Common Stock and Stockholders' Equity - Summary of Activity Related to RSUs (Details) - 2016 Equity Incentive Plan - Restricted Stock Units (RSUs)	9 Months Ended
Oct. 31, 2019 $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of RSUs Outstanding, Awarded and unvested, Beginning balance \| shares	2,792,117
Number of RSUs Outstanding, Awards granted \| shares	1,361,518
Number of RSUs Outstanding, Awards vested \| shares	(840,059)
Number of RSUs Outstanding, Awards forfeited \| shares	(216,232)
Number of RSUs Outstanding, Awarded and unvested, Ending balance \| shares	3,097,344
Weighted-Average Grant Date Fair Value, Awarded and unvested, Beginning balance \| $ / shares	$ 42.62
Weighted-Average Grant Date Fair Value, Awards granted \| $ / shares	100.81
Weighted-Average Grant Date Fair Value, Awards vested \| $ / shares	46.93
Weighted-Average Grant Date Fair Value, Awards forfeited \| $ / shares	60.75
Weighted-Average Grant Date Fair Value, Awarded and unvested, Ending balance \| $ / shares	$ 65.77

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

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)(iv)(3)
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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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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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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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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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No definition available.

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