Stock Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Schedule of stock-based compensation expense
Share-based Compensation			$ 2,622	$ 2,561
Allocated Share-based Compensation Expense	719	505	2,622	2,561
Restricted Stock Awards
Schedule of stock-based compensation expense
Share-based Compensation	563	171	1,875	1,179
Service-based restricted stock [Member] | Restricted Stock Awards
Schedule of stock-based compensation expense
Share-based Compensation	523	369	1,793	1,216
Performance-based restricted stock [Member] | Restricted Stock Awards
Schedule of stock-based compensation expense
Share-based Compensation	40	(198)	82	(37)
Cost of revenue
Schedule of stock-based compensation expense
Allocated Share-based Compensation Expense	228	163	762	543
Selling, General and Administrative Expenses
Schedule of stock-based compensation expense
Allocated Share-based Compensation Expense	332	213	1,337	1,586
Research and development [Member]
Schedule of stock-based compensation expense
Allocated Share-based Compensation Expense	$ 159	$ 129	$ 523	$ 432