Consolidated Statements of Redeemable Convertible Preference Shares and Shareholders' Equity (Deficit) (USD $) In Thousands, except Share data	Total	Outstanding Ordinary Shares [Member]	Additional Paid-in Capital [Member]	Retained Earnings (Accumulated Deficit) [Member]	Redeemable Convertible Preference Shares [Member]
Beginning Balance, Amount at Jan. 31, 2011	$ (1,104)	$ 3	$ 6,493	$ (7,600)	$ 39,273
Beginning Balance, Shares at Jan. 31, 2011		7,845,240			12,268,131
Issuance of preference shares, Amount					11,627
Issuance of preference shares, Shares					1,047,596
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Amount	824		824
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Shares	454,053	454,053
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, Amount	(7,227)		(7,227)
Repurchase of ordinary shares, Shares		(698,424)
Net income	9,821			9,821
Ending Balance, Amount at Jan. 31, 2012	6,449	3	4,225	2,221	50,900
Ending Balance, Shares at Jan. 31, 2012		7,600,869			13,315,727
Conversion of redeemable convertible preference shares to ordinary shares, Amount	50,900	6	50,894		(50,900)
Conversion of redeemable convertible preference shares to ordinary shares, Shares		13,315,727			(13,315,727)
Issuance of shares in connection with initial public offering, net of issuance cost, Amount	30,415	3	30,412
Issuance of shares in connection with initial public offering, net of issuance cost, Shares		5,804,651
Conversion of preference share warrants to ordinary share warrants	110		110
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Amount	950		950
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Shares	313,827	313,827
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	27,035,074
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Amount	6,920	1	6,919
Exercise of stock options, dollar amounts net of unvested stock options exercised early, Shares	1,160,286	1,160,286
Vesting of early exercised stock options	143		143
Vesting of restricted stock units
Vesting of restricted stock units, shares		174,888
Employee stock purchase plan, Amount	1,744		1,744
Employee stock purchase plan, Shares		341,973
Exercise of warrants to purchase ordinary shares, Amount	130		130
Exercise of warrants to purchase ordinary shares, shares		36,292
Stock-based compensation expense related to stock awards granted to employees and consultants	8,535		8,535
Net excess income tax benefit associated with stock-based compensation	903		903
Net income	25,654			25,654
Ending Balance, Amount at Jan. 31, 2014	$ 156,361	$ 13	$ 110,285	$ 46,063
Ending Balance, Shares at Jan. 31, 2014	28,748,513	28,748,513