Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Income Taxes [Abstract]
Net operating loss carryforwards	$ 272,498	$ 260,254
Research and development and other tax credit carryforwards	10,655	10,613
Accruals and reserves	37,153	36,214
Fixed assets and intangible assets	2,432	2,855
Other	18,514us-gaap_DeferredTaxAssetsOther	19,594us-gaap_DeferredTaxAssetsOther
Gross deferred tax assets	341,252us-gaap_DeferredTaxAssetsGross	329,530us-gaap_DeferredTaxAssetsGross
Valuation allowance	(294,860)	(282,824)
Total deferred tax assets	46,392us-gaap_DeferredTaxAssetsNet	46,706us-gaap_DeferredTaxAssetsNet
Intercompany debt	(36,298)	(36,102)
Other	(10,174)us-gaap_DeferredTaxLiabilitiesOther	(10,641)us-gaap_DeferredTaxLiabilitiesOther
Total deferred tax liabilities	(46,472)us-gaap_DeferredTaxLiabilities	(46,743)us-gaap_DeferredTaxLiabilities
Net deferred tax liabilities	$ (80)us-gaap_DeferredTaxAssetsLiabilitiesNet	$ (37)us-gaap_DeferredTaxAssetsLiabilitiesNet

Deferred tax assets fixed assets and intangibles

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Deferred tax liabilities intercompany debt

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from in-process research and development costs expensed in connection with a business combination.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences not separately disclosed.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from reserves and accruals.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences net of deferred tax asset attributable to deductible temporary differences and carryforwards after valuation allowances.

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