Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2024	Mar. 13, 2025	Jun. 30, 2024
Document Information [Line Items]
Entity Central Index Key	0001659617
Entity Registrant Name	Moleculin Biotech, Inc.
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Period Focus	FY
Document Fiscal Year Focus	2024
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2024
Document Transition Report	false
Entity File Number	001-37758
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	47-4671997
Entity Address, Address Line One	5300 Memorial Drive, Suite 950
Entity Address, City or Town	Houston
Entity Address, State or Province	TX
Entity Address, Postal Zip Code	77007
City Area Code	713
Local Phone Number	300-5160
Title of 12(b) Security	Common Stock, par value $0.001 per share
Trading Symbol	MBRX
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
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
ICFR Auditor Attestation Flag	false
Document Financial Statement Error Correction [Flag]	false
Entity Shell Company	false
Entity Public Float			$ 9,000,000
Entity Common Stock, Shares Outstanding		14,000,494
Auditor Firm ID	248
Auditor Name	GRANT THORNTON LLP
Auditor Location	Fort Lauderdale, Florida