v2.4.1.9
Income Taxes - Schedule of Tax Effects of Temporary Differences and Carryforwards that Rise to Significant Deferred Tax Assets and Liabilities (Detail) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Deferred tax assets:    
Net operating loss carryforwards $ 63,116us-gaap_DeferredTaxAssetsOperatingLossCarryforwards $ 62,863us-gaap_DeferredTaxAssetsOperatingLossCarryforwards
Tax credit carryforwards 4,065us-gaap_DeferredTaxAssetsTaxCreditCarryforwards 3,973us-gaap_DeferredTaxAssetsTaxCreditCarryforwards
Accruals 942us-gaap_DeferredTaxAssetsTaxDeferredExpense 1,097us-gaap_DeferredTaxAssetsTaxDeferredExpense
Property and equipment 0us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment 147us-gaap_DeferredTaxAssetsPropertyPlantAndEquipment
Other 551us-gaap_DeferredTaxAssetsOther 97us-gaap_DeferredTaxAssetsOther
Gross deferred tax assets 68,674us-gaap_DeferredTaxAssetsGross 68,177us-gaap_DeferredTaxAssetsGross
Deferred tax liabilities:    
Property and equipment (8)us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment 0us-gaap_DeferredTaxLiabilitiesPropertyPlantAndEquipment
Purchased Intangible (2,349)us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets 0us-gaap_DeferredTaxLiabilitiesGoodwillAndIntangibleAssetsIntangibleAssets
Total deferred tax liabilities (2,357)us-gaap_DeferredIncomeTaxLiabilities 0us-gaap_DeferredIncomeTaxLiabilities
Valuation allowance (66,317)us-gaap_DeferredTaxAssetsValuationAllowance (68,177)us-gaap_DeferredTaxAssetsValuationAllowance
Net deferred tax assets $ 0us-gaap_DeferredTaxAssetsNet $ 0us-gaap_DeferredTaxAssetsNet