Organization Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Organization Basis of Presentation and Summary of Significant Accounting Policies (Textual) [Abstract]
Max percentage of receivable from customer	10.00%	16.00%
Internal use software development cost capitalized	$ 1,100,000	$ 1,000,000	$ 1,100,000
Revenue recognition period, associated with service and maintenance agreement	1 year
Percentage of revenue recognized upon completion contract method	100.00%
Depreciation and amortization expense	13,900,000	10,000,000	8,700,000
Tax benefit realized upon settlement	50.00%
Advertising Expense	800,000	400,000	400,000
Stock-based compensation	20,913,000	15,539,000	10,579,000
Comcast [Member]
Organization Basis of Presentation and Summary of Significant Accounting Policies (Textual) [Abstract]
Entity-Wide Revenue, Major Customer, Percentage	11.00%	17.00%	16.00%
Euros [Member]
Organization Basis of Presentation and Summary of Significant Accounting Policies (Textual) [Abstract]
Forward exchange contract	6,900,000	3,300,000
Pounds [Member]
Organization Basis of Presentation and Summary of Significant Accounting Policies (Textual) [Abstract]
Forward exchange contract	5,700,000
Yen [Member]
Organization Basis of Presentation and Summary of Significant Accounting Policies (Textual) [Abstract]
Forward exchange contract		400,000
ILS [Member]
Organization Basis of Presentation and Summary of Significant Accounting Policies (Textual) [Abstract]
Forward exchange contract	$ 4,300,000