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Income Taxes - Reconciliation of Federal Statutory Income Tax Rate (Detail)
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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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| Income Tax Disclosure [Abstract] | |||
| Federal statutory income tax rate | (34.00%)us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | (34.00%)us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate | (34.00%)us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate |
| Federal and state research and development tax credit | (4.40%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch | (9.00%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch | (1.20%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsResearch |
| State taxes, net of federal benefit | (4.00%)us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | (4.00%)us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes | (5.00%)us-gaap_EffectiveIncomeTaxRateReconciliationStateAndLocalIncomeTaxes |
| Orphan drug tax credit | (3.20%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsOther | (3.10%)us-gaap_EffectiveIncomeTaxRateReconciliationTaxCreditsOther | |
| Stock compensation expense | 0.60%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost | 0.60%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost | 0.20%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseShareBasedCompensationCost |
| Nondeductible Australia research and development expenses | 0.60%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment | 4.10%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment | 1.80%us-gaap_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseResearchAndDevelopment |
| Other items | 2.40%us-gaap_EffectiveIncomeTaxRateReconciliationOtherReconcilingItemsPercent | ||
| Change in deferred tax asset valuation allowance | 42.00%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance | 45.40%us-gaap_EffectiveIncomeTaxRateReconciliationChangeInDeferredTaxAssetsValuationAllowance | 38.20%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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- 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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- 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 research and development expense. 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 equity-based compensation costs. 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 the expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, that is attributable to tax exempt income, equity in earnings (loss) of an unconsolidated subsidiary, minority interest income (expense), tax holiday, disposition of a business, disposition of an asset, repatriation of foreign earnings, repatriation of foreign earnings jobs creation act of 2004, change in enacted tax rate, prior year income taxes, change in deferred tax asset valuation allowance, and other adjustments. No definition available.
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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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- 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 tax credits. 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 research tax credit. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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