Correction of immaterial errors Adjustments to the previously reported statement of stockholders' equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss	$ (4,409)	$ (181)
Retained earnings	20,193	24,602	$ 24,783
Comprehensive loss	(3,859)	(3,551)
Total stockholders' equity	$ 69,028	72,800	75,839
Restatement Adjustment [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss		75
Retained earnings		(723)	(797)
Comprehensive loss		75
Total stockholders' equity		(723)	(797)
Scenario, Previously Reported [Member]
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net loss		(256)
Retained earnings		25,325	25,580
Comprehensive loss		(3,626)
Total stockholders' equity		$ 73,523	$ 76,636