Geographical Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Revenue and long-lived assets by geographical segments
Revenues	$ 93,818	$ 84,594	$ 283,003	$ 215,956
United States
Revenue and long-lived assets by geographical segments
Revenues	69,984	64,615	208,042	187,960
North America (Excluding U.S.)
Revenue and long-lived assets by geographical segments
Revenues	5,677	5,620	17,780	10,882
Europe, Middle East and Africa
Revenue and long-lived assets by geographical segments
Revenues	10,413	9,099	37,320	11,144
Asia Pacific
Revenue and long-lived assets by geographical segments
Revenues	5,241	3,584	15,039	3,921
Latin America
Revenue and long-lived assets by geographical segments
Revenues	$ 2,503	$ 1,676	$ 4,822	$ 2,049