Significant accounting policies Correction of immaterial errors (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended		60 Months Ended
	Jan. 31, 2013	Jan. 31, 2012	Jan. 31, 2011
Net Income (Loss) Attributable to Parent	$ (18,485)	$ (4,959)
Loss from operations		(5,063)
Inventories, net	42,333	40,204
Total current assets	84,346	82,670
Total assets	149,479	157,283
Total stockholders' equity	54,255	72,355	78,262
Total liabilities and stockholders' equity	149,479	157,283
Cost of sales	173,911	197,175
Inventories	2,080	4,683
Restatement of Prior Year Income, Net of Tax		28	208
Retained Earnings, Unappropriated	4,553	23,038
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	(18,630)	(6,732)
Scenario, Previously Reported [Member]
Net Income (Loss) Attributable to Parent		(4,987)
Loss from operations		(5,091)
Inventories, net		39,968
Total current assets		82,434
Total assets		157,047
Total stockholders' equity		72,119
Total liabilities and stockholders' equity		157,047
Cost of sales		197,203
Inventories		(4,655)
Retained Earnings, Unappropriated		22,802
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		(6,760)
Restatement Adjustment [Member]
Net Income (Loss) Attributable to Parent		28
Loss from operations		28
Inventories, net		236
Total current assets		236
Total assets		236
Total stockholders' equity		236
Total liabilities and stockholders' equity		236
Cost of sales		(28)
Inventories		(28)
Retained Earnings, Unappropriated		236
Comprehensive Income (Loss), Net of Tax, Attributable to Parent		$ 28