Stock-Based Compensation (Employee Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 5,197	$ 4,847	$ 10,302	$ 9,389
Cost of product revenues
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	170	152	361	312
Research and development
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	1,443	1,269	2,831	2,522
Selling and marketing
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	1,478	1,437	2,989	2,875
General and administrative
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 2,106	$ 1,989	$ 4,121	$ 3,680