Balance Sheet Components - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Oct. 31, 2015	Oct. 31, 2014	Oct. 31, 2015	Oct. 31, 2014	Jan. 31, 2015
Property Plant And Equipment [Line Items]
Accumulated depreciation of property and equipment acquired under capital lease	$ 1,300,000		$ 1,300,000		$ 140,000
Depreciation expense	8,500,000	$ 6,600,000	24,800,000	$ 17,400,000
Amount of interest capitalized to property and equipment	291,000	51,000	389,000	278,000
Servers
Property Plant And Equipment [Line Items]
Gross amount of property and equipment acquired under capital lease	7,900,000		7,900,000		1,900,000
Depreciation expense	517,000	$ 0	1,100,000	$ 0
Construction in progress
Property Plant And Equipment [Line Items]
Gross amount of property and equipment acquired under capital lease	$ 1,500,000		$ 1,500,000		$ 69,000