Stock Compensation (Schedule Of Shares Available For Grant) (Details)	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares	9,374,000
Available for Grant	3,762,000	2,343,000
1996 Discounted Employee Stock Purchase Plan, As Amended [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares	1,900,000
Available for Grant	847,000	918,000
2002 Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares	974,000
Available for Grant		7,000
2004 Employee Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares	2,100,000
Available for Grant	41,000	293,000
2008 Non-Employee Directors Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares	300,000
Available for Grant	27,000	88,000
2009 Employee Stock Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorized Shares	4,100,000
Available for Grant	2,847,000	1,037,000