Stock-Based Compensation (Employee Stock-Based Compensation Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 18,303	$ 16,005	$ 16,538
Stock Options | Unvested Stock Options
Employee Stock Based Compensation Expense
Unrecognized compensation expense (in dollars)	$ 8,800
Weighted-average period of recognition of unrecognized stock-based compensation expense	2 years 7 months 6 days
RSUs
Employee Stock Based Compensation Expense
Unrecognized compensation expense (in dollars)	$ 15,100
Weighted-average period of recognition of unrecognized stock-based compensation expense	1 year 9 months 18 days
Cost of product revenues
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 590	525	497
Research and development
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	4,934	4,228	4,143
Selling and marketing
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	5,551	4,526	4,822
General and administrative
Employee Stock Based Compensation Expense
Stock-based compensation expense (in dollars)	$ 7,228	$ 6,726	$ 7,076