Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended
	Apr. 30, 2014	Apr. 30, 2013	Jan. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unvested shares subject to repurchase at an aggregate price	$ 400,000		$ 500,000
Weighted-average grant date fair value of options granted	$ 15.47	$ 2.38
Unrecognized compensation cost, net of estimated forfeitures, related to unvested stock options granted	40,000,000
Weighted average period of unvested stock options	5 years
Closing stock price	$ 19.21
Intrinsic value of options exercised	30,842,309
2013 Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock acquire at fair market value	85.00%
Common stock purchases through payroll deductions	15.00%
Shares purchased under ESPP	0
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value, RSUs Granted	$ 27.17
Unrecognized compensation cost, net of estimated forfeitures, related to unvested RSUs	$ 9,500,000
Weighted-average period related to unvested restricted stock unit	3 years 8 months 12 days
Unreleased Restricted Stock Units, RSUs Granted	183,775	0
Class A common stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares outstanding	38,301,754		15,044,750
Class B common stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares outstanding	89,271,904		109,746,795
Common stock, shares unvested	1,391,915		1,824,457