Stock-Based Compensation (Tables)

3 Months Ended

Mar. 31, 2018

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

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.



	Three months ended March 31,
Assumptions	2018		2017
Expected dividends	—	%	—	%
Risk-free rate	2.32	%	1.55	%
Expected volatility	60.5% - 60.9%		66.9% - 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 March 31, 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		$	4.76
Issued	580,535		3.33
Exercised	—		—
Forfeited	(84,740	)	7.43
Expired	—		—
Outstanding as of March 31, 2018	4,795,605		$	4.84

Exercisable as of March 31, 2018	3,553,271		$	4.63

Schedule of Stock Options Outstanding and Exercisable

The following tables summarize information regarding options outstanding and exercisable at March 31, 2018:

Outstanding:



Range of Exercise Prices	Stock Options Outstanding	Weighted Average Exercise Price		Weighted Average Remaining Contractual Life
$0.79 - $1.50	1,746,000	$	1.06	3.86
$1.51 - $5.50	797,169	3.19		8.62
$5.51 - $10.67	2,252,436	8.35		7.71
Total	4,795,605	$	4.84	6.46

Exercisable:



Range of Exercise Prices	Stock Options Exercisable	Weighted Average Exercise Price
$0.79 - $1.50	1,746,000	$	1.06
$1.51 - $5.50	205,666	2.77
$5.51 - $10.67	1,601,605	8.76
Total	3,553,271	$	4.63

Schedule of Nonvested Restricted Stock Units Activity

The following table summarizes the number of unvested RSUs and their weighted average exercise price for the three months ended March 31, 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		3.46
Shares vested	(96,608	)	8.16
Shares forfeited	—		—
Non-vested balance at March 31, 2018	214,970		$	5.08