Stock-Based Compensation (Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Schedule of stock-based compensation expense
Stock-based compensation	$ 1,230	$ 1,223	$ 3,861	$ 3,759
Stock options [Member]
Schedule of stock-based compensation expense
Stock-based compensation	249	281	820	798
RSAs and RSUs [Member]
Schedule of stock-based compensation expense
Stock-based compensation	445	566	1,580	2,020
Performance stock units [Member]
Schedule of stock-based compensation expense
Stock-based compensation	536	376	1,461	941
Research and development [Member]
Schedule of stock-based compensation expense
Stock-based compensation	246	181	688	710
Selling, General and Administrative Expenses [Member]
Schedule of stock-based compensation expense
Stock-based compensation	$ 984	$ 1,042	$ 3,173	$ 3,049