Document and Entity Information - USD ($)
12 Months Ended
Dec. 31, 2018
Feb. 21, 2019
Jun. 29, 2018
Document and Entity Information      
Entity Registrant Name TrueCar, Inc.    
Entity Central Index Key 0001327318    
Current Fiscal Year End Date --12-31    
Entity Filer Category Large Accelerated Filer    
Entity Emerging Growth Company false    
Entity Small Business false    
Document Type 10-K    
Entity Current Reporting Status Yes    
Document Period End Date Dec. 31, 2018    
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus (Q1,Q2,Q3,FY) FY    
Amendment Flag false    
Entity Common Stock, Shares Outstanding   104,882,802  
Entity Well-known Seasoned Issuer Yes    
Entity Shell Company false    
Entity Voluntary Filers No    
Entity Public Float     $ 934,840,357