Income Taxes - Schedule of Reconciliation of The Federal Statutory Income Tax Rate And The Provision For Income Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Income Tax Disclosure [Abstract]
Tax benefit at federal statutory rate	$ (50,772)	$ (51,297)	$ (68,767)
State taxes, net of federal benefit	(7,803)	(7,778)	(8,799)
Foreign rate difference	7,988	7,363	6,744
Nondeductible expenses	689	594	429
Research and development credit	(3,967)	(3,607)	(3,533)
Stock-based compensation	(4,148)	6,451	6,214
Change in reserve for unrecognized tax benefits	3,537	3,634	3,562
Other	(383)	97	61
Change in valuation allowance, including the effect of tax rate change	(34,119)	45,457	64,779
Effect of tax rate change on deferred tax assets	89,693
Provision for income taxes	$ 715	$ 914	$ 690