Stock Options and Stock-Based Employee Compensation (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
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)			100.00%	110.00%
Weighted-average expected term			5 years 4 months 24 days	4 years 8 months 12 days
Weighted-average risk-free interest rate (in hundredths)			1.60%	0.74%
Expected dividends (in hundredths)			0.00%	0.00%
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee stock-based compensation	$ 781	$ 607	$ 1,485	$ 963
Research and Development [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee stock-based compensation	299	200	547	341
Selling, General & Administrative [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Employee stock-based compensation	$ 482	$ 407	$ 938	$ 622