Reconciliation of Basic and Diluted Income (Loss) Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Jul. 28, 2018	Jul. 29, 2017
Numerator for basic income (loss) per share:
Net income (loss)	$ (17,038)	$ (10,778)
Less allocation of dividends to participating securities	(21)	(11)
Net loss available to common shareholders	(17,059)	(10,789)
Numerator for diluted loss per share:
Net loss available to common shareholders	$ (17,059)	$ (10,789)
Denominator for basic and diluted loss per share:
Basic and diluted weighted average common shares	72,686	72,453
Loss per common share:
Basic	$ (0.23)	$ (0.15)
Diluted	$ (0.23)	$ (0.15)