Annual report pursuant to Section 13 and 15(d)

Document and Entity Information

Document and Entity Information - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2018
Mar. 13, 2019
Sep. 27, 2018
Document And Entity Information [Abstract]      
Entity Registrant Name Ra Medical Systems, Inc.    
Entity Central Index Key 0001716621    
Document Type 10-K    
Document Period End Date Dec. 31, 2018    
Amendment Flag false    
Entity Voluntary Filers No    
Entity Well Known Seasoned Issuer No    
Entity Current Reporting Status Yes    
Current Fiscal Year End Date --12-31    
Trading Symbol RMED    
Entity Filer Category Non-accelerated Filer    
Entity Common Stock, Shares Outstanding   12,689,251  
Entity Public Float     $ 157.8
Document Fiscal Year Focus 2018    
Document Fiscal Period Focus FY    
Entity Emerging Growth Company true    
Entity Small Business true    
Entity Shell Company false    
Entity Ex transition period false