Income Taxes - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands		Apr. 29, 2018	Apr. 30, 2017	May 01, 2016	May 03, 2015
deferred tax assets:
accounts receivable		$ 316	$ 447
inventories		2,217	2,196
compensation		3,438	6,222
liabilities and other		117	890
foreign income tax credits -U.S.		5,720	44,917
alternative minimum tax credit -U.S.			1,428
property, plant and equipment	[1]	226	245
loss carryforwards - U.S.		2,513	3,842
loss carryforwards - foreign		76	73
unrecognized tax benefits - U.S.			(3,842)
valuation allowances		(5,204)	(536)	$ (590)	$ (922)
total deferred tax assets		9,419	55,882
deferred tax liabilities:
undistributed earnings on foreign subsidiaries		(4,256)	(43,978)
unrecognized tax benefits - U.S.		(380)	(7,936)
property, plant and equipment	[2]	(4,352)	(5,546)
goodwill		(1,046)	(1,478)
other		(77)	(118)
total deferred tax liabilities		(10,111)	(59,056)
net deferred liabilities		$ (692)	$ (3,174)

[1] Pertains to the company's operations located in China.

[2] Pertains to the company's operations located in the U.S. and Canada.