Information About Revenue By Geographic Area (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Geographic revenue based on customer location
Revenue	$ 56,809	$ 40,625	$ 107,926	$ 78,199
North America
Geographic revenue based on customer location
Revenue	20,830	14,496	39,201	27,610
United States | Total revenue | Geographic concentration
Geographic revenue based on customer location
Concentration risk percentage	33.00%	32.00%	32.00%	32.00%
Europe
Geographic revenue based on customer location
Revenue	20,129	15,080	39,181	29,578
Rest of the world
Geographic revenue based on customer location
Revenue	$ 15,850	$ 11,049	$ 29,544	$ 21,011