Document and Entity Information - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Mar. 03, 2021	Jun. 30, 2020
Document and Entity Information
Document Type	10-K
Document Period End Date	Dec. 31, 2020
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		129,654,575
Entity Central Index Key	0000894158
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Amendment Flag	false
Trading Symbol	SYN
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 8,460