Reconciliation of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended	6 Months Ended
Oct. 27, 2018	Oct. 28, 2017	Oct. 27, 2018	Oct. 28, 2017
Numerator for basic income (loss) per share:
Net income (loss)	$ (27,394)	$ (30,094)	$ (44,432)	$ (40,872)
Less allocation of dividends to participating securities	(23)	(27)	(44)	(38)
Net loss available to common shareholders	(27,417)	(30,121)	(44,476)	(40,910)
Numerator for diluted loss per share:
Net loss available to common shareholders	$ (27,417)	$ (30,121)	$ (44,476)	$ (40,910)
Denominator for basic and diluted loss per share:
Basic and diluted weighted average common shares	72,935	72,597	72,811	72,525
Loss per common share:
Basic	$ (0.38)	$ (0.41)	$ (0.61)	$ (0.56)
Diluted	$ (0.38)	$ (0.41)	$ (0.61)	$ (0.56)

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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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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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.

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

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

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Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

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