Stock-Based Compensation (Schedule of Stock Option Activity) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Number of Shares
Options outstanding	3,822,887	2,584,553
Options assumed through merger with SafeStitch		709,550
Granted in period	787,300	603,139
Cancelled	(11,536)	(6,129)
Exercised	(13,838)	(68,227)
Options outstanding	4,584,813	3,822,887	2,584,553
Weighted-Average Exercise Price
Options outstanding	$ 1.30	$ 0.40
Options assumed through merger with SafeStitch		$ 3.75
Granted	$ 8.11	$ 2.20
Cancelled	$ 0.35	$ 0.40
Exercised	$ 0.52	$ 0.80
Options outstanding	$ 2.47	$ 1.30	$ 0.40
Weighted-Average Remaining Contractual Term (Years)
Options outstanding	7 years 9 months 29 days	7 years 11 months 12 days	8 years 8 months 12 days