Stock options Unvested options (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013
percentage of options expect to vest	85.00%
unvested option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares	263	383
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 8.31	$ 6.91
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value	$ 1,633	$ 4
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Net of Forfeitures	103
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 10.55	$ 6.78
Vested options in the period	(184)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period	39
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price	$ 7.05