Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2014

Employee Benefit Plans

Assumptions made for the purpose of estimating fair value

	2014	2013	2012
Dividend yield:	0%	0%	0%
Expected term of options (years):	6	6	6
Risk free interest rate:	1.77% - 1.94%	0.93% - 1.70%	0.80% - 1.16%
Volatility:	107% - 114%	92% - 107%	80%

Schedule of Share-based Compensation, Stock Options, Activity

	Shares			Weighted Average Exercise Price		Weighted Average Remaining Contractual Terms		Aggregate Instrinsic Value
Options outstanding at December 31, 2013		4,703,326		$	3.22		8.7
Granted		4,246,000			4.86
Exercised		(417,852	)		0.97
Forfeited		(143,053	)		5.25
Expired		(21,150	)		77.22
Options outstanding at December 31, 2014		8,367,271		$	3.94		8.7		7,865,235
Options exercisable at December 31, 2014		2,266,607			5.16		7.0		4,895,871
Options unvested at December 31, 2014		6,100,664		$	3.49		9.3		2,989,325

Nonvested Restricted Stock Shares Activity

	Shares			Aggregate Instrinsic Value
Unvested restricted stock at December 31, 2013		650,002
Granted		40,000
Vested		(216,666	)
Unvested restricted stock at December 31, 2014		473,336		$	1,420,008