Related party transactions - Summary of Related Party Transaction (Parenthetical) (Detail) - Shanghai Guangcheng Information [Member] ¥ in Millions, $ in Millions	12 Months Ended
Mar. 31, 2022 USD ($)	Mar. 31, 2022 CNY (¥)	Apr. 01, 2021 USD ($)
Related Party Transaction [Line Items]
Debt Instrument, Face Amount			$ 5.0
Debt Instrument, Interest Rate, Stated Percentage	3.50%	3.50%
Loan amount obtained from related party	$ 1.5	¥ 10.0

Face (par) amount of debt instrument at time of issuance.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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The cash inflow from a long-term borrowing made from related parties where one party can exercise control or significant influence over another party; including affiliates, owners or officers and their immediate families, pension trusts, and so forth. Alternate caption: Proceeds from Advances from Affiliates.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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