Stockholders' Equity (Details 1) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Stockholders Equity [Line Items]
Outstanding, Number of Options, at January 1, 2015	18,986,395
Granted, Number of Options	765,549
Exercised, Number of Options	(1,031,774)
Forfeited/Expired, Number of Options	(1,233,890)
Outstanding, Number of Options, at September 30, 2015	17,486,280	18,986,395
Exercisable, Number of Options, at September 30, 2015	14,240,432
Vested and expected to vest, Number of Options	17,481,198
Outstanding, Weighted-Average Exercise Price, at January 1, 2015	$ 1.89
Granted, Weighted-Average Exercise Price	3.09
Exercised, Weighted-Average Exercise Price	0.54
Forfeited, Weighted-Average Exercise Price	0.83
Outstanding, Weighted-Average Exercise Price, at September 30, 2015	2.1	$ 1.89
Exercisable, Weighted-Average Exercise Price, at September 30, 2015	2.21
Vested and expected to vest, Weighted-Average Exercise Price	$ 2.1
Outstanding, Weighted-Average Remaining Contractual Life (in Years)	5 years 1 month 6 days	5 years 1 month 6 days
Exercisable, Weighted-Average Remaining Contractual Life (in Years)	4 years 7 months 6 days
Vested and expected to vest, Weighted-Average Remaining Contractual Life (in Years)	4 years 9 months 18 days
Outstanding, Aggregate Intrinsic Value, at January 1, 2015	$ 20,306,807
Exercised, Aggregate Intrinsic Value	68,400
Outstanding, Aggregate Intrinsic Value, at September 30, 2015	1,897,315	$ 20,306,807
Exercisable, Aggregate Intrinsic Value, at September 30, 2015	1,277,927
Vested and expected to vest, Aggregate Intrinsic Value	$ 1,897,315