Certain Financial Statement Information - Schedule of Property and equipment (Details) (USD $) In Thousands, unless otherwise specified					12 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Mar. 31, 2013 Minimum [Member]	Mar. 31, 2013 Maximum [Member]	Mar. 31, 2013 Machinery and Equipment [Member] Minimum [Member]		Mar. 31, 2013 Machinery and Equipment [Member] Maximum [Member]		Mar. 31, 2013 Leasehold Improvements [Member] Minimum [Member]	Mar. 31, 2013 Leasehold Improvements [Member] Maximum [Member]	Mar. 31, 2013 Computers, Office Furniture and Equipment [Member] Minimum [Member]	Mar. 31, 2013 Computers, Office Furniture and Equipment [Member] Maximum [Member]	Mar. 31, 2013 Buildings [Member]
Schedule of Property and equipment
Useful life					1 year	31 years 6 months	5 years	[1]	7 years	[1]	1 year	15 years	3 years	7 years	31 years 6 months
Machinery and equipment	$ 40,063	[1]	$ 36,600	[1]
Leasehold improvements	14,202		14,228
Computers, office furniture and equipment	43,485		43,929
Buildings	2,756		2,756
Land	9,800		9,800
Property and equipment, gross	110,306		107,313
Less: accumulated depreciation and amortization	(75,915)		(69,213)
Property and equipment, net	$ 34,391		$ 38,100

[1] Includes capitalized mask set costs