Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of stock-based compensation expense
Stock-based compensation	$ 1,223	$ 1,055	$ 3,759	$ 3,630
Stock options [Member]
Schedule of stock-based compensation expense
Stock-based compensation	281	247	798	843
Restricted stock units [Member]
Schedule of stock-based compensation expense
Stock-based compensation	566	722	2,020	2,383
Performance stock units [Member]
Schedule of stock-based compensation expense
Stock-based compensation	376	86	941	404
Research and development [Member]
Schedule of stock-based compensation expense
Stock-based compensation	181	227	710	734
Selling, general and administrative [Member]
Schedule of stock-based compensation expense
Stock-based compensation	$ 1,042	$ 828	$ 3,049	$ 2,896