Income Taxes - Differences Between Income Tax Expense at Federal Income Tax Rate and Effective Income Tax Rate (Detail)	3 Months Ended								12 Months Ended
	Apr. 29, 2018	Jan. 28, 2018	Oct. 29, 2017	Jul. 30, 2017	Apr. 30, 2017	Jan. 29, 2017	Oct. 30, 2016	Jul. 31, 2016	Apr. 29, 2018	Apr. 30, 2017	May 01, 2016
Income Tax Disclosure [Abstract]
federal income tax rate									30.40%	34.00%	34.00%
tax effects of the 2017 Tax Cuts and Jobs Act									(7.60%)
tax effects of Chinese foreign exchange (losses) gains									(2.80%)	1.60%	4.40%
reversal of foreign uncertain income tax position										(11.60%)
tax effects of stock-based compensation									(1.80%)
undistributed earnings from foreign subsidiaries									3.70%
other									(0.50%)	0.70%	0.90%
Effective income tax rate	(96.10%)	109.20%	34.20%	24.30%	11.10%	9.20%	37.50%	37.80%	21.40%	24.70%	39.30%