Capital Stock - Additional Information (Detail) - USD ($)				3 Months Ended	9 Months Ended
	Nov. 29, 2016	May 31, 2016	Feb. 01, 2016	Oct. 31, 2016	Oct. 31, 2016	Oct. 31, 2015	Jan. 31, 2016
Class Of Stock [Line Items]
Preference shares, shares authorized				20,000,000	20,000,000		20,000,000
Preference shares, par value				$ 0.00045	$ 0.00045		$ 0.00045
Preference shares, shares issued				0	0		0
Preference shares, shares outstanding				0	0		0
Ordinary shares, shares authorized				200,000,000	200,000,000		200,000,000
Stock repurchase program, period		6 months
Stock repurchased during period, shares				0	405,089
Stock repurchased during period, cash					$ 20,183,000	$ 0
Maximum [Member]
Class Of Stock [Line Items]
Amount authorized under stock repurchase program		$ 75,000,000
Subsequent Event [Member]
Class Of Stock [Line Items]
Stock repurchase program, expiration date	Jun. 30, 2017
2012 Equity Incentive Plan [Member]
Class Of Stock [Line Items]
Additional ordinary shares reserved for issuance			1,455,001
2012 Equity Incentive Plan [Member] | Scenario, plan automatically increased by the lessor of [Member]
Class Of Stock [Line Items]
Annual increase in ordinary shares for available for future issuance			3,500,000
Annual shares increase for future issuance by percentage under 2012 equity incentive plan			4.50%
Amended and Restated 2012 Employee Stock Purchase Plan [Member]
Class Of Stock [Line Items]
Additional ordinary shares reserved for issuance			404,166
Amended and Restated 2012 Employee Stock Purchase Plan [Member] | Scenario, plan automatically increased by the lessor of [Member]
Class Of Stock [Line Items]
Annual increase in ordinary shares for available for future issuance			1,500,000
Annual shares increase for future issuance by percentage under 2012 employee stock purchase plan			1.25%