Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2017

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

Details of Fair Value Option Award

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:

	2017		2016
Expected life (1)	5 years, 11 months		6 years, 2 months
Interest rate	1.9	%	1.5	%
Dividend yield	—		—
Volatility	88.7	%	92.4	%

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

Summary of Stock Option Activity

The following table summarizes stock option activity for the years ended December 31, 2017 and 2016:

($ 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, 2015	1,044,723		$	18.69	8 years	$	1,630
Granted	528,479		4.80
Expired	(11,840	)	11.84
Forfeited	(281,983	)	8.49
Outstanding at December 31, 2016	1,279,379		$	15.16	7 years, 2 months	$	—
Granted	295,000		2.88
Expired	(211,773	)	21.35
Forfeited	(273,093	)	9.50
Outstanding at December 31, 2017 (1)	1,089,513		$	12.06	7 years, 3 months	$	—
Exercisable at December 31, 2017	665,334		$	17.48	6 years, 1 month	$	—

(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.