Warrants (Details) (USD $)	0 Months Ended	12 Months Ended
	Dec. 17, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Additional information
Closing price of common stock as reported on NASDAQ (in dollars per share)		$ 2.78	$ 3.48	$ 2.27
Warrants
Number of warrants
Outstanding at the beginning of the period (in shares)		726,858
Warrants exercised (number of warrants)		(247,950)
Warrants cancelled (number of warrants)		(257,008)
Outstanding at the end of the period (in shares)		221,900	726,858
Warrants exercisable at the end of the period (in shares)		221,900
Vested and expected to vest at the end of the period (in shares)		221,900
Weighted-average exercise price
Outstanding at the beginning of the period (in dollars per share)		$ 2.29
Warrants exercised (in dollars per share)		$ 0.38
Warrants cancelled (in dollars per share)		$ 3.94
Outstanding at the end of the period (in dollars per share)		$ 2.50	$ 2.29
Warrants exercisable at the end of the period (in dollars per share)		$ 2.50
Vested and expected to vest at the end of the period (in dollars per share)		$ 2.50
Weighted-average remaining contractual life (years)
Outstanding at the end of the period		4 months 2 days	1 year 3 months 4 days
Warrants exercisable at the end of the period		4 months 2 days
Vested and expected to vest at the end of the period		4 months 2 days
Aggregate intrinsic value
Outstanding at the end of the period (in dollars)		$ 224,707	$ 1,236,845
Exercisable at the end of the period (in dollars)		224,707
Vested and expected to vest at the end of the period (in dollars)		224,707
Additional information
Weighted average grant date fair value for warrants granted during the period (in dollars per share)				$ 2.83
Total fair value of warrants vested during the period (in dollars)				11,254
Total intrinsic value of warrants exercised during the period (in dollars)		$ 594,002	$ 2,376,589	$ 26,975
Shares issued on warrant exercise (in shares)	917,602	213,123
Number of shares subject to warrant that were cancelled	464,115	34,827
Warrants | Minimum
Weighted-average exercise price
Warrants exercisable at the end of the period (in dollars per share)		$ 0.25
Warrants | Maximum
Weighted-average exercise price
Warrants exercisable at the end of the period (in dollars per share)		$ 5.50