Loss Per Share (Schedule Of Earnings (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jul. 31, 2015	Jul. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net loss	$ (696)	$ (247)
Dividends paid and payable on preferred stock
Net loss available to common stockholders	$ (696)	$ (247)
Weighted-average shares of common stock outstanding, basic	16,389	16,384
Effect of dilutive securities
Weighted-average shares of common stock outstanding, diluted	16,389	16,384
Basic	$ (0.04)	$ (0.02)
Diluted	$ (0.04)	$ (0.02)
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of antidilutive securities	1,663	1,091
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Number of antidilutive securities	719	719