Stock Plans (Details 1) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Schedule of stock-based compensation expense
Share-based Compensation			$ 1,850	$ 1,921
Total stock-based compensation expense	$ 1,011	$ 1,166	1,850	1,921
Restricted stock awards
Schedule of stock-based compensation expense
Share-based Compensation	529	723	955	1,162
Restricted stock unit awards
Schedule of stock-based compensation expense
Share-based Compensation	212	54	386	54
Restricted stock unit awards | Market-condition restricted stock units
Schedule of stock-based compensation expense
Share-based Compensation	34	22	67	22
Service-based restricted stock awards | Restricted stock awards
Schedule of stock-based compensation expense
Share-based Compensation	579	716	999	1,149
Service-based restricted stock awards | Restricted stock unit awards
Schedule of stock-based compensation expense
Share-based Compensation	205	32	287	32
Performance-based restricted stock awards | Restricted stock awards
Schedule of stock-based compensation expense
Share-based Compensation	(50)	7	(44)	13
Performance-based restricted stock awards | Restricted stock unit awards
Schedule of stock-based compensation expense
Share-based Compensation	(27)	0	32	0
Cost of revenue
Schedule of stock-based compensation expense
Total stock-based compensation expense	147	190	353	442
Selling, general and administrative
Schedule of stock-based compensation expense
Total stock-based compensation expense	657	733	1,023	988
Research and development
Schedule of stock-based compensation expense
Total stock-based compensation expense	$ 207	$ 243	$ 474	$ 491