Shareholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended				12 Months Ended
	Aug. 31, 2015	Jun. 30, 2015	Jan. 31, 2015	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Class of Stock [Line Items]
Shares issued in public or private offerings, shares	5,609,756		4,312,500	972,004
Value of shares issued in public or private offerings	$ 218,193		$ 110,041			$ 328,234	$ 25,000
Underwriting discounts and commissions	11,500		6,086
Capitalized offering expenses	$ 306		$ 311
Proceeds from issuance of shares in a private placement				$ 25,000	$ 0	0	$ 25,000
Affiliates Of Third Security
Class of Stock [Line Items]
Shares issued in public or private offerings, shares			555,556	243,001
Value of shares issued in public or private offerings				$ 6,250
ZIOPHARM Oncology, Inc.
Class of Stock [Line Items]
Noncash dividend, shares		17,830,305
Realized investment gain						$ 81,401
Intrexon Stock Option Plans
Class of Stock [Line Items]
Adjustment due to dividend (in shares)						312,795
Adjustment due to dividend (in usd per share)						$ 25.40