Leases - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Oct. 31, 2020	Oct. 31, 2019	Oct. 31, 2020	Oct. 31, 2019
Leases [Abstract]
Operating lease expense	$ 0.8	$ 0.7	$ 2.2	$ 2.2
Weighted-average remaining lease term - operating leases	4 years 4 months 28 days		4 years 4 months 28 days
Weighted-average discount rate - operating leases	4.43%		4.43%