Preferred Stock and Stockholders' Equity - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	0 Months Ended			12 Months Ended	0 Months Ended
	Oct. 29, 2013	Jan. 20, 2012	Jan. 12, 2011	Dec. 31, 2014	Oct. 23, 2013	Jan. 31, 2012	Jan. 25, 2012	Feb. 17, 2015	Feb. 09, 2015	Feb. 03, 2015	Nov. 07, 2012	Feb. 02, 2015	Dec. 31, 2013	Apr. 26, 2006
Equity [Line Items]
Shares of authorized capital stock														280,000,000
Common stock, shares authorized				250,000,000									250,000,000	250,000,000
Common stock par value per share			$ 0.001	$ 0.001									$ 0.001	$ 0.001
Preferred stock, shares authorized														30,000,000
Preferred stock par value														$ 0.001
Common Stock Shares Sold	16,445,000	10,114,401	2,426,235
Proceeds from issuance of common stock	$ 57.6	$ 52.6	$ 11.6
Common stock price per share	$ 3.50	$ 5.20	$ 4.80
Common Stock Additional Shares Issued			3,636,926
Common stock, shares issued				104,452,105									100,159,618
Common stock, shares outstanding				104,452,105									100,159,618
Preferred stock, shares issued				0
Preferred stock, shares outstanding				0
Expected net proceeds from issuance of common stock				94.6
J.P. Morgan Securities Inc.
Equity [Line Items]
Common Stock Additional Shares Issued	2,145,000				14,300,000	464,401	9,650,000
Issuance & sale of common stock in public offering price per share		$ 5.20			$ 3.50
Sale of stock price per share		$ 4.888			$ 3.29
Option granted, exercisable period		30 days			30 days
Option to purchase common stock		1,447,500			2,145,000
Subsequent Event | J.P. Morgan Securities Inc.
Equity [Line Items]
Common Stock Additional Shares Issued								1,500,000	10,000,000	10,000,000
Issuance & sale of common stock in public offering price per share										$ 8.75
Sale of stock price per share										$ 8.225
Option granted, exercisable period										30 days
Option to purchase common stock										1,500,000
Expected net proceeds from issuance of common stock								$ 94.2
Intrexon Corporation
Equity [Line Items]
Common Stock Additional Shares Issued	2,857,143						1,923,075				3,636,926
Intrexon Corporation | Subsequent Event
Equity [Line Items]
Common Stock Additional Shares Issued												1,440,000