Intangible Assets (Schedule Of Intangible Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 12,656	$ 12,597
Accumulated Amortization	(6,413)	(6,108)
Net Carrying Value	6,243	6,489
Weighted Average Useful Life (in Years)	4 years 6 months	4 years 10 months 24 days
Developed Technology [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	7,490	7,490
Accumulated Amortization	(3,701)	(3,480)
Net Carrying Value	3,789	4,010
Weighted Average Useful Life (in Years)	4 years 3 months 18 days	4 years 7 months 6 days
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	3,267	3,267
Accumulated Amortization	(1,917)	(1,853)
Net Carrying Value	1,350	1,414
Weighted Average Useful Life (in Years)	5 years 3 months 18 days	5 years 9 months 18 days
Other Intangibles [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	1,742	1,840
Accumulated Amortization	(795)	(775)
Net Carrying Value	947	1,065
Weighted Average Useful Life (in Years)	4 years 6 months	5 years 2 months 12 days
Software Development Costs [Member]
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	157
Net Carrying Value	$ 157