Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jul. 31, 2016	Apr. 30, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015	Jan. 31, 2016
New Accounting Pronouncement, Early Adoption [Line Items]
Restricted cash	$ 12,732			$ 12,732		$ 7,132
Deferred commissions, current	14,023			14,023		15,703
Deferred income taxes, non-current	14,100			14,100		14,300
Sales commission expenses	19,600		$ 9,700	37,200	$ 18,600
Decrease in provision for income taxes	106		57	526	214
Accumulated deficit	(680,752)			(680,752)		$ (555,335)
Total stock-based compensation expense	$ 27,896		$ 11,800	50,894	$ 20,659
Accounting Standards Update 2016-09, Forfeiture Rate Component | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Decrease in provision for income taxes		$ (535)		535
Total stock-based compensation expense		864		$ 864
Accounting Standards Update 2016-09, Forfeiture Rate Component | Accumulated Deficit | New Accounting Pronouncement, Early Adoption, Effect
New Accounting Pronouncement, Early Adoption [Line Items]
Cumulative-effect adjustment, new accounting standard		$ 2,100