Accrued share based compensation expense.

No definition available.

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- Definition

Number of additional shares reserved for issuance under an established employee stock purchase plan.

+ References

No definition available.

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- Definition

Annual increase in ordinary shares for available for future issuance.

+ References

No definition available.

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- Definition

Annual increase in shares for available for future issuance by percentage of outstanding ordinary shares as of last day of immediately preceding fiscal year.

+ References

No definition available.

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- Definition

Annual increase in shares for available for future issuance by percentage of the outstanding ordinary shares on the first day of such fiscal year.

+ References

No definition available.

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- Definition

Closing market price of stock on NASDAQ on last day of reporting period.

+ References

No definition available.

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- Definition

Ownership percentage of voting power.

+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (i)
-URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901

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- Definition

Amount of cost to be recognized for nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

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- Definition

Amount of cost to be recognized for option under share-based payment arrangement.

+ References

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- Definition

Description of service or performance condition required to be met for earning right to award under share-based payment arrangement. Includes, but is not limited to, combination of market, performance or service condition.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

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.

+ References

No definition available.

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- Definition

The highest percentage of annual salary that an employee is permitted to utilize with respect to the plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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- Definition

Number of additional shares authorized for issuance under share-based payment arrangement.

+ References

No definition available.

+ Details

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- Definition

Intrinsic value of nonvested award under share-based payment arrangement. Excludes share and unit options.

+ References

No definition available.

+ Details

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- Definition

Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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- Definition

Purchase price of common stock expressed as a percentage of its fair value.

+ References

No definition available.

+ Details

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Employee Benefits and Stock-based Compensation - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		12 Months Ended
	Apr. 30, 2020	Apr. 30, 2019	Jan. 31, 2021	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018	Jan. 29, 2021
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Accrued share based compensation expense			$ 4.4
Closing price of stock							$ 94.36
EIP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Voting power of all classes of company's shares			10.00%
Additional ordinary shares reserved for issuance	1,521,252	1,453,659
EIP [Member] \| Scenario, plan automatically increased by the lessor of [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in ordinary shares for available for future issuance	3,500,000	3,500,000
Annual shares increase for future issuance by percentage under 2012 equity incentive plan	4.50%	4.50%
ESPP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of ordinary shares, percentage			85.00%		85.00%	85.00%
Percentage of salary contribution by employees			15.00%
Additional ordinary shares reserved for issuance	422,570	403,794
ESPP [Member] \| Scenario, plan automatically increased by the lessor of [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Annual increase in ordinary shares for available for future issuance	1,500,000	1,500,000
Annual shares increase for future issuance by percentage under 2012 employee stock purchase plan	1.25%	1.25%
Stock options [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total unrecognized compensation cost, stock options			$ 3.1
Weighted average recognition period			2 years 4 months 24 days
Stock options [Member] \| EIP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Option's term of up to 10 years from grant date			10 years	10 years	10 years
Vesting schedule			vest 25% on the first anniversary service date of the grant and remainder vest ratably over the following 36 months.
Stock options [Member] \| Incentive stock options granted to 10% ownership [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of ordinary shares, percentage			110.00%
Stock options [Member] \| Non statutory stock options and incentive stock options granted to less than 10% ownership [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Purchase price of ordinary shares, percentage			100.00%
Restricted Stock and Restricted Stock Units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Total fair value of vesting dates of restricted stock and restricted stock units vested			$ 69.0	$ 52.1	$ 42.9
Restricted Stock and Restricted Stock Units [Member] \| EIP [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting schedule			1/4th of the shares on the first anniversary service date of the grant and 1/16th of the shares vest every 3 months thereafter, so as to be 100% vested on the fourth anniversary of the vesting commencement date
Restricted stock units [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Weighted average recognition period			2 years 4 months 6 days
Total unrecognized compensation cost, restricted stock units			$ 123.9
Aggregate intrinsic value of unvested restricted stock units			$ 271.0