Income Taxes - Schedule of Provision for Income taxes differs from Federal Statutory Income Tax Rate to Income Before Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Income Tax Disclosure [Abstract]
U.S. federal taxes at statutory tax rate	$ (53,143)	$ (35,816)
State taxes, net of federal benefit	11	8
Nondeductible expenses	978	281
Nondeductible stock-based compensation	4,453	2,894
Foreign rate differential	(54)	(59)
Remeasurement of deferred tax assets and liabilities	59,160
Other	(1,859)	(618)
Change in valuation allowance	(9,068)	33,775
Provision for income taxes	$ 478	$ 465	$ 634