) measured using the index or applicable rate at lease commencement. Subsequent changes in the index or rate and any other variable payments, such as market-rate base rent adjustments, are recognized as variable lease expense in the period incurred. Payments for terminating a lease are included in lease payments only when it is probable they will be incurred. To determine the present value of lease payments, the Company uses its incremental borrowing rate, as the leases generally do not have a readily determinable implicit discount rate. The Company applies judgment in assessing factors such as Company-specific credit risk, lease term, nature and quality of the underlying collateral, currency and economic environment in determining the lease-specific incremental borrowing rate. The carrying value of the ROU assets at the application date equals the lease liability adjusted for any initial direct costs incurred and lease payments made at or before the commencement date and for any lease incentives. The Company’s leases generally include a non-lease component representing additional services transferred to the Company. The Company has made an accounting policy election to account for lease and non-lease components in its contacts as a single lease component for all asset classes. The non-lease components are usually variable in nature and recorded in variable lease expense in the period incurred. Adoption of ASC 842 resulted in ROU assets of $18,403 and lease liabilities of $18,759 related to the Company’s operating leases at March 27, 2021. The Company does not have any leases classified as finance leases. The adoption of ASC 842 did not materially impact the Company’s consolidated net income or consolidated cash flows and did not result in a cumulative-effect adjustment to the opening balance of retained earnings. In June 2016, the FASB issued ASU No. 2016-13, “Measurement of Credit Losses on Financial Instruments” (“ASU 2016-13”), which adds an impairment model (known as the current expected credit loss (“CECL”) model) that is based on expected losses rather than incurred losses. Under the new guidance, an entity recognizes as an allowance its estimate of expected credit losses, which the FASB believes will result in more timely recognition of such losses. The ASU is also intended to reduce complexity by decreasing the number of credit impairment models that entities use to account for debt instruments. The Company adopted ASU 2016-13 effective March 27, 2021 and concluded that the standard update did not have a material impact on either the financial position, results of operations, cash flows, or related disclosures. There was no impact on beginning balance retained earnings upon adoption of this ASU. The Company is exposed to credit losses primarily through trade and other financing receivables arising from revenue transactions. The Company uses an aging schedule method to estimate current expected credit losses based on days of delinquency, including information about past events and current economic conditions. The Company’s accounts receivable is separated into two categories using a portfolio methodology to evaluate the allowance under the CECL impairment model based on sales categorization and similar credit quality and worthiness of the customers: original equipment manufacturers (“OEMs”) and distributors. The receivables in each category share similar risk characteristics. The change to the CECL impairment model resulted in an immaterial increase in the provision for expected credit losses compared to the allowance for doubtful accounts under the previous incurred loss method. The Company increases the allowance for expected credits losses when the Company determines all or a portion of a receivable is uncollectible. The Company recognizes recoveries as a decrease to the allowance for expected credit losses. For the three- and six-month periods ended September 24, 2021, no material changes in the allowance occurred. Recently Issued Accounting Standards Not Yet Adopted In May 2021, the FASB issued ASU No. 2021-04, Earnings Per Share (Topic 260), Debt—Modifications and Extinguishments (Subtopic 470-50), Compensation—Stock Compensation (Topic 718), and Derivatives and Hedging—Contracts in Entity’s Own Equity (Subtopic 815-40) (“ASU 2021-04”). ASU 2021-04 outlines how an entity should account for modifications made to equity-classified written call options, including stock options and warrants to purchase the entity’s own common stock. The guidance in the ASU requires an entity to treat a modification of an equity-classified written call option that does not cause the option to become liability-classified as an exchange of the original option for a new option. This guidance applies whether the modification is structured as an amendment to the terms and conditions of the equity-classified written call option or as termination of the original option and issuance of a new option. The guidance is effective prospectively for fiscal years beginning after December 15, 2021, including interim periods within those fiscal years. Early adoption is permitted, including in an interim period as of the beginning of the fiscal year that includes that interim period. The Company is currently in the process of evaluating the impact of this new guidance on the consolidated financial statements and the related disclosures.

Revenue from Contract with Customers (Tables)

6 Months Ended

Sep. 24, 2021

Revenue from Contract with Customer [Abstract]

Net Sales by Core End Market and Application

Net sales by application:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020

Automotive	$	126,031	$	89,479	$	259,554	$	165,857
Industrial	36,321		21,650		66,630		42,056
Other	31,258		25,520		55,568		43,737



Total net sales	$	193,610	$	136,649	$	381,752	$	251,650

Net Sales by Product

Net sales by product:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Power integrated circuits	$	65,523	$	50,271	$	132,195	$	91,870
Magnetic sensors	127,621		86,097		248,263		159,499
Photonics	466		281		1,294		281


Total net sales	$	193,610	$	136,649	$	381,752	$	251,650

Net Sales by Geography

Net sales by geography:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Americas:
United States	$	27,785	$	20,962	$	54,626	$	33,958
Other Americas	5,427		3,249		11,776		5,177
EMEA:
Europe	32,466		24,374		67,217		42,220
Asia:
Japan	37,165		22,511		72,618		46,131
Greater China	50,683		37,935		93,462		70,006
South Korea	19,746		12,515		41,679		26,127
Other Asia	20,338		15,103		40,374		28,031
Total net sales	$	193,610	$	136,649	$	381,752	$	251,650

Fair Value Measurements (Tables)

6 Months Ended

Sep. 24, 2021

Fair Value Disclosures [Abstract]

Fair Value, by Balance Sheet Grouping


	Fair Value Measurement at September 24, 2021 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market fund deposits	$	16,341	$	—	$	—	$	16,341
Restricted cash:
Money market fund deposits	7,105		—		—		7,105
Other assets, net (long-term):
Investments in marketable securities	$	5,287	$	—	$	—	$	5,287
Total assets	$	28,733	$	—	$	—	$	28,733
Liabilities:
Other long-term liabilities:
Contingent consideration	$	—	$	—	$	5,400	$	5,400
Total liabilities	$	—	$	—	$	5,400	$	5,400


	Fair Value Measurement at March 26, 2021 Using:
	Level 1		Level 2		Level 3		Total
Assets:
Cash equivalents:
Money market fund deposits	$	16,327	$	—	$	—	$	16,327
Restricted cash:
Money market fund deposits	6,661		—		—		6,661
Total assets	$	22,988	$	—	$	—	$	22,988
Liabilities:
Other long-term liabilities:
Contingent consideration	—		—		4,800		4,800
Total liabilities	$	—	$	—	$	4,800	$	4,800

Unrealized Gains and Losses on Marketable Securities with a Readily Determinable Fair Value

The following table represents the unrealized gains and losses on investments in marketable securities held with a readily determinable fair value for the six-month period ended September 24, 2021:



Net gains and losses recognized during the period on equity securities	$	978
Less: Net gains and losses recognized during the period on equity securities sold during the period	—
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting date	$	978

Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation

develops, manufactures and supplies photonic and advanced 3D imaging technologies (the “Voxtel Acquisition”), for the six-month period ended September 24, 2021:


	Level 3 Contingent Consideration
Balance at March 26, 2021	$	4,800
Change in fair value of contingent consideration	600

Balance at September 24, 2021	$	5,400

Trade Accounts Receivable, net (Tables)

6 Months Ended

Sep. 24, 2021

Receivables [Abstract]

Schedule of Trade Accounts Receivable, Net

Trade accounts receivable, net (including related party trade accounts receivable) consisted of the following:


	September 24, 2021		March 26, 2021
Trade accounts receivable	$	115,274	$	108,546
Less:
Provision for expected credit losses and allowance for doubtful accounts	(176)		(138)
Returns and sales allowances	(17,407)		(15,274)
Related party trade accounts receivable	(23,720)		(23,634)
Total	$	73,971	$	69,500

Schedule of Changes in Allowance for Doubtful Accounts and Returns and Sales Allowances

Changes in the Company’s allowance for doubtful accounts and returns and sales allowances were as follows:


Description	Allowance for Doubtful Accounts		Returns and Sales Allowances		Total
Balance at March 26, 2021	$	138	$	15,274	$	15,412
Charged to costs and expenses or revenue	38		82,365		82,403
Write-offs, net of recoveries	—		(80,232)		(80,232)
Balance at September 24, 2021	$	176	$	17,407	$	17,583


Description	Allowance for Doubtful Accounts		Returns and Sales Allowances		Total
Balance at March 27, 2020	$	288	$	17,185	$	17,473
Charged to costs and expenses or revenue	50		64,316		64,366
Write-offs, net of recoveries	—		(62,502)		(62,502)
Balance at September 25, 2020	$	338	$	18,999	$	19,337

Inventories (Tables)

6 Months Ended

Sep. 24, 2021

Inventory Disclosure [Abstract]

Schedule of Inventories

Inventories include material, labor and overhead and consisted of the following:


	September 24, 2021		March 26, 2021
Raw materials and supplies	$	10,265	$	9,629
Work in process	43,964		50,095
Finished goods	23,813		27,774

Total	$	78,042	$	87,498

Property, Plant and Equipment, net (Tables)

6 Months Ended

Sep. 24, 2021

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant, and Equipment

Property, plant and equipment, net is stated at cost, and consisted of the following:


	September 24, 2021		March 26, 2021
Land	$	16,227	$	16,602
Buildings, building improvements and leasehold improvements	56,992		56,911
Machinery and equipment	520,133		491,025
Office equipment	6,268		6,281
Construction in progress	16,947		29,201
Total	616,567		600,020
Less accumulated depreciation	(418,498)		(407,627)
Total	$	198,069	$	192,393

Schedule of Long-lived Assets

The geographic locations of the Company’s long-lived assets, net, based on physical location of the assets, as of September 24, 2021 and March 26, 2021 are as follows:


	September 24, 2021		March 26, 2021
United States	$	35,433	$	36,529
Philippines	155,564		148,374
Thailand	—		1,698
Other	7,407		7,190
Total	$	198,404	$	193,791

Goodwill and Intangible Assets (Tables)

6 Months Ended

Sep. 24, 2021

Goodwill and Intangible Assets Disclosure [Abstract]

Summary of Changes in Carrying Amount of Goodwill

The table below summarizes the changes in the carrying amount of goodwill as follows:


	Total
Balance at March 26, 2021	$	20,106

Currency translation	(13)
Balance at September 24, 2021	$	20,093

Schedule of Intangible Assets, Net

Intangible assets, net is as follows:


	September 24, 2021
Description	Gross		Accumulated Amortization		Net Carrying Amount		Weighted- Average Lives
Patents	$	34,616	$	13,799	$	20,817	10 years
Customer relationships	6,951		6,668		283		9 years
Process technology	13,100		1,197		11,903		12 years
Indefinite-lived and legacy process technology	4,050		1,650		2,400
Trademarks	200		44		156		5 years
Legacy trademarks	629		57		572
Other	32		32		—
Total	$	59,578	$	23,447	$	36,131


	March 26, 2021
Description	Gross		Accumulated Amortization		Net Carrying Amount		Weighted- Average Lives
Patents	$	32,751	$	12,307	$	20,444	10 years
Customer relationships	6,193		5,865		328		9 years
Process technology	13,100		651		12,449		12 years
Indefinite-lived and legacy process technology	4,050		1,650		2,400
Trademarks	200		24		176		5 years
Legacy trademarks	627		58		569
Other	32		32		—
Total	$	56,953	$	20,587	$	36,366

Schedule of Annual Amortization Expense

As of September 24, 2021, annual amortization expense of intangible assets for the next five fiscal years is expected to be as follows:


Remainder of 2022	$	2,326
2023	3,360
2024	3,241
2025	3,039
2026	2,823
Thereafter	21,342
Total	$	36,131

Other Assets, net (Tables)

6 Months Ended

Sep. 24, 2021

Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]

Schedule of Other Assets, Net

The composition of other assets, net is as follows:


	September 24, 2021		March 26, 2021
VAT receivables long-term, net	$	8,958	$	8,177
Income taxes receivable long-term	11,462		—
Investments in marketable securities (1)	5,287		—
Deposits	8,567		3,573
Prepaid contracts long-term	1,662		1,295
Deferred financing costs	99		149
Other	2,652		1,419
Total	$	38,687	$	14,613

Accrued Expenses and Other Current Liabilities (Tables)

6 Months Ended

Sep. 24, 2021

Payables and Accruals [Abstract]

Schedule of Accrued Expenses and Other Current Liabilities

The composition of accrued expenses and other current liabilities is as follows:


	September 24, 2021		March 26, 2021

Accrued management incentives	$	16,167	$	21,538
Accrued salaries and wages	16,838		15,060
Base acquisition purchase price due	2,000		14,588
Deposits on AMTC Facility	—		14,531
Accrued vacation	6,056		5,739
Accrued severance	497		572
Accrued professional fees	3,472		2,029
Accrued income taxes	1,487		514
Accrued utilities	622		623
Other current liabilities	4,910		3,738
Total	$	52,049	$	78,932

Leases (Tables)

6 Months Ended

Sep. 24, 2021

Leases [Abstract]

Schedule of Lease Costs and Other Information

Operating lease cost is recognized on a straight-line basis over the lease term. Information regarding the Company’s leases are as follows:


	Three-Month Period Ended			Six-Month Period Ended
	September 24, 2021				September 24, 2021
Lease costs:
Operating lease expense	$	1,154			$	2,302
Short term lease expense	87				141

Other information:
Operating cash flows from operating leases	$	1,244			$	2,474
Weighted-average remaining lease term – operating leases	5.71 years				5.71 years
Weighted-average discount rate – operating leases	4.6		%		4.6		%

Schedule of Lease Liability Maturity

As of September 24, 2021, expirations of lease obligations by fiscal year were as follows:


Remainder of 2022	$	2,137
2023	3,922
2024	3,526
2025	3,095
2026	2,623
Thereafter	4,463
Total undiscounted lease payments	$	19,766
Less: present value adjustment	(2,450)
Total operating lease liabilities	$	17,316

Schedule of Future Minimum Rental Payments

Future minimum lease payments for noncancellable operating leases as reported under the previous lease guidance as of March 26, 2021 are as follows:


2022	$	2,887
2023	2,726
2024	2,644
2025	2,172
2026	1,773
Thereafter	3,713
Total	$	15,915

Other Long-Term Liabilities (Tables)

6 Months Ended

Sep. 24, 2021

Other Liabilities Disclosure [Abstract]

Schedule of Other Long-Term Liabilities

The composition of other long-term liabilities is as follows:


	September 24, 2021		March 26, 2021

Accrued management incentives	$	614	$	628
Accrued retirement	10,669		10,656
Accrued contingent consideration	5,400		4,800
Provision for uncertain tax positions (net)	2,806		2,774
Other	—		275
Total	$	19,489	$	19,133

Retirement Plans (Tables)

6 Months Ended

Sep. 24, 2021

Retirement Benefits [Abstract]

Schedule of Expense Related to Defined Benefit Plan

Expense related to the non-United States (“U.S.”). defined benefit plan was as follows:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Service cost	$	371	$	277	$	754	$	547
Interest cost	161		156		327		308
Expected return on plan assets	(76)		(74)		(155)		(152)


Amortization of prior service cost	—		2		—		4
Actuarial loss	52		45		105		79
Net periodic pension expense	$	508	$	406	$	1,031	$	786

Fair Value of Entity's Plan Assets


	Fair Value at September 24, 2021		Level 1		Level 2		Level 3
Assets of non-U.S. defined benefit plan:
Government securities	$	1,726	$	1,726	$	—	$	—
Unit investment trust fund	1,053		—		1,053		—
Loans	620		—		—		620
Bonds	867		—		867		—
Stocks and other investments	2,438		1,340		2		1,096
Total	$	6,704	$	3,066	$	1,922	$	1,716


	Fair Value at March 26, 2021		Level 1		Level 2		Level 3
Assets of non-U.S. defined benefit plan:
Government securities	$	1,646	$	1,646	$	—	$	—
Unit investment trust fund	1,221		—		1,221		—
Loans	584		—		—		584
Bonds	1,112		—		1,112		—
Stocks and other investments	3,081		1,947		1		1,133
Total	$	7,644	$	3,593	$	2,334	$	1,717

Schedule of Changes in Fair Value of Level 3 Plan Assets

The following table shows the change in fair value of Level 3 plan assets for the six-month period ended September 24, 2021:


	Level 3 Non-U.S. Defined Plan Assets
	Loans		Stocks
Balance at March 26, 2021	$	584	$	1,133
Additions during the year	273		—
Redemptions during the year	(214)		—
Revaluation of equity securities	(1)		—
Change in foreign currency exchange rates	(22)		(37)
Balance at September 24, 2021	$	620	$	1,096

Net Income per Share (Tables)

6 Months Ended

Sep. 24, 2021

Earnings Per Share [Abstract]

Schedule of Computation of Net (Loss) Income per Share and Unaudited Pro Forma Net Income per Share


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Net income attributable to Allegro MicroSystems, Inc.	$	33,186	$	9,584	$	60,855	$	14,404
Net income attributable to common stockholders	33,223		9,618		60,930		14,472
Basic weighted average shares of common stock	189,673,788		10,000,000		189,629,535		10,000,000
Dilutive effect of common stock equivalents	2,002,634		—		1,786,715		—
Diluted weighted average shares of common stock	191,676,422		10,000,000		191,416,250		10,000,000
Basic net income attributable to Allegro MicroSystems, Inc. per share	$	0.17	$	0.96	$	0.32	$	1.44
Basic net income attributable to common stockholders per share	$	0.18	$	0.96	$	0.32	$	1.45
Diluted net income attributable to Allegro MicroSystems, Inc. per share	$	0.17	$	0.96	$	0.32	$	1.44
Diluted net income attributable to common stockholders per share	$	0.17	$	0.96	$	0.32	$	1.45

Schedule of Issuable Weighted Average Share Information

The following table represents issuable weighted average share information for the respective periods:


	Three-Month Period Ended		Six-Month Period Ended
	September 24, 2021	September 25, 2020	September 24, 2021	September 25, 2020
Restricted stock units	1,026,069	—	922,968	—
Performance stock units	976,565	—	863,747	—


Total	2,002,634	—	1,786,715	—

Common Stock and Stock-Based Compensation (Tables)

6 Months Ended

Sep. 24, 2021

Share-based Payment Arrangement [Abstract]

Schedule of Stock-Based Compensation Expense

The Company recorded stock-based compensation expense in the following expense categories of its unaudited consolidated statements of operations:


	Three-Month Period Ended				Six-Month Period Ended
	September 24, 2021		September 25, 2020		September 24, 2021		September 25, 2020
Cost of sales	$	722	$	53	$	1,250	$	150
Research and development	1,043		32		1,795		53
Selling, general and administrative	4,431		495		7,982		822
Total stock-based compensation	$	6,196	$	580	$	11,027	$	1,025

Income Taxes (Tables)

6 Months Ended

Sep. 24, 2021

Income Tax Disclosure [Abstract]

Schedule of Tax (Benefit) Provision

The Company recorded the following tax (benefit) provision in its unaudited consolidated statements of operations:


	Three-Month Period Ended						Six-Month Period Ended
	September 24, 2021			September 25, 2020			September 24, 2021			September 25, 2020
Operating taxes	$	6,150		$	1,589		$	11,268		$	2,405
Discrete tax items	(7)			493			(862)			205
Provision for income taxes	$	6,143		$	2,082		$	10,406		$	2,610
Annual operating tax rate	15.6		%	13.6		%	15.8		%	14.1		%
Effective tax rate	15.6		%	17.8		%	14.6		%	15.3		%

Nature of the Business and Basis of Presentation - Additional Information (Details)	Sep. 24, 2021 location continent
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of locations \| location	16
Number of continents on which entity operates \| continent	4

Summary of Significant Accounting Policies - Concentrations of Credit Risk and Significant Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020	Mar. 26, 2021	Mar. 27, 2021
Concentration Risk [Line Items]
Operating lease right-of-use assets	$ 17,054		$ 17,054		$ 0
Total operating lease liabilities	$ 17,316		$ 17,316
Accounting Standards Update 2016-02
Concentration Risk [Line Items]
Operating lease right-of-use assets						$ 18,403
Total operating lease liabilities						$ 18,759
Revenue Benchmark \| Geographic Concentration Risk \| Non-US
Concentration Risk [Line Items]
Concentration risk, percentage	85.60%	84.70%	85.70%	86.50%
Revenue Benchmark \| Geographic Concentration Risk \| Greater China
Concentration Risk [Line Items]
Concentration risk, percentage	26.20%	27.80%	24.50%	27.80%
Revenue Benchmark \| Geographic Concentration Risk \| Japan
Concentration Risk [Line Items]
Concentration risk, percentage	19.20%	16.40%	19.00%	18.30%
Revenue Benchmark \| Geographic Concentration Risk \| South Korea
Concentration Risk [Line Items]
Concentration risk, percentage	10.20%		10.90%	10.40%
Sanken \| Trade Accounts Receivable \| Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage			24.30%		22.70%
Sanken \| Revenue Benchmark \| Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk, percentage	19.20%	16.50%	19.00%	18.30%

Revenue from Contract with Customers - Net Sales by Application (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Disaggregation of Revenue [Line Items]
Total net sales	$ 193,610	$ 136,649	$ 381,752	$ 251,650
Automotive
Disaggregation of Revenue [Line Items]
Total net sales	126,031	89,479	259,554	165,857
Industrial
Disaggregation of Revenue [Line Items]
Total net sales	36,321	21,650	66,630	42,056
Other
Disaggregation of Revenue [Line Items]
Total net sales	$ 31,258	$ 25,520	$ 55,568	$ 43,737

- Definition

Amount, excluding tax collected from customer, of revenue from satisfaction of performance obligation by transferring promised good or service to customer. Tax collected from customer is tax assessed by governmental authority that is both imposed on and concurrent with specific revenue-producing transaction, including, but not limited to, sales, use, value added and excise.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 30
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8906-108599

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 40
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9031-108599

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 41
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9038-108599

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 32
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8933-108599

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130543-203045

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 22
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e8736-108599

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 280
-SubTopic 10
-Section 50
-Paragraph 42
-URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=121604090&loc=SL49130545-203045

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 924
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 11.L)
-URI http://asc.fasb.org/extlink&oid=6472922&loc=d3e499488-122856

+ Details

Revenue from Contract with Customers - Net Sales by Product (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Disaggregation of Revenue [Line Items]
Total net sales	$ 193,610	$ 136,649	$ 381,752	$ 251,650
Power integrated circuits
Disaggregation of Revenue [Line Items]
Total net sales	65,523	50,271	132,195	91,870
Magnetic sensors
Disaggregation of Revenue [Line Items]
Total net sales	127,621	86,097	248,263	159,499
Photonics
Disaggregation of Revenue [Line Items]
Total net sales	$ 466	$ 281	$ 1,294	$ 281

- Definition

+ References

+ Details

Revenue from Contract with Customers - Net Sales by Geography (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Disaggregation of Revenue [Line Items]
Total net sales	$ 193,610	$ 136,649	$ 381,752	$ 251,650
United States
Disaggregation of Revenue [Line Items]
Total net sales	27,785	20,962	54,626	33,958
Other Americas
Disaggregation of Revenue [Line Items]
Total net sales	5,427	3,249	11,776	5,177
Europe
Disaggregation of Revenue [Line Items]
Total net sales	32,466	24,374	67,217	42,220
Japan
Disaggregation of Revenue [Line Items]
Total net sales	37,165	22,511	72,618	46,131
Greater China
Disaggregation of Revenue [Line Items]
Total net sales	50,683	37,935	93,462	70,006
South Korea
Disaggregation of Revenue [Line Items]
Total net sales	19,746	12,515	41,679	26,127
Other Asia
Disaggregation of Revenue [Line Items]
Total net sales	$ 20,338	$ 15,103	$ 40,374	$ 28,031

- Definition

+ References

+ Details

Revenue from Contract with Customers - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Mar. 26, 2021
Revenue from Contract with Customer [Abstract]
Trade accounts receivable, returns, credits issued, and price protection adjustments, current	$ 17,583		$ 15,412
Trade accounts receivable, returns, credits issued, and price protection adjustments expense (credit)	$ 2,171	$ 1,864

Fair Value Measurements - Assets And Liabilities Measured At Fair Value (Details) - Fair Value, Recurring - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Assets:
Total assets	$ 28,733	$ 22,988
Liabilities:
Contingent consideration	5,400	4,800
Total liabilities	5,400	4,800
Level 1
Assets:
Total assets	28,733	22,988
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 2
Assets:
Total assets	0	0
Liabilities:
Contingent consideration	0	0
Total liabilities	0	0
Level 3
Assets:
Total assets	0	0
Liabilities:
Contingent consideration	5,400	4,800
Total liabilities	5,400	4,800
Money market fund deposits
Assets:
Cash and cash equivalents	16,341	16,327
Restricted cash	7,105	6,661
Investments in marketable securities	5,287
Money market fund deposits \| Level 1
Assets:
Cash and cash equivalents	16,341	16,327
Restricted cash	7,105	6,661
Investments in marketable securities	5,287
Money market fund deposits \| Level 2
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	0
Investments in marketable securities	0
Money market fund deposits \| Level 3
Assets:
Cash and cash equivalents	0	0
Restricted cash	0	$ 0
Investments in marketable securities	$ 0

Fair Value Measurements - Unrealized Gains and Losses on Marketable Securities with a Readily Determinable Fair Value (Details) $ in Thousands	6 Months Ended
	Sep. 24, 2021 USD ($)
Fair Value Disclosures [Abstract]
Net gains and losses recognized during the period on equity securities	$ 978
Less: Net gains and losses recognized during the period on equity securities sold during the period	0
Unrealized gains and losses recognized during the reporting period on equity securities still held at the reporting date	$ 978

Fair Value Measurements - Narrative (Details) $ in Thousands	6 Months Ended
	Sep. 24, 2021 USD ($)
Fair Value Disclosures [Abstract]
Unrealized foreign currency exchange losses on equity securities	$ 25

Fair Value Measurements - Change in Fair Value of Level 3 Contingent Consideration (Details) - Fair Value, Recurring - Level 3 - Contingent Consideration Liability $ in Thousands	6 Months Ended
	Sep. 24, 2021 USD ($)
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 4,800
Change in fair value of contingent consideration	600
Ending balance	$ 5,400

Trade Accounts Receivable, net - Summary of Trade Accounts Receivable, net (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021	Sep. 25, 2020	Mar. 27, 2020
Receivables [Abstract]
Trade accounts receivable	$ 115,274	$ 108,546
Less:
Provision for expected credit losses and allowance for doubtful accounts	(176)	(138)	$ (338)	$ (288)
Returns and sales allowances	(17,407)	(15,274)	$ (18,999)	$ (17,185)
Related party trade accounts receivable	(23,720)	(23,634)
Trade accounts receivable, net	$ 73,971	$ 69,500

Trade Accounts Receivable, net - Schedule of Changes in Allowance For Doubtful Accounts and Sales Returns and Sales Allowances (Details) - USD ($) $ in Thousands	6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020
Allowance for Doubtful Accounts
Balance at the beginning of the period	$ 138	$ 288
Charged to costs and expenses or revenue	38	50
Write-offs, net of recoveries	0	0
Balance at the end of the period	176	338
Returns and Sales Allowances
Balance at the beginning of the period	15,274	17,185
Charged to costs and expenses or revenue	82,365	64,316
Write-offs, net of recoveries	(80,232)	(62,502)
Balance at the end of the period	17,407	18,999
Total
Balance at the beginning of the period	15,412	17,473
Charged to costs and expenses or revenue	82,403	64,366
Write-offs, net of recoveries	(80,232)	(62,502)
Balance at the end of the period	$ 17,583	$ 19,337

Inventories - Schedule of Inventories (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Inventory Disclosure [Abstract]
Raw materials and supplies	$ 10,265	$ 9,629
Work in process	43,964	50,095
Finished goods	23,813	27,774
Total	$ 78,042	$ 87,498

Inventories - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Inventories - Narrative (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Inventory Disclosure [Abstract]
Recorded inventory provisions	$ 1,852	$ 490	$ 5,041	$ 2,073
Disposal Group, Not Discontinued Operations \| Voxtel Product Line
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Recorded inventory provisions	$ 271		$ 3,106

Assets Held for Sale (Details) - Disposal Group, Held-for-sale, Not Discontinued Operations - AMTC Facility $ in Thousands	Aug. 03, 2021 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses	$ 27,405
Gain on final disposition	$ 370

Property, Plant and Equipment, net - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Property, Plant and Equipment [Line Items]
Total	$ 616,567	$ 600,020
Less accumulated depreciation	(418,498)	(407,627)
Total	198,069	192,393
Land
Property, Plant and Equipment [Line Items]
Total	16,227	16,602
Buildings, building improvements and leasehold improvements
Property, Plant and Equipment [Line Items]
Total	56,992	56,911
Machinery and equipment
Property, Plant and Equipment [Line Items]
Total	520,133	491,025
Office equipment
Property, Plant and Equipment [Line Items]
Total	6,268	6,281
Construction in progress
Property, Plant and Equipment [Line Items]
Total	$ 16,947	$ 29,201

Property, Plant and Equipment, net - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 11,222	$ 11,797	$ 22,342	$ 22,606
Prepaid tooling costs
Property, Plant and Equipment [Line Items]
Amortization expense	$ 33	$ 19	$ 66	$ 36

Property, Plant and Equipment, net - Schedule of Long Lived Assets (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	$ 198,404	$ 193,791
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	35,433	36,529
Philippines
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	155,564	148,374
Thailand
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	0	1,698
Other
Revenues from External Customers and Long-Lived Assets [Line Items]
Total	$ 7,407	$ 7,190

Goodwill and Intangible Assets - Summary of Changes in Carrying Amount of Goodwill (Details) $ in Thousands	6 Months Ended
	Sep. 24, 2021 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 20,106
Currency translation	(13)
Ending balance	$ 20,093

Goodwill and Intangible Assets - Schedule of Intangible Assets, Net (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 25, 2021	Sep. 24, 2021	Mar. 26, 2021
Finite-Lived Intangible Assets [Line Items]
Gross		$ 59,578	$ 56,953
Accumulated Amortization		23,447	20,587
Net Carrying Amount		36,131	36,366
Patents
Finite-Lived Intangible Assets [Line Items]
Gross		34,616	32,751
Accumulated Amortization		13,799	12,307
Net Carrying Amount		$ 20,817	20,444
Weighted- Average Lives	10 years	10 years
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross		$ 6,951	6,193
Accumulated Amortization		6,668	5,865
Net Carrying Amount		$ 283	328
Weighted- Average Lives	9 years	9 years
Process technology
Finite-Lived Intangible Assets [Line Items]
Gross		$ 13,100	13,100
Accumulated Amortization		1,197	651
Net Carrying Amount		$ 11,903	12,449
Weighted- Average Lives	12 years	12 years
Indefinite-lived and legacy process technology
Finite-Lived Intangible Assets [Line Items]
Gross		$ 4,050	4,050
Accumulated Amortization		1,650	1,650
Net Carrying Amount		2,400	2,400
Trademarks
Finite-Lived Intangible Assets [Line Items]
Gross		200	200
Accumulated Amortization		44	24
Net Carrying Amount		$ 156	176
Weighted- Average Lives	5 years	5 years
Legacy trademarks
Finite-Lived Intangible Assets [Line Items]
Gross		$ 629	627
Accumulated Amortization		57	58
Net Carrying Amount		572	569
Other
Finite-Lived Intangible Assets [Line Items]
Gross		32	32
Accumulated Amortization		32	32
Net Carrying Amount		$ 0	$ 0

Goodwill and Intangible Assets - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Sep. 24, 2021	Jun. 25, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets amortization expense	$ 1,084		$ 671	$ 2,103	$ 1,384
Patents
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated useful life		10 years		10 years

Goodwill and Intangible Assets - Future Amortization Expense (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Goodwill and Intangible Assets Disclosure [Abstract]
Remainder of 2022	$ 2,326
2023	3,360
2024	3,241
2025	3,039
2026	2,823
Thereafter	21,342
Net Carrying Amount	$ 36,131	$ 36,366

Other Assets, net (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
VAT receivables long-term, net	$ 8,958	$ 8,177
Income taxes receivable long-term	11,462	0
Investments in marketable securities	5,287	0
Deposits	8,567	3,573
Prepaid contracts long-term	1,662	1,295
Deferred financing costs	99	149
Other	2,652	1,419
Total	$ 38,687	$ 14,613

Accrued Expenses and Other Current Liabilities (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Payables and Accruals [Abstract]
Accrued management incentives	$ 16,167	$ 21,538
Accrued salaries and wages	16,838	15,060
Base acquisition purchase price due	2,000	14,588
Deposits on AMTC Facility	0	14,531
Accrued vacation	6,056	5,739
Accrued severance	497	572
Accrued professional fees	3,472	2,029
Accrued income taxes	1,487	514
Accrued utilities	622	623
Other current liabilities	4,910	3,738
Total	$ 52,049	$ 78,932

Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Leases - Narrative (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Lessee, Lease, Description [Line Items]
Rent expense	$ 1,537	$ 1,122	$ 2,772	$ 2,305
Minimum
Lessee, Lease, Description [Line Items]
Operating lease agreement term	1 year		1 year
Maximum
Lessee, Lease, Description [Line Items]
Operating lease agreement term	11 years		11 years

Leases - Schedule of Lease Costs and Other Information (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Sep. 24, 2021 USD ($)	Sep. 24, 2021 USD ($)
Lease costs:
Operating lease expense	$ 1,154	$ 2,302
Short term lease expense	87	141
Other information:
Operating cash flows from operating leases	$ 1,244	$ 2,474
Weighted-average remaining lease term – operating leases	5 years 8 months 15 days	5 years 8 months 15 days
Weighted-average discount rate – operating leases	4.60%	4.60%

Leases - Schedule of Lease Liability Maturity (Details) $ in Thousands	Sep. 24, 2021 USD ($)
Leases [Abstract]
Remainder of 2022	$ 2,137
2023	3,922
2024	3,526
2025	3,095
2026	2,623
Thereafter	4,463
Total undiscounted lease payments	19,766
Less: present value adjustment	(2,450)
Total operating lease liabilities	$ 17,316

Leases - Schedule of Future Minimum Rental Payments (Details) $ in Thousands	Mar. 26, 2021 USD ($)
Leases [Abstract]
2022	$ 2,887
2023	2,726
2024	2,644
2025	2,172
2026	1,773
Thereafter	3,713
Total	$ 15,915

Debt and Other Borrowings (Details)	Sep. 30, 2020 USD ($)	Sep. 24, 2021 USD ($)	Mar. 26, 2021 USD ($)	Nov. 26, 2019 PHP (₱)	Nov. 20, 2019 PHP (₱)
Term Loan Facility \| Line of Credit
Line of Credit Facility [Line Items]
Outstanding balance		$ 25,000,000	$ 25,000,000
Term Loan Facility \| Credit Suisse AG, Cayman Islands Branch
Line of Credit Facility [Line Items]
Maximum borrowing capacity	$ 325,000,000
Deferred financing costs	9,374,000
Senior Secured Revolving Credit Facility \| Mizuho Bank, Ltd
Line of Credit Facility [Line Items]
Maximum borrowing capacity	50,000,000
Interest rate at period end		4.25%
Outstanding balance		$ 0	0
Deferred financing costs	$ 300,000
Unamortized deferred financing costs		199,000
Senior Secured Revolving Credit Facility \| Mizuho Bank, Ltd \| London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Interest rate floor	0.005
Senior Secured Revolving Credit Facility \| Mizuho Bank, Ltd \| Minimum \| London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	3.75%
Senior Secured Revolving Credit Facility \| Mizuho Bank, Ltd \| Maximum \| London Interbank Offered Rate (LIBOR)
Line of Credit Facility [Line Items]
Basis spread on variable rate	4.00%
Unsecured Revolving Credit Facilities \| Line-of-Credit Agreement Expiring August 31, 2021 \| Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		1,796,000		₱ 60,000,000
Outstanding balance		0	0
Unsecured Revolving Credit Facilities \| Line-of-Credit Agreement Expiring June 30, 2021 \| Line of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity		2,246,000			₱ 75,000,000
Outstanding balance		$ 0	$ 0

Other Long-Term Liabilities (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Other Liabilities Disclosure [Abstract]
Accrued management incentives	$ 614	$ 628
Accrued retirement	10,669	10,656
Accrued contingent consideration	5,400	4,800
Provision for uncertain tax positions (net)	2,806	2,774
Other	0	275
Total	$ 19,489	$ 19,133

Retirement Plans - Schedule of Expense Related to Defined Benefit Plan (Details) - Pension Plan - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 371	$ 277	$ 754	$ 547
Interest cost	161	156	327	308
Expected return on plan assets	(76)	(74)	(155)	(152)
Amortization of prior service cost	0	2	0	4
Actuarial loss	52	45	105	79
Net periodic pension expense	$ 508	$ 406	$ 1,031	$ 786

Retirement Plans - Fair Value of Entity's Plan Assets (Details) - Pension Plan - USD ($) $ in Thousands	Sep. 24, 2021	Mar. 26, 2021
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	$ 6,704	$ 7,644
Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	3,066	3,593
Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,922	2,334
Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,716	1,717
Government securities
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,726	1,646
Government securities \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,726	1,646
Government securities \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Government securities \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Unit investment trust fund
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,053	1,221
Unit investment trust fund \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Unit investment trust fund \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,053	1,221
Unit investment trust fund \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Loans
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	620	584
Loans \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Loans \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Loans \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	620	584
Bonds
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	867	1,112
Bonds \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Bonds \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	867	1,112
Bonds \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	0	0
Stocks and other investments
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	2,438	3,081
Stocks and other investments \| Level 1
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	1,340	1,947
Stocks and other investments \| Level 2
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	2	1
Stocks and other investments \| Level 3
Defined Benefit Plan Disclosure [Line Items]
Assets of non-U.S. defined benefit plan	$ 1,096	$ 1,133

Retirement Plans - Schedule of Changes in Fair Value of Level 3 Plan Assets (Details) - Pension Plan $ in Thousands	6 Months Ended
	Sep. 24, 2021 USD ($)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	$ 7,644
Ending balance	6,704
Loans
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	584
Ending balance	620
Level 3
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	1,717
Ending balance	1,716
Level 3 \| Loans
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	584
Additions during the year	273
Redemptions during the year	(214)
Revaluation of equity securities	(1)
Change in foreign currency exchange rates	(22)
Ending balance	620
Level 3 \| Stocks
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Beginning balance	1,133
Additions during the year	0
Redemptions during the year	0
Revaluation of equity securities	0
Change in foreign currency exchange rates	(37)
Ending balance	$ 1,096

Retirement Plans - Narrative (Details) £ in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021 USD ($)	Sep. 25, 2020 USD ($)	Sep. 24, 2021 USD ($)	Sep. 25, 2020 USD ($)	Sep. 24, 2021 GBP (£)	Mar. 26, 2021 USD ($)	Mar. 26, 2021 GBP (£)
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Company contributions	$ 343	$ 247	$ 696	$ 487
Expected contributions in current fiscal year	943		$ 943
Other Defined Benefit Plans \| Pension Promise
Defined Benefit Plan Disclosure [Line Items]
Retirement age			65 years
Other assets, net	1,087		$ 1,087		£ 797	$ 1,272	£ 928
Accrued retirement, other long-term liabilities	1,087		$ 1,087		£ 797	$ 1,272	£ 928
Defined Contribution Plan
Defined Benefit Plan Disclosure [Line Items]
Maximum employee contribution			50.00%
Employer matching contribution			100.00%
Maximum employer contribution			5.00%
Total contributions	1,089	1,040	$ 2,345	2,069
Defined Contribution Plan \| 401(K) Plan
Defined Benefit Plan Disclosure [Line Items]
Maximum employee contribution			35.00%
Vesting percentage			100.00%
Defined Contribution Plan \| AME Plan
Defined Benefit Plan Disclosure [Line Items]
Total contributions	$ 211	$ 206	$ 429	$ 385

Commitment and Contingencies (Details) - USD ($)	Sep. 24, 2021	Mar. 26, 2021
Commitments and Contingencies Disclosure [Abstract]
Self insurance accruals	$ 660,000	$ 1,518,000
Indemnification accruals	0	0
Environmental accruals	$ 0	$ 0

Net Income per Share - Narrative (Details)			3 Months Ended		6 Months Ended
Net Income per Share - Narrative (Details)	Nov. 02, 2020 shares	Nov. 01, 2020	Sep. 24, 2021 shares	Sep. 25, 2020 shares	Sep. 24, 2021 shares	Sep. 25, 2020 shares
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares issued upon conversion, including shares withheld for tax withholding obligation (in shares)	166,500,000
Diluted weighted average shares of common stock (in shares)			191,676,422	10,000,000	191,416,250	10,000,000
Employee stock purchase plan
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Antidilutive securities excluded from computation of net income per share (in shares)			1,567	0	6,012	0
Common Class A
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion rate	15.822
Shares returned for tax payments made on behalf of holders of common stock (in shares)	2,066,508
Common Class A \| Common Stock
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Priority dividend rate		8.00%
Annualized return on capital, triggering percent, remaining distributions split between Class A and Class L shareholders		8.00%
Common Class L
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Conversion rate	13.010
Shares returned for tax payments made on behalf of holders of common stock (in shares)	1,766

Net Income per Share - Schedule of Computation of Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Earnings Per Share [Abstract]
Net income attributable to Allegro MicroSystems, Inc.	$ 33,186	$ 9,584	$ 60,855	$ 14,404
Net (loss) income attributable to common stockholders, basic	33,223	9,618	60,930	14,472
Net (loss) income attributable to common stockholders, diluted	$ 33,223	$ 9,618	$ 60,930	$ 14,472
Basic weighted average shares of common stock (in shares)	189,673,788	10,000,000	189,629,535	10,000,000
Dilutive effect of common stock equivalents (in shares)	2,002,634	0	1,786,715	0
Diluted weighted average common shares (in shares)	191,676,422	10,000,000	191,416,250	10,000,000
Basic net income attributable to Allegro MicroSystems, Inc. per share (in dollars per share)	$ 0.17	$ 0.96	$ 0.32	$ 1.44
Basic net income attributable to common stockholders per share (in dollars per share)	0.18	0.96	0.32	1.45
Diluted net income attributable to Allegro MicroSystems, Inc. per share (in dollars per share)	0.17	0.96	0.32	1.44
Diluted net income attributable to common stockholders per share (in dollars per share)	$ 0.17	$ 0.96	$ 0.32	$ 1.45

Net Income per Share - Schedule of Issuable Weighted Average Share Information (Details) - shares	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect of common stock equivalents (in shares)	2,002,634	0	1,786,715	0
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect of common stock equivalents (in shares)	1,026,069	0	922,968	0
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dilutive effect of common stock equivalents (in shares)	976,565	0	863,747	0

Common Stock and Stock-Based Compensation - Narrative (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Sep. 24, 2021 USD ($) $ / shares shares
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Grants in period (in shares)	960,031
Grant date fair value (in dollars per share) \| $ / shares	$ 24.96
Stock-based compensation expense not yet recorded \| $	$ 29,231
Weighted-average remaining contractual life	1 year 6 months 25 days
Vested during period (in shares)	64,583
Performance stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense not yet recorded \| $	$ 16,865
Weighted-average remaining contractual life	2 years 10 days
Vested during period (in shares)	0
Intrinsic value, vested \| $	$ 38,211
Performance stock units \| Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Inclusion percentage of target goals	100.00%
Performance stock units \| Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Inclusion percentage of target goals	200.00%
Restricted Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average remaining contractual life	1 year 3 months 29 days
Vested during period (in shares)	59,201
Cancelled (in shares)	9,757
Unvested shares of restricted commons stock (in shares)	337,369
Weighted-average grant date fair value (in dollars per share) \| $ / shares	$ 14.00

Common Stock and Stock-Based Compensation - Schedule of Stock-Based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 6,196	$ 580	$ 11,027	$ 1,025
Cost of sales
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	722	53	1,250	150
Research and development
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	1,043	32	1,795	53
Selling, general and administrative
Share-based Payment Arrangement, Expensed and Capitalized, Amount [Line Items]
Stock-based compensation	$ 4,431	$ 495	$ 7,982	$ 822

Income Taxes - Schedule of Tax Provision (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Sep. 24, 2021 USD ($)	Sep. 25, 2020 USD ($)	Sep. 24, 2021 USD ($)	Sep. 25, 2020 USD ($)
Income Tax Disclosure [Abstract]
Operating taxes	$ 6,150	$ 1,589	$ 11,268	$ 2,405
Discrete tax items	(7)	493	(862)	205
Provision for income taxes	$ 6,143	$ 2,082	$ 10,406	$ 2,610
Annual operating tax rate	0.156	0.136	0.158	0.141
Effective tax rate	15.60%	17.80%	14.60%	15.30%

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Income Taxes - Narrative (Details) - USD ($) $ in Thousands	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020
Income Tax Disclosure [Abstract]
Provision for income taxes	$ 6,143	$ 2,082	$ 10,406	$ 2,610
Effective tax rate	15.60%	17.80%	14.60%	15.30%

- Definition

Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

+ References + Details

Related Party Transactions (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Sep. 30, 2018	Sep. 24, 2021	Sep. 25, 2020	Sep. 24, 2021	Sep. 25, 2020	Mar. 26, 2021	Jun. 30, 2018	May 31, 2018
Related Party Transaction [Line Items]
Total net sales		$ 193,610	$ 136,649	$ 381,752	$ 251,650
Trade accounts receivable from related party		23,720		23,720		$ 23,634
Amounts due to related party		3,686		3,686		2,353
Rent expense		1,537	1,122	2,772	2,305
Related Party Revenue
Related Party Transaction [Line Items]
Total net sales		37,165	22,511	72,618	46,131
Sanken
Related Party Transaction [Line Items]
Trade accounts receivable from related party		23,720		23,720		21,595
Other accounts receivable from related party		133		$ 133		198
Option to terminate, period of notice				6 months
Rent expense		56	58	$ 112	115
Sanken \| Related Party Revenue
Related Party Transaction [Line Items]
Total net sales		37,165	22,511	72,618	46,131
PSL
Related Party Transaction [Line Items]
Amounts due to related party		3,688		3,688		1,739
Purchases from related party		13,129	9,967	26,509	21,890
PSL \| IC Technology Development Agreement
Related Party Transaction [Line Items]
Fees received		0	0	0	0
Fees paid		0	0	0	0
PSL \| Discrete Technology Development Agreement
Related Party Transaction [Line Items]
Amounts due to related party						614
PSL \| Price Support Payment
Related Party Transaction [Line Items]
Purchases from related party			1,700		3,500
Sanken Electric Europe Ltd.
Related Party Transaction [Line Items]
Trade accounts receivable from related party		0		0		$ 1,272
Director
Related Party Transaction [Line Items]
Fees paid		$ 66	$ 90	$ 122	$ 180
Monthly fee payable							$ 19	$ 30
Signing fee	$ 54
Severance payment if terminated	$ 180
Accelerated vesting, acceleration period	6 months
Director \| Common Class L
Related Party Transaction [Line Items]
Shares granted (in shares)	12,000,000

Label	Element	Value
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	$ 6,661,000
Restricted Cash and Cash Equivalents	us-gaap_RestrictedCashAndCashEquivalents	$ 5,385,000