Segment Reporting and Significant Customer Information - Revenue for Individual Countries that Exceed 10% of Total Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue, Major Customer [Line Items]
Total revenues	$ 33,728	$ 36,307	$ 109,665	$ 118,949
United States of America
Revenue, Major Customer [Line Items]
Total revenues	19,465	16,711	65,391	65,141
United Kingdom
Revenue, Major Customer [Line Items]
Total revenues	6,686	7,023	21,413	23,763
Rest of the world
Revenue, Major Customer [Line Items]
Total revenues	$ 7,577	$ 12,573	$ 22,861	$ 30,045