Leases - ASC 842 Quantitative Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2020	Apr. 30, 2019
Lessee, Lease, Description [Line Items]
Operating lease cost	$ 1,440	$ 1,380
Short-term lease cost	36	54
Short-term sublease income	(10)	(10)
Variable lease cost	455	448
Total lease cost	1,921	1,872
Cash paid for amounts included in the measurement of lease liabilities	662	1,291
Right-of-use assets obtained in exchange for new lease liabilities	$ 270	$ 394
Weighted-average remaining lease term (years)	4 years 8 months 23 days	5 years 8 months 13 days
Weighted-average discount rate	6.40%	6.40%
Immaterial Correction to Variable Lease Cost [Member]
Lessee, Lease, Description [Line Items]
Variable lease cost		$ 448