Share-based Compensaton Allocated to Expense Captions (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
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 2,785	$ 2,393	$ 8,160	$ 6,113
Cost of Sales
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	320	272	857	707
Research and Development Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	266	194	725	632
Selling and Marketing Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1,123	816	3,158	2,121
General and Administrative Expense
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 1,076	$ 1,111	$ 3,420	$ 2,653
Equity Option
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	0.00%	0.00%	0.00%	0.00%