Stock Options and Stock-Based Employee Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Stock Options and Stock-Based Employee Compensation [Abstract]
Weighted-average vesting period of stock options			3 years
Weighted-average assumptions used in estimating fair value of stock options [Abstract]
Weighted average expected volatility (in hundredths)			83.00%	100.00%
Weighted average expected term			5 years 7 months 6 days	5 years 4 months 24 days
Weighted average risk-free interest rate (in hundredths)			1.50%	1.60%
Expected dividends (in hundredths)			0.00%	0.00%
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee stock-based compensation	$ 335	$ 781	$ 934	$ 1,485
Research & Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee stock-based compensation	146	299	359	547
Selling, General & Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee stock-based compensation	$ 189	$ 482	$ 575	$ 938