Property and Equipment - Property and Equipment (Details) - USD ($) $ in Thousands	Oct. 31, 2017	Jan. 31, 2017
Property Plant And Equipment [Line Items]
Gross property and equipment	$ 18,149	$ 14,249
Less: accumulated depreciation and amortization	(12,940)	(9,607)
Total property and equipment, net	5,209	4,642
Furniture and equipment
Property Plant And Equipment [Line Items]
Gross property and equipment	1,660	1,415
Software development costs
Property Plant And Equipment [Line Items]
Gross property and equipment	15,843	12,376
Leasehold improvements
Property Plant And Equipment [Line Items]
Gross property and equipment	554	$ 458
Construction in progress
Property Plant And Equipment [Line Items]
Gross property and equipment	$ 92