Net Loss per Share - Schedule of Computation of Net (Loss) Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
Jun. 27, 2025	Jun. 28, 2024
Earnings Per Share [Abstract]
Net loss attributable to Allegro MicroSystems, Inc.	$ (13,227)	$ (17,675)
Basic weighted average common shares (in shares)	184,587,027	193,465,708
Dilutive effect of common stock equivalents (in shares)	0	0
Diluted weighted average common shares (in shares)	184,587,027	193,465,708
Basic net loss per common share attributable to Allegro MicroSystems, Inc. stockholders	$ (0.07)	$ (0.09)
Diluted net loss per common share attributable to Allegro MicroSystems, Inc. stockholders	$ (0.07)	$ (0.09)

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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+ Details