Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2019	Jul. 31, 2018	Jul. 31, 2019	Jul. 31, 2018
Warranty claim activity
Beginning balance	$ 700	$ 925	$ 700	$ 925
Provision	245	86	316	141
Costs incurred	(145)	(86)	(216)	(141)
Ending balance	$ 800	$ 925	$ 800	$ 925
Maximum [Member]
Warranty [Line Items]
Product warranty period			10 years