v3.19.3
Cover Page - shares
9 Months Ended
Sep. 30, 2019
Nov. 01, 2019
Cover [Abstract]    
Document Type 10-Q  
Document Quarterly Report true  
Entity Interactive Data Current Yes  
Document Transition Report false  
Amendment Flag false  
Document Fiscal Year Focus 2019  
Document Period End Date Sep. 30, 2019  
Document Fiscal Period Focus Q3  
Entity Registrant Name MADRIGAL PHARMACEUTICALS, INC.  
Entity Central Index Key 0001157601  
Entity File Number 001-33277  
Entity Tax Identification Number 04-3508648  
Entity Incorporation, State or Country Code DE  
Current Fiscal Year End Date --12-31  
Entity Current Reporting Status Yes  
Entity Shell Company false  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Address, Address Line One Four Tower Bridge  
Entity Address, Address Line Two 200 Barr Harbor Drive  
Entity Address, Address Line Three Suite 200  
Entity Address, City or Town West Conshohocken  
Entity Address, State or Province PA  
Entity Address, Postal Zip Code 19428  
City Area Code 267  
Local Phone Number 824-2827  
Trading Symbol MDGL  
Security Exchange Name NASDAQ  
Title of 12(b) Security Common Stock, $0.0001 Par Value Per Share  
Entity Common Stock, Shares Outstanding   15,429,154