Income taxes Income taxes (Details) (USD $)	3 Months Ended	6 Months Ended
Jul. 31, 2012	Jul. 31, 2011	Jul. 31, 2012 Rate	Jul. 31, 2011 Rate
Operating loss carryforwards [Line Items]
Valuation allowance, deferred tax asset, change in amount	$ 165,000
effective income tax rate			(1.60%)	(46.40%)
Net operating loss used	3,300,000
Deferred tax assets credit carryforward-RD	800,000		800,000
tax expense associated with the repatriation of foreign earnings		1,800,000
repatriation of foreign earnings		3,100,000
Operating loss carryforwards	$ 8,000,000		$ 8,000,000

The total amount of dividends declared in the period for each class of stock and the contractual amount of dividends (or interest on participating income bonds) that must be paid for the period (for example, unpaid cumulative dividends). Dividends declared in the current period do not include dividends declared in respect of prior-period unpaid cumulative dividends. Preferred dividends that are cumulative only if earned are deducted only to the extent that they are earned.

+ References+ Details

A ratio calculated by dividing the reported amount of income tax expense attributable to continuing operations for the period by GAAP-basis pretax income from continuing operations.

+ References+ Details

- Definition

The amount of the change in the period in the valuation allowance for a specified deferred tax asset.

+ References+ Details