CONSOLIDATED STATEMENTS OF REDEEMABLE CONVERTIBLE PREFERENCE SHARES AND SHAREHOLDERS' EQUITY (DEFICIT) (USD $) In Thousands, except Share data	Total	Redeemable Convertible Preference Shares [Member]	Outstanding Ordinary Shares [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]
Beginning Balance, Amount at Jan. 31, 2010	$ (17,433)	$ 39,273	$ 3	$ 4,093	$ (21,529)
Beginning Balance, Shares at Jan. 31, 2010		12,268,131	7,744,461
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Shares	100,779		100,779
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Amount	140			140
Vesting of early exercised stock options	404			404
Stock-based compensation expense related to stock awards granted to employees and consultants	1,856			1,856
Net income	13,929				13,929
Ending Balance, Amount at Jan. 31, 2011	(1,104)	39,273	3	6,493	(7,600)
Ending Balance, Shares at Jan. 31, 2011		12,268,131	7,845,240
Issuance of preference shares, Shares		1,047,596
Issuance of preference shares, Amount		11,627
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Shares	454,053		454,053
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Amount	824			824
Vesting of early exercised stock options	394			394
Stock-based compensation expense related to stock awards granted to employees and consultants	3,616			3,616
Net excess income tax benefit associated with stock-based compensation	125			125
Repurchase of ordinary shares			(698,424)
Repurchase of ordinary shares, Amount	(7,227)			(7,227)
Net income	9,821				9,821
Ending Balance, Amount at Jan. 31, 2012	6,449	50,900	3	4,225	2,221
Ending Balance, Shares at Jan. 31, 2012		13,315,727	7,600,869
Conversion of redeemable convertible preference shares to ordinary shares		(13,315,727)	13,315,727
Conversion of redeemable convertible preference shares to ordinary shares, Amount	50,900	(50,900)	6	50,894
Issuance of shares in connection with initial public offering, net of issuance cost, Shares			5,804,651
Issuance of shares in connection with initial public offering, net of issuance cost, Amount	30,415		3	30,412
Conversion of preference share warrants to ordinary share warrants	110			110
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Shares	313,827		313,827
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Amount	950			950
Vesting of early exercised stock options	314			314
Stock-based compensation expense related to stock awards granted to employees and consultants	4,999			4,999
Net excess income tax benefit associated with stock-based compensation	7			7
Net income	18,188				18,188
Ending Balance, Amount at Jan. 31, 2013	$ 112,332		$ 12	$ 91,911	$ 20,409
Ending Balance, Shares at Jan. 31, 2013			27,035,074