The Company And Summary Of Significant Accounting Policies (Summary Of Fair Value Assumptions) (Details) (USD $)	12 Months Ended
Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Stock Compensation Information [Abstract]
Expected term (in years)	4 years	4 years	4 years
Risk-free interest rate	0.50%	1.10%	1.30%
Volatility	77.00%	89.00%	84.00%
Weighted-average fair value of stock options granted during the year	$ 1.01	$ 2.38	$ 3.38

The range of expected volatilities used and the weighted-average expected volatility for an entity using a valuation technique with different volatilities during the contractual term.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (f)(2)(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph e(2)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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