Stock options Options additional text (Details) (USD $) In Millions, except Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2015	Jan. 31, 2014
increase number of shares that may be issued	2.00%
Initial number of options to grant under plan	350,000
vesting period for stock options	P4Y
unrecognized stock option expense	$ 0.8
cost is expected to be recognized over the weighted-average period	2 years 4 months 24 days
Maturity period for stock option from issuance date	10 years
Stock Option [Member]
Weighted average fair value of options granted	$ 4.73	$ 4.78