XML 25 R1.htm IDEA: XBRL DOCUMENT v3.20.4
Cover Page - USD ($)
$ in Billions
 12 Months Ended
Dec. 31, 2020
Feb. 22, 2021
Jun. 30, 2020
Cover [Abstract]      
Document Type 10-K    
Document Annual Report true    
Document Period End Date Dec. 31, 2020    
Document Transition Report false    
Entity File Number 001-36112    
Entity Registrant Name MACROGENICS, INC.    
Entity Incorporation, State or Country Code DE    
Entity Tax Identification Number 06-1591613    
Entity Address, Address Line One 9704 Medical Center Drive    
Entity Address, City or Town Rockville    
Entity Address, State or Province MD    
Entity Address, Postal Zip Code 20850    
City Area Code 301    
Local Phone Number 251-5172    
Title of 12(b) Security Common stock, par value $0.01 per share    
Trading Symbol MGNX    
Security Exchange Name NASDAQ    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Interactive Data Current Yes    
Entity Filer Category Large Accelerated Filer    
Entity Small Business false    
Entity Emerging Growth Company false    
ICFR Auditor Attestation Flag true    
Entity Shell Company false    
Entity Public Float     $ 1.5
Entity Common Stock, Shares Outstanding   56,258,468  
Documents Incorporated by Reference Portions of MacroGenics, Inc.'s definitive proxy statement for the 2021 annual meeting of stockholders are incorporated by reference into Part III of this Annual Report.    
Amendment Flag false    
Document Fiscal Year Focus 2020    
Document Fiscal Period Focus FY    
Entity Central Index Key 0001125345    
Current Fiscal Year End Date --12-31