Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Thousands	12 Months Ended
	Mar. 28, 2025	Mar. 29, 2024	Mar. 31, 2023
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (72,763)	$ 152,888	$ 187,494
Net income attributable to non-controlling interests	247	191	137
Net (loss) income attributable to Allegro MicroSystems, Inc.	(73,010)	152,697	187,357
Other comprehensive (loss) income:
Foreign currency translation adjustment	(2,127)	(7,720)	(2,892)
Net actuarial gain (loss) on amortization of net transition obligation and prior service costs related to defined benefit plans, net of tax of $(84), $145 and $(164) in fiscal years 2025, 2024 and 2023, respectively	252	(434)	492
Comprehensive (loss) income	(74,885)	144,543	184,957
Other comprehensive (loss) gain attributable to non-controlling interests	(36)	97	64
Comprehensive (loss) income attributable to Allegro MicroSystems, Inc.	$ (74,921)	$ 144,640	$ 185,021