Net Earnings (Loss) Per Share (Schedule Of Earnings Per Share, Basic And Diluted) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2012	Oct. 31, 2011	Oct. 31, 2012	Oct. 31, 2011
Earnings (Net Loss) Per Share [Abstract]
Net income (loss)	$ 1,950	$ (2,976)	$ 2,511	$ (5,692)
Denominator for basic net earnings (loss) per common share-weighted average shares	14,498,269	14,330,954	14,456,938	14,315,318
Stock options and restricted stock units	180,000	0	170,000	0
Denominator for diluted net earnings (loss) per common share - weighted average shares and assumed conversions	14,677,640	14,330,954	14,626,899	14,315,318
Basic	$ 0.13	$ (0.21)	$ 0.17	$ (0.40)
Diluted	$ 0.13	$ (0.21)	$ 0.17	$ (0.40)