Leases - Additional Information (Detail) $ in Millions	3 Months Ended	6 Months Ended
	Jul. 31, 2019 USD ($)	Jul. 31, 2019 USD ($)
Leases [Abstract]
Lease, year of expiration		The leases expire at various dates through fiscal year 2028
Operating leases, existence of options to extend		true
Operating leases, options to extend description		some of which include options to extend the lease for up to 3 years.
Operating leases, extended term	3 years	3 years
Operating lease expense	$ 0.7	$ 1.5
Weighted-average remaining lease term – operating leases	4 years 1 month 24 days	4 years 1 month 24 days
Weighted-average discount rate – operating leases	5.00%	5.00%