Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 04, 2021
Document and Entity Information
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Entity Registrant Name	Synthetic Biologics, Inc.
Title of 12(b) Security	Common Stock
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	true
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		132,042,538
Entity Central Index Key	0000894158
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Trading Symbol	SYN