Quarterly report pursuant to Section 13 or 15(d)

Document And Entity Information

Document And Entity Information - shares
3 Months Ended
Mar. 31, 2019
May 10, 2019
Document And Entity Information [Abstract]    
Entity Registrant Name Moleculin Biotech, Inc.  
Entity Central Index Key 0001659617  
Current Fiscal Year End Date --12-31  
Entity Filer Category Non-accelerated Filer  
Document Type 10-Q  
Document Period End Date Mar. 31, 2019  
Document Fiscal Year Focus 2019  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Trading Symbol MBRX  
Entity Common Stock, Shares Outstanding   45,192,048
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period true