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           Income Taxes (Detail 1) 
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        12 Months Ended | |||||||
|---|---|---|---|---|---|---|---|---|
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           Dec. 31, 2014 
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           Dec. 31, 2013 
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           Dec. 31, 2012 
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| Percentage of pre-tax income: | ||||||||
| U.S. federal statutory income tax rate | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | 35.00%us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | |||||
| State taxes, net of federal benefit | 5.00%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | 4.00%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | 4.00%us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | |||||
| Credits | 6.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits | 4.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits | 1.00%us-gaap_EffectiveIncomeTaxRateReconciliationTaxCredits | |||||
| Non-deductible items | (1.00%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense | (2.00%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense | (2.00%)us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpense | |||||
| Other | 0.00%us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments | [1] | (1.00%)us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments | [1] | (5.00%)us-gaap_EffectiveIncomeTaxRateReconciliationOtherAdjustments | [1] | ||
| Change in valuation allowance | (45.00%)us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance | (40.00%)us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance | (33.00%)us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance | |||||
| Effective income tax rate | 0.00%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 0.00%us-gaap_EffectiveIncomeTaxRateContinuingOperations | 0.00%us-gaap_EffectiveIncomeTaxRateContinuingOperations | |||||
          
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- Definition 
          Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Details 
          
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- Definition 
          Percentage of domestic federal statutory tax rate applicable to pretax income (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition 
          Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to changes in the valuation allowance for deferred tax assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to other adjustments. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations applicable to state and local income tax expense (benefit), net of federal tax expense (benefit). Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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| X | ||||||||||
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- Definition 
          Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to tax credits. Including, but not limited to, research credit, foreign tax credit, investment tax credit, and other tax credits. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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