Consolidated Statements of Stockholders' Equity / (Deficit) (USD $) In Thousands, except Share data, unless otherwise specified	Total	Common stock	Additional paid-in capital	Accumulated other comprehensive income (loss)	Deficit accumulated during the development stage	Series A convertible preferred stock	Series A convertible preferred stock Convertible preferred stock	Series A convertible preferred stock Common stock	Series A convertible preferred stock Additional paid-in capital	Series B convertible preferred stock	Series B convertible preferred stock Convertible preferred stock	Series B convertible preferred stock Common stock	Series B convertible preferred stock Additional paid-in capital
Balance at Apr. 04, 2011
Increase (decrease) in Stockholders' Equity
Sale of common stock to founders (in shares)		526,443
Issuance of convertible preferred stock, net of issuance costs of $2,246 at 2012 and $101 at 2011	$ (101)		$ (101)				$ 6,200
Issuance of convertible preferred stock, net of issuance costs of $2,246 at 2012 and $101 at 2011 (in shares)							6,200,000
Vesting of Founders Stock	1	1
Vesting of Founders Stock (in shares)		683,309
Stock-based compensation expense	347		347
Net loss	(2,624)				(2,624)
Balance at Dec. 31, 2011	(2,377)	1	246		(2,624)		6,200
Balance (in shares) at Dec. 31, 2011		1,209,752					6,200,000
Increase (decrease) in Stockholders' Equity
Issuance of convertible preferred stock, net of issuance costs of $2,246 at 2012 and $101 at 2011											34,992
Issuance of convertible preferred stock, net of issuance costs of $2,246 at 2012 and $101 at 2011 (in shares)											6,770,563
Conversion of Series A preferred stock to common stock	6,200	3	6,197
Common stock issued from the Conversion of Series A preferred stock to common stock (in shares)		3,064,753
Conversion of Series B preferred stock to common stock	34,992	7	34,985
Common stock issued from the Conversion of Series B preferred stock to common stock (in shares)		6,770,563
Conversion of preferred stock to common stock						6,200	(6,200)	3	6,197	34,992	(34,992)	7	34,985
Conversion of preferred stock to common stock (in shares)							(6,200,000)	3,064,753			(6,770,563)	6,770,563
Common stock issued in a private placement, net of issuance costs of $2,348 at 2013 and $898 at 2012	4,039	1	4,038
Common stock issued in a private placement, net of issuance costs of $2,348 at 2013 and $898 at 2012 (in shares)		897,554
Vesting of Founders Stock	1	1
Vesting of Founders Stock (in shares)		674,505
Exercise of stock options (in shares)		5,792
Stock-based compensation expense	1,382		1,382
Unrealized gain (loss) on investments	(6)			(6)
Net loss	(13,510)				(13,510)
Balance at Dec. 31, 2012	30,721	13	46,848	(6)	(16,134)
Balance (in shares) at Dec. 31, 2012		12,622,919
Increase (decrease) in Stockholders' Equity
Common stock issued in a private placement, net of issuance costs of $2,348 at 2013 and $898 at 2012	32,656	4	32,652
Common stock issued in a private placement, net of issuance costs of $2,348 at 2013 and $898 at 2012 (in shares)		3,888,880
Issuance of shares to Intrexon	2,500		2,500
Issuance of shares to Intrexon (in shares)		273,224
Vesting of Founders Stock	1	1
Vesting of Founders Stock (in shares)		658,060
Exercise of stock options	42		42
Exercise of stock options (in shares)		42,799
Stock-based compensation expense	5,094		5,094
Vesting of restricted stock, net of shares withheld for taxes	(285)		(285)
Vesting of restricted stock, net of shares withheld for taxes (in shares)		55,244
Unrealized gain (loss) on investments	16			16
Net loss	(29,044)				(29,044)
Balance at Dec. 31, 2013	$ 41,701	$ 18	$ 86,851	$ 10	$ (45,178)
Balance (in shares) at Dec. 31, 2013		17,541,126