Statement Of Stockholders Equity (USD $) In Thousands, except Share data	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Total
Stockholders' Equity Attributable to Parent, Beginning Balance at Apr. 30, 2010		$ 10	$ 79,919	$ 383	$ (60,870)	$ 19,442
Shares, Outstanding, Beginning Balance at Apr. 30, 2010		10,476,633
Net loss					(16,665)	(16,665)
Translation adjustments				60		60
Total comprehensive income (loss)						(16,605)
Issuance of common stock, value		2	7,956			7,958
Issuance of common stock, shares		2,307,363
Exercise of stock options, value		1	2			3
Exercise of stock options, shares		1,000				16,000
Conversion of warrants and debt to stock, amount		2	6,274			6,276
Conversion of warrants and debt to stock, shares		1,793,281
Stock-based compensation			960			960
Stockholders' Equity Attributable to Parent, Ending Balance at Apr. 30, 2011		15	95,111	443	(77,535)	18,034
Shares, Outstanding, Ending Balance at Apr. 30, 2011		14,578,277
Net loss					(16,662)	(16,662)
Translation adjustments				(102)		(102)
Total comprehensive income (loss)						(16,764)
Issuance of common stock, value	2		3,970			3,972
Issuance of common stock, shares	1,666,667
Exercise of stock options, value			192			192
Exercise of stock options, shares		139,500				124,500
Preferred stock dividends			(334)			(334)
Stock-based compensation			921			921
Stockholders' Equity Attributable to Parent, Ending Balance at Apr. 30, 2012	2	15	99,860	341	(94,197)	6,021
Shares, Outstanding, Ending Balance at Apr. 30, 2012	1,666,667	14,717,777
Net loss					532	532
Translation adjustments				(61)		(61)
Total comprehensive income (loss)						471
Preferred stock dividends			(400)			(400)
Stock-based compensation			593			593
Stockholders' Equity Attributable to Parent, Ending Balance at Apr. 30, 2013	$ 2	$ 15	$ 100,053	$ 280	$ (93,666)	$ 6,684
Shares, Outstanding, Ending Balance at Apr. 30, 2013	1,666,667	14,717,777