Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 31, 2017	Jan. 31, 2016
Deferred tax assets:
Net operating loss carryforwards	$ 173,942	$ 137,456
Tax credit carryover	15,319	12,406
Accruals and reserves	3,112	1,921
Deferred revenue	53,424	20,314
Stock-based compensation expense	26,401	12,588
Depreciation and amortization	7,302	3,397
Charitable contribution carryforwards	4,345	4,380
Total deferred tax assets	283,845	192,462
Valuation allowance	(271,779)	(180,926)
Total deferred tax assets, net of valuation allowance	12,066	11,536
Deferred tax liabilities:
Deferred commissions	(11,222)	(11,000)
Total deferred tax liabilities	(11,222)	(11,000)
Net deferred tax assets, net of valuation allowance	$ 844	$ 536