Net Earnings (Loss) Per Share - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended						9 Months Ended
	Jan. 25, 2020	Oct. 26, 2019	Jul. 27, 2019	Jan. 26, 2019	Oct. 27, 2018	Jul. 28, 2018	Jan. 25, 2020	Jan. 26, 2019	Dec. 14, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Stock Repurchase Program, Authorized Amount									$ 50,000
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 26,669						$ 26,669
Shares Paid for Tax Withholding for Share Based Compensation							374,733
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	3,682,169			1,412,951			1,348,949	2,844,886
Net Income (Loss) Attributable to Parent	$ (1,693)	$ 35,931	$ (32,155)	$ 769	$ 59,697	$ (38,622)	$ 2,083	$ 21,844
Net Income (Loss) Attributable to Parent, Diluted	$ (1,693)			$ 769			$ 2,082	$ 21,835
Weighted Average Number of Shares Outstanding, Basic	48,298,000			47,561,000			47,911,000	47,220,000
Weighted Average Number of Shares Outstanding, Diluted	48,298,000			47,937,000			48,767,000	47,772,000
Earnings Per Share, Basic	$ (0.04)			$ 0.02			$ 0.04	$ 0.46
Earnings Per Share, Diluted	$ (0.04)			$ 0.02			$ 0.04	$ 0.46
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic	$ 0			$ 0			$ (1)	$ (9)
Net Income (Loss) Available to Common Stockholders, Basic	(1,693)			769			2,082	21,835
Undistributed Earnings, Basic	0			0			1	9
Undistributed Earnings (Loss) Allocated to Participating Securities, Diluted	$ 0			$ 0			$ (1)	$ (9)
Average dilutive restricted stock units	0			178,000			403,000	403,000
Average dilutive performance shares	0			45,000			9,000	41,000
Average dilutive restricted shares	0			3,000			12,000	10,000
Average Dilutive Performance Share Units	0			150,000			432,000	98,000