Selected Balance Sheet Information (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Other Current Assets [Line Items]
Intrexon prepaid research and development expenses	$ 1,049	$ 1,067
Prepaid Clinical Research Organization expenses	5,458	0
Prepaid insurance	133	228
Other prepaid expenses	315	253
Total	$ 6,955	$ 1,548