Certain Financial Statement Information - Schedule of Property and equipment (Details) (USD $)	12 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Schedule of Property and equipment
Property and equipment, gross	$ 80,097,000		$ 99,442,000
Less: accumulated depreciation and amortization	(63,348,000)	[1]	(78,696,000)	[1]
Property and equipment, net	16,749,000		20,746,000
Fully depreciated assets written off	24.0
Impairment of capitalized mask costs			0
January 2015 Restructuring Plan
Schedule of Property and equipment
Impairment of capitalized mask costs	2,600,000
Minimum
Property, Plant and Equipment [Line Items]
Useful life	1 year
Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Machinery and Equipment
Schedule of Property and equipment
Property and equipment, gross	37,286,000	[1]	44,503,000	[1]
Machinery and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Machinery and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Leasehold Improvements
Schedule of Property and equipment
Property and equipment, gross	9,909,000		11,574,000
Leasehold Improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful life	1 year
Leasehold Improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years
Computers, Office Furniture and Equipment
Schedule of Property and equipment
Property and equipment, gross	$ 32,902,000	[1]	$ 43,365,000	[1]
Computers, Office Furniture and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful life	3 years
Computers, Office Furniture and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful life	5 years

[1] During the fiscal year ended March 31, 2015, the Company wrote-off fully depreciated assets with an acquired cost of $24.0 million. Also the Company wrote-off of a capitalized mask of $2.6 million as a result of recent restructuring. Refer to Note 7, Restructuring, to the Consolidated Financial Statements for additional information.