Revenue, Deferred Revenue and Commissions - Summary of Impact of Adopting Topic 606 on Condensed Consolidated Statement of Balance Sheet (Details) - USD ($) $ in Thousands	Oct. 31, 2018	Jan. 31, 2018
Disaggregation Of Revenue [Line Items]
Accounts receivable, net	$ 2,880	$ 2,858
Other current assets	3,830	4,397
Other assets	2,967	336
Accrued expenses	17,471	14,777
Deferred revenue	15,098	15,556
Accumulated deficit	(102,306)	$ (90,931)
Effect of Change | Topic 606
Disaggregation Of Revenue [Line Items]
Accounts receivable, net	840
Other current assets	491
Other assets	(2,688)
Accrued expenses	(162)
Deferred revenue	1,695
Accumulated deficit	(2,890)
Balances Without Adoption of Topic 606 | Topic 606
Disaggregation Of Revenue [Line Items]
Accounts receivable, net	3,720
Other current assets	4,321
Other assets	279
Accrued expenses	17,309
Deferred revenue	16,793
Accumulated deficit	$ (105,196)