Stock-Based Compensation (Schedule of Unvested Stock Option Activity) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Number of Shares
Granted in period	787,300	603,139
Unvested Options [Member]
Number of Shares
Unvested options	1,816,566	1,707,536
Unvested options assumed through merger with SafeStitch		223,200
Granted in period	787,300	603,139
Vested	(132,971)	(711,818)
Forfeited	(84)	(5,490)
Unvested options	2,470,811	1,816,566
Weighted-Average Fair Value
Unvested options	$ 1.10	$ 0.40
Unvested options assumed through merger with SafeStitch		$ 2.45
Granted	$ 3.10	$ 0.95
Vested	$ 0.85	$ 1.25
Forfeited	$ 0.20	$ 0.20
Options unvested	$ 1.72	$ 1.10