Certain Financial Statement Information Property and Equipment (Details) (USD $) In Thousands, unless otherwise specified					9 Months Ended
	Dec. 31, 2013		Mar. 31, 2013		Dec. 31, 2013 Machinery and Equipment [Member] Minimum [Member]	Dec. 31, 2013 Machinery and Equipment [Member] Maximum [Member]	Dec. 31, 2013 Leasehold Improvements [Member] Minimum [Member]	Dec. 31, 2013 Leasehold Improvements [Member] Maximum [Member]	Dec. 31, 2013 Computers, Office Furniture and Equipment [Member] Minimum [Member]	Dec. 31, 2013 Computers, Office Furniture and Equipment [Member] Maximum [Member]	Dec. 31, 2013 Buildings [Member]
Schedule of Property and equipment
Useful life					5 years	7 years	1 year	15 years	3 years	7 years	31 years 6 months
Machinery and equipment	$ 44,887	[1]	$ 40,063	[1]
Leasehold improvements	9,011	[2]	14,202
Computers, office furniture and equipment	43,992		43,485
Buildings	0	[2]	2,756
Land	0	[2]	9,800
Property and equipment, gross	97,890		110,306
Less: accumulated depreciation and amortization	(77,718)		(75,915)
Property and equipment, net	$ 20,172		$ 34,391	[3]

[1] Includes capitalized mask costs.

[2] December 31, 2013 balances exclude $14.3 million, including land, building and leasehold improvements related to the Company's headquarters in Sunnyvale, California, which have been reclassified as assets held for sale and included under current assets.

[3] Amounts have been derived from the March 31, 2013 audited consolidated financial statements.