Cover
Sep. 21, 2023
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Sep. 21, 2023
Entity File Number 001-39675
Entity Registrant Name Allegro MicroSystems, Inc.
Entity Central Index Key 0000866291
Entity Tax Identification Number 46-2405937
Entity Incorporation, State or Country Code DE
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
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common Stock, par value $0.01 per share
Entity Emerging Growth Company false
Trading Symbol ALGM
Security Exchange Name NASDAQ