Income Taxes Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Jan. 31, 2020	Jan. 31, 2019	Jan. 31, 2018
Deferred tax assets:
Net operating loss carryforwards	$ 102,064	$ 76,259
Stock-based compensation	9,285	7,710
Allowance for doubtful accounts	255	65
Operating lease liability	29,280	758
Accrued expenses	1,974	2,081
Unearned revenue	26	26
Property and equipment	730	414
Intangible assets	0	712
Other	208	133
Total deferred tax assets	143,822	88,158
Less: valuation allowance	(105,277)	(80,901)	$ (43,100)
Deferred tax assets, net of valuation allowance	38,545	7,257
Deferred tax liabilities:
Prepaid expenses	0	(57)
Operating lease right-of-use assets	(26,518)	0
Intangible assets	(1,479)	0
Costs to obtain revenue contracts	(9,767)	(6,966)
Other	(686)	(231)
Total deferred tax liabilities	(38,450)	(7,254)
Net deferred tax asset (liability)	$ 95	$ 3