Organization and Summary of Significant Accounting Policies - Additional Information (Detail) $ in Millions	3 Months Ended
Apr. 30, 2025 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Letter of credit	$ 0.4
Letter of credit irrevocable term	1 year

A document typically issued by a financial institution which acts as a guarantee of payment to a beneficiary, or as the source of payment for a specific transaction.

No definition available.

Name:	amba_LetterOfCredit
Namespace Prefix:	amba_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration