Warranty (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jan. 31, 2013	Jan. 31, 2012
Warranty claim activity
Beginning accrued warranty balance	$ 1,400	$ 2,300
Provision	630	700
Provision for prior year	(490)	(764)
Costs incurred	(540)	(836)
Ending accrued warranty balance	$ 1,000	$ 1,400
Minimum [Member]
Warranty [Line Items]
Product warranty period	5 years
Maximum [Member]
Warranty [Line Items]
Product warranty period	10 years