Capital Stock - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended		12 Months Ended
	Nov. 06, 2012	Oct. 15, 2012	Jan. 31, 2012	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011	Oct. 10, 2012
Class of Stock [Line Items]
Net proceeds from issuance of preference shares				$ 0	$ 11,627,000	$ 0
Redeemable convertible preference shares conversion		Converted into ordinary shares on a one-to-one basis
Repurchase of ordinary shares price per share			$ 10.35		$ 10.35
Number of ordinary shares repurchased			698,424		698,424
Cash paid for repurchase of ordinary shares			7,200,000	0	7,228,000	0
Effective date of split				Aug. 24, 2012
Reverse stock split				One (1) ordinary share for every four and one half (4.5) authorized, issued and outstanding ordinary shares and one (1) preference share for every four and one half (4.5) authorized, issued and outstanding preference shares (the "Stock Split").
Initial public offering of shares		6,000,000
Shares issued during period, shares sold by certain shareholders		1,095,349
Initial public offering price per share		$ 6.00
Proceeds from initial public offering		25,400,000
Redeemable convertible preference shares converted to ordinary shares		13,315,727
Over-allotment option shares sold	900,000
Net proceeds from the sale of over-allotment shares	5,000,000
Preference shares, shares authorized		20,000,000	0	20,000,000	0
Preference shares, par value		$ 0.00045	$ 0.00000	$ 0.00045	$ 0.00000
Preference shares, shares issued			0	0	0
Preference shares, shares outstanding			0	0	0
Company issued warrants to purchase Series B redeemable convertible preference shares at an exercise price			3.582	3.582	3.582	3.582
Fair value of the warrants			259,000		259,000
Aggregate fair market value							110,000
Total ordinary share warrants outstanding				36,292
Ordinary shares authorized			44,444,444	200,000,000	44,444,444
Series D Redeemable convertible preference shares [Member]
Class of Stock [Line Items]
Issuance of preference shares			1,047,596
Preference shares, price per share			$ 11.25		$ 11.25
Net proceeds from issuance of preference shares			$ 11,627,000
Redeemable convertible preference shares conversion			Converted into ordinary shares on a one-to-one basis.