Subsequent Events - Additional Information (Detail) (USD $)	0 Months Ended				1 Months Ended	0 Months Ended	33 Months Ended	0 Months Ended
	Mar. 26, 2014	Jan. 27, 2015	Feb. 23, 2015	Feb. 27, 2015	Aug. 13, 2013	Jan. 13, 2015	Oct. 31, 2013	Feb. 09, 2015	Dec. 31, 2014
Subsequent Event [Line Items]
Securities purchase agreements, share	972,004
Securities purchase agreements, price per share	$ 25.72
Subsequent Event
Subsequent Event [Line Items]
Securities purchase agreements, share		4,312,500
Securities purchase agreements, price per share		$ 27.00
Proceeds from Issuance of Common Stock		$ 110,000,000
Underwriting discounts and commissions		6,100,000
Offering expense paid		300,000
Subsequent Event | ActoGeniX NV
Subsequent Event [Line Items]
Percentage of outstanding common stock acquired			100.00%
Consideration paid			30,000,000
Business acquisition, consideration paid, shares issued			965,377
Subsequent Event | Exemplar Genetics, LLC
Subsequent Event [Line Items]
Purchase of additional equity interest from noncontrolling interest of majority owned subsidiary			1,600,000
Shares issued by parent for purchase of additional equity interest from noncontrolling interest of majority owned subsidiary			307,074
Subsequent Event | Okanagan Specialty Fruits Inc
Subsequent Event [Line Items]
Business acquisition, pending close, percentage of voting interests to be acquired				100.00%
Business acquisition, pending close, equity interests issuable				31,000,000
Business acquisition, pending close, cash portion of acquisition price				10,000,000
Exercise of Overallotment Option by Underwriters
Subsequent Event [Line Items]
Securities purchase agreements, share					1,499,999
Exercise of Overallotment Option by Underwriters | Subsequent Event
Subsequent Event [Line Items]
Securities purchase agreements, share		562,500
University of Texas M.D. Anderson Cancer Center | Subsequent Event
Subsequent Event [Line Items]
Stock to be issued, shares, new issues						2,100,085
Stock to be issued, value, new issues						59,600,000
ZIOPHARM Oncology, Inc.
Subsequent Event [Line Items]
Shares of common stock purchased from collaborative partners, value							30,982,000
Purchase commitment									19,081,000
ZIOPHARM Oncology, Inc. | Subsequent Event
Subsequent Event [Line Items]
Annual funding commitment term						3 years
Shares of common stock purchased from collaborative partners, value								12,600,000
Purchase commitment								6,481,000
Affiliates Of Third Security
Subsequent Event [Line Items]
Securities purchase agreements, share	243,001
Affiliates Of Third Security | Subsequent Event
Subsequent Event [Line Items]
Securities purchase agreements, share		555,556
Minimum | ZIOPHARM Oncology, Inc. | Subsequent Event
Subsequent Event [Line Items]
Other Commitment						15,000,000
Maximum | ZIOPHARM Oncology, Inc. | Subsequent Event
Subsequent Event [Line Items]
Other Commitment						$ 20,000,000