Revision of Prior Period Financial Statements (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended			6 Months Ended
	Sep. 30, 2012	Oct. 02, 2011		Sep. 30, 2012	Oct. 02, 2011
Consolidated Statement of Operations
Cost of revenues	$ 58,774	$ 64,685		$ 116,422	$ 134,534
Gross profit	74,627	73,633		147,140	153,069
Research and development	42,387	39,184		83,931	78,999
Selling, general and administrative	32,750	24,888		69,162	50,817
Total operating expenses	75,137	64,072		153,093	129,816
Operating income (loss)	(510)	9,561		(5,953)	23,253
Income from continuing operations before income taxes	(716)	7,733		(4,159)	21,469
Provision for income taxes	(33)	(367)		(4,019)	600
Net income (loss) from continuing operations	(683)	8,100		(140)	20,869
Net income	(73)	46,747		(4,388)	51,901
Basic income (loss) per share:
Basic net income (loss) per share - continuing operations (in dollars per share)	$ 0.00	$ 0.06		$ 0.00	$ 0.14
Basic net income (loss) per share (in dollars per share)	$ 0.00	$ 0.32		$ (0.03)	$ 0.35
Diluted net income (loss) per share:
Diluted net income (loss) per share - continuing operations (in dollars per share)	$ 0.00	$ 0.06		$ 0.00	$ 0.14
Diluted net income (loss) per share (in dollars per share)	$ 0.00	$ 0.32		$ (0.03)	$ 0.35
Adjustments [Member]
Consolidated Statement of Operations
Cost of revenues		670			2,950
Gross profit		(670)			(2,950)
Research and development		(383)			(235)
Selling, general and administrative		20			101
Total operating expenses		(363)			(134)
Operating income (loss)		(307)			(2,816)
Income from continuing operations before income taxes		(307)			(2,816)
Provision for income taxes		0			20
Net income (loss) from continuing operations		(307)			(2,836)
Net income		(307)			(2,836)
Basic income (loss) per share:
Basic net income (loss) per share - continuing operations (in dollars per share)		$ 0.00			$ (0.02)
Basic net income (loss) per share (in dollars per share)		$ (0.01)			$ (0.02)
Diluted net income (loss) per share:
Diluted net income (loss) per share - continuing operations (in dollars per share)		$ 0.00			$ (0.02)
Diluted net income (loss) per share (in dollars per share)		$ 0.00			$ (0.02)
As Reported [Member]
Consolidated Statement of Operations
Cost of revenues		64,015	[1]		131,584	[1]
Gross profit		74,303	[1]		156,019	[1]
Research and development		39,567	[1]		79,234	[1]
Selling, general and administrative		24,868	[1]		50,716	[1]
Total operating expenses		64,435	[1]		129,950	[1]
Operating income (loss)		9,868	[1]		26,069	[1]
Income from continuing operations before income taxes		8,040	[1]		24,285	[1]
Provision for income taxes		(367)	[1]		580	[1]
Net income (loss) from continuing operations		8,407	[1]		23,705	[1]
Net income		$ 47,054	[1]		$ 54,737	[1]
Basic income (loss) per share:
Basic net income (loss) per share - continuing operations (in dollars per share)		$ 0.06	[1]		$ 0.16	[1]
Basic net income (loss) per share (in dollars per share)		$ 0.33	[1]		$ 0.37	[1]
Diluted net income (loss) per share:
Diluted net income (loss) per share - continuing operations (in dollars per share)		$ 0.06	[1]		$ 0.16	[1]
Diluted net income (loss) per share (in dollars per share)		$ 0.32	[1]		$ 0.37	[1]

[1] Reflects previously reported amounts as adjusted for discontinued operations (see Note 5)