Income Taxes - Components of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Apr. 01, 2012
Deferred tax assets:
Reserves and accruals not currently deductible	$ 16,968	$ 19,830
Stock-based compensation	18,036	17,237
Net operating loss carryforwards	12,408	14,635
Research credits	17,103	11,222
Investment securities	1,267	1,386
Other	657	2,828
Total gross deferred tax assets	66,439	67,138
Valuation allowance	(1,239)	(1,540)
Total deferred tax assets, net of valuation allowance	65,200	65,598
Deferred tax liabilities:
State income taxes	9,315	8,266
Property and equipment	6,149	7,044
Research and development expenditures	4,198	2,924
Purchased intangible assets	510	26
Total deferred tax liabilities	20,172	18,260
Net deferred tax assets	$ 45,028	$ 47,338