Income taxes Components of income tax expense (benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Components of income tax expense (benefit) [Abstract]
Current federal tax (benefit) expense	$ (106)	$ 12
Current foreign tax (benefit) expense	837	1,541
Current state and other tax (benefit) expense	(1,309)	71
Subtotal	(578)	1,624
Deferred federal income tax (benefit) expense	0	0
Deferred foreign income tax (benefit) expense	(33)	(249)
Deferred state and other income tax (benefit) expense	0	0
Subtotal	(33)	(249)
Total	$ (611)	$ 1,375