Earnings (Loss) Per Share (Computation Of Basic And Diluted Earnings (Net Loss) Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	12 Months Ended
Apr. 30, 2013	Jan. 31, 2013	Oct. 31, 2012	Jul. 31, 2012	Apr. 30, 2012	Jan. 31, 2012	Oct. 31, 2011	Jul. 31, 2011	Apr. 30, 2013	Apr. 30, 2012	Apr. 30, 2011
Earnings (Net Loss) Per Share [Abstract]
Net income (loss)	$ 5,190	$ 2,057	$ 1,950	$ 561	$ (5,980)	$ (9,114)	$ (2,976)	$ (2,716)	$ 9,758	$ (20,786)	$ (20,018)
Denominator for basic earnings (loss) per share - weighted-average shares									14,563	14,344	14,252
Stock options and restricted stock units									270	0	0
Denominator for diluted earnings (net) per common share - weighted average shares and assumed conversions									14,833	14,344	14,252
Basic	$ 0.36	$ 0.14	$ 0.13	$ 0.04	$ (0.42)	$ (0.63)	$ (0.21)	$ (0.19)	$ 0.67	$ (1.45)	$ (1.40)
Diluted	$ 0.35	$ 0.14	$ 0.13	$ 0.04	$ (0.42)	$ (0.63)	$ (0.21)	$ (0.19)	$ 0.66	$ (1.45)	$ (1.40)

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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+ Details

- Definition

The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References+ Details

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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-Glossary Other Comprehensive Income

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-Glossary Net Income

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-Appendix A

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+ Details

- Definition

The sum of dilutive potential common shares or units used in the calculation of the diluted per-share or per-unit computation.

+ References+ Details

- Definition

The average number of shares or units issued and outstanding that are used in calculating diluted EPS or earnings per unit (EPU), determined based on the timing of issuance of shares or units in the period.

+ References+ Details

- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

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-Glossary Weighted-Average Number of Common Shares Outstanding

-URI http://asc.fasb.org/extlink&oid=6528421

+ Details