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Income Taxes - Additional Information (Detail) (USD $)
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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 Taxes Disclosure [Line Items] | |||
| Income tax (benefit) provision | $ (202,000)us-gaap_IncomeTaxExpenseBenefit | $ 202,000us-gaap_IncomeTaxExpenseBenefit | |
| NOL DTA related to excess benefits from stock option exercises | 400,000thld_NetOperatingLossDeferredTaxAssetFromExcessBenefitsFromStockOptionExercises | ||
| Increase in valuation allowance | 7,800,000us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount | 11,600,000us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount | 7,800,000us-gaap_ValuationAllowanceDeferredTaxAssetChangeInAmount |
| Accrued interest or penalties | 0us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued | 0us-gaap_IncomeTaxExaminationPenaltiesAndInterestAccrued | |
| Federal [Member] | |||
| Income Taxes Disclosure [Line Items] | |||
| Federal and State net operating loss carryforwards |
82,000,000us-gaap_OperatingLossCarryforwards / us-gaap_IncomeTaxAuthorityNameAxis = us-gaap_InternalRevenueServiceIRSMember |
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| Year net operating loss carryforwards begin to expire | 2021 | ||
| Research and development credits |
4,100,000us-gaap_TaxCreditCarryforwardAmount / us-gaap_IncomeTaxAuthorityNameAxis = us-gaap_InternalRevenueServiceIRSMember |
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| Year research and development credits begin to expire | 2022 | ||
| State [Member] | |||
| Income Taxes Disclosure [Line Items] | |||
| Federal and State net operating loss carryforwards |
87,000,000us-gaap_OperatingLossCarryforwards / us-gaap_IncomeTaxAuthorityAxis = us-gaap_StateAndLocalJurisdictionMember |
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| Year net operating loss carryforwards begin to expire | 2015 | ||
| Research and development credits |
$ 4,900,000us-gaap_TaxCreditCarryforwardAmount / us-gaap_IncomeTaxAuthorityAxis = us-gaap_StateAndLocalJurisdictionMember |
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- Details
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- Definition
Amount of net operating loss deferred tax assets related to excess benefits from stock option exercises. No definition available.
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- Definition
Operating loss carryforward expiration start year. No definition available.
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- Definition
Research and development tax credits expiration start year. No definition available.
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- Definition
The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount 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
Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
The amount of the tax credit carryforward, before tax effects, available to reduce future taxable income under enacted tax laws. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Definition
Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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- Details
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- Details
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