Capital Stock - Additional Information (Detail) - USD ($)				3 Months Ended
	May 29, 2020	Mar. 16, 2020	May 29, 2019	Apr. 30, 2021	Apr. 30, 2020	Jan. 31, 2021
Class Of Stock [Line Items]
Preference shares, shares authorized				20,000,000		20,000,000
Preference shares, par value				$ 0.00045		$ 0.00045
Preference shares, shares issued				0		0
Preference shares, shares outstanding				0		0
Ordinary shares, shares authorized				200,000,000		200,000,000
Stock repurchased during period, cash				$ 0	$ 1,000,000
2012 Equity Incentive Plan [Member]
Class Of Stock [Line Items]
Additional ordinary shares reserved for issuance				1,599,634
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				444,343
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%
Stock Repurchase Program $50.0 Million Authorization [Member]
Class Of Stock [Line Items]
Stock repurchase program, authorization date			May 29, 2019
Stock repurchase program, expiration date			Jun. 30, 2020
Stock repurchased, shares		25,719		0
Stock repurchased during period, cash		$ 1,000,000.0
Stock repurchase program, extended expiration period	12 months
Stock repurchase program, extended expiration date	Jun. 30, 2021
Amount available under stock repurchase program				$ 49,000,000.0
Stock Repurchase Program $50.0 Million Authorization [Member] | Maximum [Member]
Class Of Stock [Line Items]
Amount authorized under stock repurchase program			$ 50,000,000.0