Stock-based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Summary of Company's Stock Option Plans

A following table summarizes stock option activity during the year ended December 31, 2017:

	Number of Options			Weighted- Average Exercise Price		Weighted- Average Remaining Contractual Life (year)		Aggregate Intrinsic Value (in thousands)
Outstanding, December 31, 2016		1,516,059		$	7.25		5.19	$	48
Granted		680,400			5.17
Exercised		—			—
Forfeited		(394,409	)		6.71
Outstanding, December 31, 2017		1,802,050		$	6.59		4.86	$	8
Vested		822,736			7.19		3.85		—
Unvested		979,314			6.08		5.71		8
Vested or expected to vest, December 31, 2017		1,802,050		$	6.59	4.86		$	8
Exercisable, December 31, 2017		822,736		$	7.19	3.85

Assumptions Used to Value Options Granted

	Years Ended December 31,
	2017		2016		2015
Risk free interest rate	1.45%-1.59%		0.85%-1.45%		0.87%-1.20%
Expected term	4.5-4.75 years		4.75 years		4.56-4.75 years
Dividend yield		—		—		—
Expected volatility	53.15%-55.20%		55.23%-79.29%		76.86%-83.09%

Summary of Company's Restricted Stock Activity and Related Information

A summary of the Company’s restricted stock activity and related information for the year ended December 31, 2017 is as follows:

	Shares			Weighted Average Grant Date Fair Value
Unvested, December 31, 2016		40,933		$	7.42
Granted		118,934		$	5.03
Vested		(40,933	)	$	7.42
Forfeited		(15,500	)	$	5.15
Unvested, December 31, 2017		103,434		$	5.01

Performance-Based Restricted Stock Units [Member]

Summary of Company's Restricted Stock Activity and Related Information

A summary of the Company’s performance-based restricted stock activity for the year ended December 31, 2017 is as follows:

	Performance-based Restricted Stock Units
Unvested, December 31, 2016		—
Granted		186,000
Vested		—
Forfeited		(109,550	)
Unvested, December 31, 2017		76,450

Employees [Member]

Assumptions Used to Value Options Granted

The weighted-average fair value of the options granted to employees during the years ended December 31, 2017, 2016 and 2015 was $2.43, $4.66 and $4.38, respectively based on the following assumptions:

	Years Ended December 31,
	2017		2016		2015
Risk free interest rate	1.45%-1.59%		0.85%-1.45%		0.87%-1.20%
Expected term	4.5-4.75 years		4.75 years		4.56-4.75 years
Dividend yield		—		—		—
Expected volatility	53.15%-55.20%		55.23%-79.29%		76.86%-83.09%

Non-Employees [Member]

Assumptions Used to Value Options Granted

The weighted-average fair value of the options granted to non-employees during the year ended December 31, 2015 was $4.52 based on the following assumptions:

	2015
Risk free interest rate	1.47%-1.54%
Expected term	7 years
Dividend yield		—
Expected volatility	82.88%-83.09%