Income taxes Income tax narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Jan. 31, 2017	Jan. 31, 2016
Components of deferred income tax assets [Line Items]
Repatriation	$ 1,338	$ 821
Deferred Tax Liability Not Recognized, Determination of Deferred Tax Liability is Not Practicable, Undistributed Earnings of Foreign Subsidiaries	Determination of the amount of unrecognized deferred income tax liabilities on these earnings is not practicable, because such liability, if any, is dependent on circumstances existing if and when remittance occurs.
Suspended excess tax (benefit) expense from stock options exercised	$ 300
State NOL carryforward	1,877	1,419
Federal operating loss carryforward, gross	$ 28,400
Federal operating loss carryforward expires	Jan. 31, 2031
Operating Loss Carryforwards, expiration dates	expire at various times from 2017 to 2031
Foreign tax credit	$ 4,695	2,861
Valuation Allowance, Methodologies and Assumptions	The Company continues to have a valuation allowance on its domestic DTAs since domestic losses continue to be generated.
Tax Credit Carryforward, Expiration Date	Jan. 31, 2022
Undistributed earnings of foreign subsidiaries	$ 36,600
Income Tax Examination, Description	No changes were made to the reported tax
Open Tax Year	2014
Open tax years up to the amount of research tax credit generated	January 31, 2002 through January 31, 2009
India
Components of deferred income tax assets [Line Items]
Repatriation	$ 100	200
Foreign Earnings Repatriated	500	$ 2,800
Middle East [Member]
Components of deferred income tax assets [Line Items]
Foreign tax credit	$ 100