Stock-based compensation Stock-based compensation expense (Details) (USD $)	3 Months Ended		9 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Stock-based compensation expense [Abstract]
Stock-based compensation expense	$ 27,000	$ 106,000	$ 95,000	$ 366,000
unrecognized compensation expense	$ 1,000,000		$ 1,000,000
expense expected to be recognized over a period			2 years 6 months 20 days