Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

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

The fair market value of the stock options at the date of grant was estimated using the Black-Scholes option-pricing model with the following weighted average assumptions for the years ended December 31:



	2016		2015
Expected life ⁽¹⁾	6 years, 2 months		6 years, 1 month
Interest rate	1.5	%	1.6	%
Dividend yield	—		—
Volatility ⁽²⁾	92.4	%	103.2	%


(1)	The Company uses the simplified method for estimating the stock option term.


(2)	For the year ended December 31, 2016, the Company estimated expected volatility based on the historical volatility of its own common stock on a stand-alone basis. For the year ended December 31, 2015, the Company estimated expected volatility based on the historical volatility of a peer group.

Summary of Stock Option Activity

The following table summarizes stock option activity for the years ended December 31, 2016 and 2015:



($ in thousands, except share and per share data)	Number of shares		Weighted- average exercise price		Weighted- average remaining contractual term (in years)	Aggregate intrinsic value
Outstanding at December 31, 2014	2,086,450		$	7.43	7 years, 2 months	$	—
Granted	1,352,114		4.48
Exercised	(56,250	)	4.53
Expired	(65,250	)	10.54
Forfeited	(182,970	)	5.91
Outstanding at December 31, 2015	3,134,094		$	6.23	8 years	$	1,630
Granted	1,585,400		1.60
Exercised	—		—
Expired	(35,482	)	7.93
Forfeited	(845,964	)	2.83
Outstanding at December 31, 2016 ⁽¹⁾	3,838,048		$	5.05	7 years, 2 months	$	—
Exercisable at December 31, 2016	2,179,198		$	7.11	5 years, 7 months	$	—


(1)	Includes both vested stock options as well as unvested stock options for which the requisite service period has not been rendered but that are expected to vest based on achievement of a service condition.