Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Oct. 31, 2016	Oct. 31, 2015	Oct. 31, 2016	Oct. 31, 2015
Warranty claim activity
Beginning balance	$ 1,000	$ 1,000	$ 1,000	$ 950
Provision	155	89	331	332
Costs incurred	(155)	(89)	(331)	(282)
Ending balance	$ 1,000	$ 1,000	$ 1,000	$ 1,000
Minimum [Member]
Warranty [Line Items]
Product warranty period			5 years
Maximum [Member]
Warranty [Line Items]
Product warranty period			10 years