Revenue from Contracts with Customers - Revenue Disaggregation (Detail) - USD ($) $ in Thousands	3 Months Ended
	Apr. 30, 2021	Apr. 30, 2020
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 4,194	$ 3,187
Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4,063	3,012
Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	131	175
Seamap | Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,913	2,014
Seamap | Revenue recognized over time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	131	175
Klein | Revenue recognized at a point in time
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 1,150	$ 998