Leases - ASC 842 Quantitative Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Leases [Abstract]
Operating lease cost	$ 1,431	$ 1,365	$ 4,343	$ 4,065
Short-term lease cost	55	115	214	251
Short-term sublease income	(10)	(30)	(30)	(60)
Variable lease cost	(18)	340	352	849
Total lease cost	$ 1,458	$ 1,790	4,879	5,105
Cash paid for amounts included in the measurement of lease liabilities			3,697	3,976
Right-of-use assets obtained in exchange for new lease liabilities			$ 587	$ 1,420
Weighted-average remaining lease term (years)	4 years 3 months 18 days	5 years 2 months 12 days	4 years 3 months 18 days	5 years 2 months 12 days
Weighted-average discount rate	6.40%	6.37%	6.40%	6.37%