Cover Page - USD ($)	12 Months Ended
	Dec. 31, 2019	Feb. 14, 2020	Jun. 28, 2019
Cover [Abstract]
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2019
Document Fiscal Year Focus	2019
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
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Public Float			$ 834,869,811
Entity Common Stock, Shares Outstanding		212,999,979
Entity Interactive Data Current	Yes
Title of 12(b) Security	Common Stock
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity Address, State or Province	MA