Shareholders' Equity (Details) (USD $)	6 Months Ended
Oct. 29, 2011	Apr. 30, 2011	Oct. 30, 2010
Class of Stock [Line Items]
Dividend declared date	Nov. 17, 2009
Dividend payable, record date	Nov. 27, 2009
Common stock, par value	$ 0.001	$ 0.001	$ 0.001
Proportion of preferred stock in common stock	0.001
Preferred stock price per share	$ 100.00
Rights expiry date	November 17, 2012
Percent of assets sold to acquiring entity, threshold for discounted share purchase	50.00%
Rate of discounted share purchase	50.00%
Current beneficial ownership threshold percentage	20.00%
Series I Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock, par value per share	$ 0.001

Current Beneficial Ownership Threshold Percentage

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- Definition

Percent of Assets Sold to Acquiring Entity, Threshold for Discounted Share Purchase

+ References

No definition available.

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- Definition

Proportion Of Preferred Stock In Common Stock

+ References

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- Definition

Rate of Discounted Share Purchase

+ References

No definition available.

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- Definition

Rights expiry date

+ References

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- Definition

Face amount or stated value of common stock per share; generally not indicative of the fair market value per share.

+ References

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 30

-Article 5

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 4

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-Topic 210

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- Definition

The day, month and year (YYYY-MM-DD) that the dividend to be paid was declared.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 32

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-Topic 230

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- Definition

The date as of when a holder must own the stock to be entitled to the dividend. The ex-dividend date is generally 3 days before the record date.

+ References

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- Definition

Face amount or stated value per share of nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer); generally not indicative of the fair market value per share.

+ References

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

-Publisher FASB

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-Topic 210

-SubTopic 10

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-Paragraph 1

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-Publisher AICPA

-Name Accounting Principles Board Opinion (APB)

-Number 12

-Paragraph 10

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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-Paragraph 29

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- Definition

The price per share at which the preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at. The redemption features of this preferred stock are solely within the control of the issuer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

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