Stock-based compensation - Summary of RSU Activity (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Sep. 30, 2023
Restricted stock units
Number of Restricted Shares
Outstanding as of March 31, 2021 (in shares)	1,351,280
Granted (in shares)	1,216,516
Vested (in shares)	(297,019)
Cancelled (in shares)	(80,940)
Outstanding as of June 30, 2021 (in shares)	2,189,837
Weighted Average Grant Date Fair Value
Outstanding as of March 31, 2021 (in dollars per share)	$ 24.38
Granted (in dollars per share)	18.11
Vested (in dollars per share)	25.36
Cancelled (in dollars per share)	21.70
Outstanding as of June 30, 2021 (in dollars per share)	$ 20.86
Total unrecognized compensation cost	$ 39.4
Expenses expected to be recognized over a weighted average remaining period	3 years
Stock options
Weighted Average Grant Date Fair Value
Total unrecognized compensation cost	$ 46.4
Expenses expected to be recognized over a weighted average remaining period	2 years 8 months 12 days

Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 718
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-Section 50
-Paragraph 2
-Subparagraph (c)(2)(ii)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480429/718-10-50-2

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Per share or unit weighted-average fair value of nonvested award under share-based payment arrangement. Excludes share and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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