Certain Financial Statement Information - Schedule of Purchased Inatngible Assets (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	$ 493,636	$ 493,636
Intangible assets, Accumulated Amortization and Impairments	(493,636)	(493,531)
Intangible assets, Net	0	105
Developed Technology In Process Research And Development
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	425,000	425,000
Intangible assets, Accumulated Amortization and Impairments	(425,000)	(425,000)
Intangible assets, Net	0	0
Intangible assets, Weighted average useful remaining life	0 years	0 years
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	6,330	6,330
Intangible assets, Accumulated Amortization and Impairments	(6,330)	(6,225)
Intangible assets, Net	0	105
Intangible assets, Weighted average useful remaining life	0 years	5 months 12 days
Patents Core Technology Rights Tradename
Finite-Lived Intangible Assets [Line Items]
Intangible assets, Gross	62,306	62,306
Intangible assets, Accumulated Amortization and Impairments	(62,306)	(62,306)
Intangible assets, Net	$ 0	$ 0
Intangible assets, Weighted average useful remaining life	0 years	0 years