Income taxes Income tax disclosure (Details) (USD $)	12 Months Ended
	Jan. 31, 2014	Jan. 31, 2013
Components of deferred income tax assets
U.S. Federal NOL carryforward	$ 2,298,000	$ 3,680,000
Non-qualified deferred compensation	2,358,000	2,092,000
Research tax credit	1,965,000	1,964,000
Foreign NOL carryforward	1,004,000	612,000
Foreign tax credit	1,294,000	1,297,000
Stock compensation	1,162,000	1,417,000
Other accruals not yet deducted	581,000	1,086,000
State NOL carryforward	1,173,000	1,066,000
Accrued commissions and incentives	814,000	837,000
Accrued pension	182,000	428,000
Inventory valuation allowance	413,000	306,000
Other	217,000	94,000
Inventory uniform capitalization	102,000	132,000
Deferred tax assets, gross	13,563,000	15,011,000
Valuation allowance	(11,591,000)	(12,960,000)
Total deferred tax assets, net of valuation allowances	1,972,000	2,051,000
Components of the deferred income tax liability
Depreciation	963,000	1,040,000
Prepaid	231,000	340,000
Total deferred tax liabilities	1,194,000	1,380,000
Deferred income tax, net	778,000	671,000
Balance sheet classification
Deferred tax assets - long-term	1,667,000	1,358,000
Deferred tax liabilities - current	889,000	687,000
Excess tax (benefit) expense from stock options exercised		11,000
Tax benefit of stock options exercised	0	11,000
Valuation allowance domestic deferred tax assets		(13,900,000)
Federal operating loss carryforward, gross	9,100,000
Federal operating loss carryforward expires		Jan. 31, 2030
Operating Loss Carryforwards, Expiration Dates	expire at various times from 2014 to 2031
State NOL, subject to expiration	2,000
Tax Credit Carryforward, Expiration Date	Jan. 31, 2022
Undistributed earnings of foreign subsidiaries	22,000,000
Income Tax Examination, Description	IRS began an audit of the fiscal year ended January 31, 2012
Open Tax Year	2011
Open tax years up to the amount of research tax credit generated	January 31, 2002 through January 31, 2009
Additional Paid-in Capital
Balance sheet classification
Excess tax (benefit) expense from stock options exercised		11,000
Foreign Tax Authority [Member]
Components of deferred income tax assets
Foreign tax credit	500,000
Middle East [Member]
Components of deferred income tax assets
Foreign tax credit	500,000
Foreign Tax Authority [Member]
Balance sheet classification
Change in valuation allowance	$ (1,209,000)	$ 613,000