Leases - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2018	Jan. 31, 2017	Jan. 31, 2016
Maximum
Property, Plant and Equipment [Line Items]
Operating leases, non-cancelable term	1 year
Foreign Country
Property, Plant and Equipment [Line Items]
Office rental expense	$ 1,200	$ 1,200	$ 1,200
Seismic Equipment Lease Pool | Domestic Tax Authority
Property, Plant and Equipment [Line Items]
Lease expense incurred by the Company	$ 774	$ 552	$ 831