Stock Options And Employee Stock Purchase Plan (Allocation Of Share-Based Compensation Expense) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Allocated Share-based Compensation Expense	$ 1,963	$ 2,335	$ 4,347	$ 4,683
Cost Of Revenues [Member]
Allocated Share-based Compensation Expense	27	205	181	419
Sales And Marketing [Member]
Allocated Share-based Compensation Expense	426	432	917	850
Research, Development And Engineering [Member]
Allocated Share-based Compensation Expense	222	102	362	208
General And Administrative [Member]
Allocated Share-based Compensation Expense	$ 1,288	$ 1,596	$ 2,887	$ 3,206