Stock Plans (Details 1) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Schedule of stock-based compensation expense
Share-based Compensation			$ 2,906	$ 2,934
Total stock-based compensation expense	$ 1,055	$ 1,011	2,906	2,934
Restricted stock awards
Schedule of stock-based compensation expense
Share-based Compensation	546	703	1,501	1,854
Restricted stock unit awards
Schedule of stock-based compensation expense
Share-based Compensation	203	85	590	139
Restricted stock unit awards | Market-condition restricted stock units
Schedule of stock-based compensation expense
Share-based Compensation	34	34	102	56
Service-based restricted stock awards | Restricted stock awards
Schedule of stock-based compensation expense
Share-based Compensation	546	696	1,545	1,834
Service-based restricted stock awards | Restricted stock unit awards
Schedule of stock-based compensation expense
Share-based Compensation	229	51	516	83
Performance-based restricted stock awards | Restricted stock awards
Schedule of stock-based compensation expense
Share-based Compensation	0	7	(44)	20
Performance-based restricted stock awards | Restricted stock unit awards
Schedule of stock-based compensation expense
Share-based Compensation	(60)	0	(28)	0
Cost of revenue
Schedule of stock-based compensation expense
Total stock-based compensation expense	186	145	539	587
Selling, general and administrative
Schedule of stock-based compensation expense
Total stock-based compensation expense	708	716	1,732	1,705
Research and development
Schedule of stock-based compensation expense
Total stock-based compensation expense	$ 161	$ 150	$ 635	$ 642