Stockholders' Equity (Deficit) (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares [Roll Forward]
Options, Nonvested stock options, Beginning Balance	2,977,027	2,203,223	1,252,668
Options, Granted during year	1,065,386	1,566,062	1,492,395
Options, Vested during year	(1,069,615)	(782,121)	(484,711)
Options, Expired during year	0	0	0
Options, Forfeited during year	(571,402)	(10,137)	(57,129)
Options, Nonvested stock options, Ending Balance	2,401,396	2,977,027	2,203,223
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Weighted-Average Grant Date Value, Nonvested stock options, Beginning Balance	$ 6.62	$ 4.24	$ 5.34
Weighted-Average Grant Date Value, Granted during year	$ 8.62	$ 8.76	$ 3.42
Weighted-Average Grant Date Value, Vested during year	$ 6.61	$ 4.22	$ 4.51
Weighted-Average Grant Date Value, Expired during year	$ 0	$ 0	$ 0
Weighted-Average Grant Date Value, Forfeited during year	$ 8.36	$ 4.58	$ 4.61
Weighted-Average Grant Date Value, Nonvested stock options, Ending Balance	$ 7.07	$ 6.62	$ 4.24