Income taxes Components of income tax expense (benefit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2016	Jan. 31, 2015
Components of income tax expense (benefit) [Abstract]
Current federal tax expense	$ 12	$ 49
Current foreign tax expense	1,541	1,851
State and other	71	(80)
Current income tax expense (benefit)	1,624	1,820
Deferred federal income tax (benefit) expense	0	0
Deferred foreign income tax (benefit) expense	(249)	1,231
State and other	0	0
Deferred tax (benefit) expense	(249)	1,231
Income tax expense	$ 1,375	$ 3,051