Segment and Geographical Information - Additional Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013 Location	Sep. 30, 2012 Location	Sep. 30, 2013 Segment Location	Sep. 30, 2012 Location
Revenues from External Customers and Long-Lived Assets [Line Items]
Number of operating segments			1
Number of reportable business segment			1
Number of geographic regions	2	2	2	2
Revenue	$ 50,196	$ 46,839	$ 151,659	$ 143,535
Japan [Member]
Revenues from External Customers and Long-Lived Assets [Line Items]
Minimum percentage of revenues		10.00%		10.00%
Revenue	$ 7,300	$ 7,500	$ 20,800	$ 21,000