Segment Information (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended					36 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2010 Customer Concentration Risk [Member] Revenue [Member] contracts resellers	Dec. 31, 2009 Customer Concentration Risk [Member] Revenue [Member] contracts resellers	Dec. 31, 2011 Customer Concentration Risk [Member] Revenue [Member] contracts resellers
Concentration Risk [Line Items]
Percentage of international revenues accounting for of the Company's net revenues	43.20%	42.70%	43.60%
Percentage of one distributor accounted for of the Company's total net revenues	17.00%	17.00%	14.00%
Number of contracts accounting for over 10% of total net revenues				0	0	0
Number of resellers accounted for over 10% of total net revenues				0	0	0
Shipments from United States to international customers	$ 106.0	$ 95.0	$ 74.5