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.

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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.

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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)
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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.

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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

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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.

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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.

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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, 2019	Apr. 30, 2018	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Accrued share based compensation expense			$ 5.8
Closing price of stock			$ 59.14
2012 Equity Incentive Plan [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	1,453,659	1,507,032
2012 Equity Incentive Plan [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%
Amended and Restated 2012 Employee Stock Purchase Plan [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	403,794	418,620
Amended and Restated 2012 Employee Stock Purchase Plan [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			$ 3.9
Weighted average recognition period			2 years 5 months 26 days
Stock options [Member] \| 2012 Equity Incentive Plan [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			$ 52.1	$ 42.9	$ 52.1
Restricted Stock and Restricted Stock Units [Member] \| 2012 Equity Incentive Plan [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 5 months 26 days
Total unrecognized compensation cost, restricted stock units			$ 113.8
Accrued share based compensation expense			5.8
Aggregate intrinsic value of unvested restricted stock units			$ 154.8