Quarterly report pursuant to Section 13 or 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
Mar. 31, 2015
Dec. 31, 2014
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements $ 20,185us-gaap_LiabilitiesFairValueDisclosure $ 3,961us-gaap_LiabilitiesFairValueDisclosure
Basis of Fair Value Measurements, Level 3    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements 20,185us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember 		3,961us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember
February 2015 Warrants    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements 13,493us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_FebruaryTwoThousandFifteenWarrantsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember 		 
February 2015 Warrants | Basis of Fair Value Measurements, Level 3    
Fair Value Inputs Liabilities Quantitative Information [Line Items]    
Financial liabilities subject to fair value measurements 13,493us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_FebruaryTwoThousandFifteenWarrantsMember
/ 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 6,692us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember 		3,961us-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 $ 6,692us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember 		$ 3,961us-gaap_LiabilitiesFairValueDisclosure
/ us-gaap_ClassOfWarrantOrRightAxis
= thld_MarchTwoThousandElevenWarrantsMember
/ us-gaap_FairValueByFairValueHierarchyLevelAxis
= us-gaap_FairValueInputsLevel3Member
/ us-gaap_FinancialInstrumentAxis
= us-gaap_WarrantMember