Stockholders' Equity (Deficit) (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options, Outstanding, Beginning Balance	5,246,465	3,879,239	2,592,009
Options, Granted during year	1,065,386	1,566,062	1,492,395
Options, Exercised during year	(399,654)	(188,699)	(134,534)
Options, Expired during year	(244,121)	0	(13,502)
Options, Forfeited during year	(571,402)	(10,137)	(57,129)
Options, Outstanding, Ending Balance	5,096,674	5,246,465	3,879,239
Options, Exercisable	2,695,278	2,269,438	1,676,016
Weighted Average Exercise Price, Outstanding, Beginning Balance	$ 6.76	$ 4.96	$ 5.12
Weighted Average Exercise Price, Granted during year	$ 10.54	$ 10.79	$ 4.61
Weighted Average Exercise Price, Exercised during year	$ 3.23	$ 3.42	$ 2.91
Weighted average Exercise Price, Expired during year	$ 9.17	$ 0	$ 9.86
Weighted Average Exercise Price, Forfeited during year	$ 10.49	$ 6.04	$ 6.68
Weighted Average Exercise Price, Outstanding, Ending Balance	$ 7.29	$ 6.76	$ 4.96
Weighted Average Exercise Price, Exercisable	$ 5.89	$ 4.59	$ 3.83
Weighted Average Remaining Contractual Term, Outstanding, Ending Balance	6 years 10 months 13 days	7 years 4 months 20 days	7 years 6 months
Weighted Average Remaining Contractual Term, Exercisable	5 years 8 months 5 days	5 years 8 months 23 days	5 years 8 months 19 days
Aggregate Intrinsic Value, Outstanding, Ending Balance	$ 6,329,518	$ 22,002,357	$ 16,198,044
Aggregate Intrinsic Value, Exercisable	$ 4,986,059	$ 13,968,005	$ 8,882,339