Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2020	Feb. 24, 2021	Jun. 30, 2020
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2020
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	FY
Entity Registrant Name	ZIOPHARM Oncology, Inc.
Entity Central Index Key	0001107421
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Trading Symbol	ZIOP
Document Transition Report	false
Document Annual Report	true
Security Exchange Name	NASDAQ
Title of 12(b) Security	Common Stock
Entity File Number	001-33038
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	One First Avenue
Entity Address, Address Line Two	Parris Building 34, Navy Yard Plaza
Entity Address, City or Town	Boston
Entity Address, State or Province	MA
Entity Address, Postal Zip Code	02129
Entity Tax Identification Number	84-1475642
City Area Code	617
Local Phone Number	259-1970
Entity Well-known Seasoned Issuer	Yes
Entity Current Reporting Status	Yes
Entity Voluntary Filers	No
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Common Stock, Shares Outstanding		214,667,023
Entity Public Float			$ 687,342,598