Stock-Based Compensation (Tables)

9 Months Ended

Sep. 30, 2018

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

Schedule of Valuation Assumptions

The fair value of each option award is estimated on the date of grant using the Black-Scholes option-pricing formula that uses assumptions noted in the following table. Expected volatilities and risk-free interest rates are based upon the expected life of the grant.

	Nine Months Ended September 30,
Assumptions	2018		2017
Expected dividends	—		—
Risk-free rate	2.38	%	2.00	%
Expected volatility	53.2% - 72.5%		58.0% - 69.7%
Expected term (in years)	3.2 - 3.3 years		3.2 - 3.3 years

Schedule of Stock Option Activity

A summary of option activity under the Director Plan, the 2009 Plan and the 2016 Plan as of September 30, 2018 and changes during the period are presented below:

	Number of Options	Weighted Average Exercise Price
Outstanding as of January 1, 2018	4,299,810	$	5.09
Issued	735,785	3.35
Exercised	(236,000)	1.04
Forfeited	(404,251)	7.71
Expired	—	—
Outstanding as of September 30, 2018	4,395,344	$	4.78
Exercisable as of September 30, 2018	3,247,214	$	4.74

Schedule of Stock Options Outstanding and Exercisable

The following tables summarize information regarding options outstanding and exercisable at September 30, 2018:

Outstanding:

Range of Exercise Prices	Stock Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life
$0.79 - $1.50	1,510,000	$	1.06	3.38
$1.51 - $5.50	898,207	3.22		8.35
$5.51 - $10.67	1,987,137	8.31		7.21
Total	4,395,344	$	4.78	6.12

Exercisable: 

Range of Exercise Prices	Stock Options Exercisable	Weighted Average Exercise Price
$0.79 - $1.50	1,510,000	$	1.06
$1.51 - $5.50	196,666	2.72
$5.51 - $10.67	1,540,548	8.60
Total	3,247,214	$	4.74

Schedule of Nonvested Restricted Stock Units Activity

The following table summarizes the number of unvested RSUs and their weighted average exercise price for the nine months ended September 30, 2018.

	Number of RSUs	Weighted Average Exercise Price
Non-vested balance at January 1, 2018	188,629	$	8.27
Changes during the period:
Shares granted	122,949	3.36
Shares vested	(101,607)	9.07
Shares forfeited	(26,047)	5.76
Non-vested balance at September 30, 2018	183,924	$	4.90