Earnings (Loss) Per Share (Schedule Of Earnings (Loss) Per Share) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 31, 2013	Oct. 31, 2012	Oct. 31, 2013	Oct. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net income (loss)	$ (210)	$ 252	$ (843)	$ 409
Dividends paid and payable on preferred stock		(101)	(66)	(202)
Net income (loss) available to common stockholders	$ (210)	$ 151	$ (909)	$ 207
Weighted-average shares of common stock outstanding, basic	16,384,000	14,718,000	15,841,000	14,718,000
Effect of dilutive securities		11,000		5,000
Weighted-average shares of common stock outstanding, diluted	16,384,000	14,729,000	15,841,000	14,723,000
Basic	$ (0.01)	$ 0.01	$ (0.06)	$ 0.01
Diluted	$ (0.01)	$ 0.01	$ (0.06)	$ 0.01
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities that are not included in the diluted net loss calculation	1,520,902	2,629,497	1,520,902	2,724,519
Warrant [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities that are not included in the diluted net loss calculation	909,042	909,042	909,042	909,042
Preferred Stock [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive securities that are not included in the diluted net loss calculation		1,666,667		1,666,667