Quarterly report pursuant to Section 13 or 15(d)

Stock Options (Tables)

Stock Options (Tables)

3 Months Ended

Mar. 31, 2018

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Summary of Assumptions Used Principally in Determining Fair Value of Options Granted

The weighted average assumptions used principally in determining the fair value of options granted to employees were as follows:

		Three Months Ended March 31,
		2018				2017
Risk free interest rate			2.34	%			2.17	%
Expected dividend yield			0	%			0	%
Expected term in years			6.25				6.35
Expected volatility			88.1	%			85.8	%
Estimated forfeiture rate			5	%			5	%

Summary of Option Activity

A summary of option activity for the three months ended March 31, 2018 is presented below:

										Weighted
										Average
						Weighted				Remaining
						Average				Contractual				Aggregate
Options		Shares				Exercise Price				Term in Years				Intrinsic Value
Outstanding at December 31, 2017			7,844,966			$	3.75
Granted			1,574,500				8.32
Exercised			(36,465	)			4.30
Forfeited			(40,417	)			7.28
Outstanding at March 31, 2018			9,342,584			$	4.50				7.85			$	29,325,265
Vested at March 31, 2018			5,049,555			$	2.41				6.93			$	24,544,006