Summary of Unvested Share Activity for Non-Employee Directors (Detail) (Unvested Shares, Non Employee Director, USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Unvested Shares | Non Employee Director
Shares
Outstanding, beginning	47,428	80,078
Granted	47,428	182,355
Vested		(215,005)
Forfeited
Outstanding, ending	47,428	47,428
Weighted Average Exercise Price
Outstanding, beginning	$ 1.69	$ 1.77
Granted		$ 0.85
Vested		$ 1.01
Forfeited
Outstanding, ending	$ 1.69	$ 1.69