Significant accounting policies Cash and cash equivalents (Details) - USD ($) $ in Thousands	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 16,631	$ 9,900	$ 13,395
United States
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	229
Middle East [Member]
Cash and Cash Equivalents [Line Items]
Cash and cash equivalents	$ 16,402