Cover Page - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Mar. 27, 2026 |
May 18, 2026 |
Sep. 26, 2025 |
|
| Cover [Abstract] | |||
| Document Type | 10-K | ||
| Document Annual Report | true | ||
| Document Period End Date | Mar. 27, 2026 | ||
| Current Fiscal Year End Date | --03-27 | ||
| 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 Well-known Seasoned Issuer | Yes | ||
| Entity Voluntary Filers | No | ||
| Entity Current Reporting Status | Yes | ||
| Entity Interactive Data Current | Yes | ||
| Entity Filer Category | Large Accelerated Filer | ||
| Entity Small Business | false | ||
| Entity Emerging Growth Company | false | ||
| ICFR Auditor Attestation Flag | true | ||
| Entity Shell Company | false | ||
| Entity Public Float | $ 3,703,521,114 | ||
| Entity Common Stock, Shares Outstanding (in shares) | 186,222,406 | ||
| Documents Incorporated by Reference | Portions of the registrant’s proxy statement for its 2026 Annual Meeting of Stockholders to be filed pursuant to Regulation 14A within 120 days of the end of the registrant’s fiscal year ended March 27, 2026 are incorporated by reference into Part III of this Annual Report on Form 10-K to the extent stated herein. |
||
| Entity Central Index Key | 0000866291 | ||
| Amendment Flag | false | ||
| Document Fiscal Year Focus | 2026 | ||
| Document Fiscal Period Focus | FY | ||
| Document Financial Statement Error Correction [Flag] | false | ||
| Auditor Name | PricewaterhouseCoopers LLP | ||
| Auditor Firm ID | 238 | ||
| Auditor Location | Boston, Massachusetts | ||
| Auditor Opinion | Opinions on the Financial Statements and Internal Control over Financial Reporting We have audited the accompanying consolidated balance sheets of Allegro MicroSystems, Inc. and its subsidiaries (the “Company”) as of March 27, 2026 and March 28, 2025, and the related consolidated statements of operations, of comprehensive (loss) income, of changes in stockholders’ equity and of cash flows for each of the three years in the period ended March 27, 2026, including the related notes (collectively referred to as the “consolidated financial statements”). We also have audited the Company’s internal control over financial reporting as of March 27, 2026, based on criteria established in Internal Control - Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission (COSO). In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of March 27, 2026 and March 28, 2025, and the results of its operations and its cash flows for each of the three years in the period ended March 27, 2026 in conformity with accounting principles generally accepted in the United States of America. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of March 27, 2026, based on criteria established in Internal Control - Integrated Framework (2013) issued by the COSO. |