Stock-Based Compensation (Stock-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of stock-based compensation expense
Stock-based compensation	$ 1,055	$ 626	$ 3,630	$ 3,361
Stock options [Member]
Schedule of stock-based compensation expense
Stock-based compensation	247	397	843	1,538
Restricted stock units [Member]
Schedule of stock-based compensation expense
Stock-based compensation	722	527	2,383	1,823
Performance stock units [Member]
Schedule of stock-based compensation expense
Stock-based compensation	86	(298)	404	0
Research and development [Member]
Schedule of stock-based compensation expense
Stock-based compensation	227	97	734	989
Selling, general and administrative [Member]
Schedule of stock-based compensation expense
Stock-based compensation	$ 828	$ 529	$ 2,896	$ 2,372