Document and Entity Information - shares
3 Months Ended
Mar. 31, 2018
May 03, 2018
Document and Entity Information    
Entity Registrant Name TrueCar, Inc.  
Entity Central Index Key 0001327318  
Document Type 10-Q  
Document Period End Date Mar. 31, 2018  
Entity Current Reporting Status Yes  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Entity Filer Category Large Accelerated Filer  
Entity Common Stock, Shares Outstanding   100,932,475