Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 31, 2018	Jan. 31, 2017
Deferred tax assets:
Net operating loss carryforwards	$ 127,621	$ 173,942
Tax credit carryover	33,105	15,319
Accruals and reserves	1,809	3,112
Deferred revenue	46,570	53,424
Stock-based compensation expense	24,133	26,401
Depreciation and amortization	15,367	7,302
Charitable contribution carryforwards	2,892	4,345
Other	465	0
Total deferred tax assets	251,962	283,845
Valuation allowance	(240,519)	(271,779)
Total deferred tax assets, net of valuation allowance	11,443	12,066
Deferred tax liabilities:
Deferred commissions	(10,383)	(11,222)
Total deferred tax liabilities	(10,383)	(11,222)
Net deferred tax assets, net of valuation allowance	$ 1,060	$ 844