Stock-Based Compensation (Employee Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 4,955	$ 4,713	$ 15,257	$ 14,102
Cost of product revenues
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	187	155	548	501
Research and development
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	1,378	1,108	4,209	3,596
Selling and marketing
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	1,325	1,359	4,315	4,234
General and administrative
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 2,065	$ 2,091	$ 6,185	$ 5,771