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Cover Page - USD ($)
12 Months Ended
Mar. 29, 2024
Mar. 31, 2023
May 20, 2024
Sep. 29, 2023
Cover [Abstract]        
Document Type 10-K      
Document Annual Report true      
Document Period End Date Mar. 29, 2024      
Current Fiscal Year End Date --03-29      
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       $ 2,567,653,518
Entity Common Stock, Shares Outstanding (in shares)     193,748,130  
Documents Incorporated by Reference

Portions of the registrant’s proxy statement for its 2024 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 29, 2024 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 2024      
Document Fiscal Period Focus FY      
Document Financial Statement Error Correction [Flag] true      
Document Financial Statement Restatement Recovery Analysis [Flag] true      
Auditor Name PricewaterhouseCoopers LLP Grant Thornton LLP    
Auditor Firm ID 238 248    
Auditor Location Boston, Massachusetts Boston, Massachusetts