Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Deficit) - Financial Liabilities Subject to Fair Value Measurements (Detail)

v2.4.1.9
Stockholders' Equity (Deficit) - Financial Liabilities Subject to Fair Value Measurements (Detail) (Warrants, USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements   $ 23,421us-gaap_LiabilitiesFairValueDisclosure
Basis of Fair Value Measurements, Level 3
    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements   23,421us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember
March 2011 Warrants    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements 3,961us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember 		12,101us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember
March 2011 Warrants | Basis of Fair Value Measurements, Level 3    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements 3,961us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember 		12,101us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember
October 2009 Warrants    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements   11,320us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_OctoberTwoThousandNineWarrantsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember
October 2009 Warrants | Basis of Fair Value Measurements, Level 3    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements   $ 11,320us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_OctoberTwoThousandNineWarrantsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember