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Stockholders' Equity - Summary of Restricted Stock, Restricted Stock Unit and Performance Stock Unit Activity (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Oct. 31, 2014
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Weighted Average Grant Price, Outstanding, April 30, 2014	$ 4.77
Weighted Average Grant Price, Granted	$ 4.91
Weighted Average Grant Price, Forfeited	$ 4.39
Weighted Average Grant Price, Outstanding, October 31, 2014	$ 4.79
Weighted Average Grant Price, Expected to vest, October 31, 2014	$ 4.40
Weighted Average Remaining Contractual Term, Outstanding	1 year 8 months 12 days
Weighted Average Remaining Contractual Term, Expected to vest	1 year 7 months 6 days
Aggregate Intrinsic Value, Outstanding, October 31, 2014	$ 191
Aggregate Intrinsic Value, Expected to vest, October 31, 2014	$ 173
Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Restricted Stock, Restricted Stock Units, and Performance Stock Units Outstanding, April 30, 2014	1,077
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Granted	370
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Forfeited	(32)
Restricted Stock, Restricted Stock Units, and Performance Stock Units Outstanding, October 31, 2014	1,052
Restricted Stock, Restricted Stock Units, and Performance Stock Units, Expected to vest, October 31, 2014	927
Class A Common Stock [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Weighted Average Grant Price Common Stock, Vested	$ 4.89
Class A Common Stock [Member] | Restricted Stock, Restricted Stock Units and Performance Stock Units [Member]
Schedule Of Restricted Stock Restricted Stock Unit And Performance Stock Unit Activity [Line Items]
Restricted Stock, Restricted Stock Units, and Performance Stock Units Common Stock, Vested	(363)

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Intrinsic value of equity-based awards excluding options expected to vest.

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The number of equity-based awards other than stock options that are expected to vest.

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The weighted average fair value as of the grant date of equity-based awards other than stock options for awards that are expected to vest.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMns' format, that are expected to vest.

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Intrinsic value of equity-based compensation awards outstanding. Excludes stock and unit options.

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The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

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Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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-Publisher FASB

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The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.

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Weighted average remaining contractual term for equity-based awards excluding options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.

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