Product Warranty Accrual (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Dec. 29, 2012	Dec. 31, 2011	Dec. 29, 2012	Dec. 31, 2011
Product Warranty
Product warranty accrual, beginning	$ 6,096	$ 5,117	$ 4,187	$ 4,415
Warranty charges incurred, net	(1,603)	(1,248)	(5,513)	(5,199)
Provision for warranty charges	1,297	768	7,116	5,421
Product warranty accrual, ending	$ 5,790	$ 4,637	$ 5,790	$ 4,637