Summary of Significant Accounting Policies and Basis of Presentation - Property and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Depreciation expense	$ 5.3	$ 6.0	$ 6.8
Computer laptops [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Computer desktops [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	4 years
IT server, storage and network equipment [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Furniture and fixtures [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	5 years
Purchased software [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	3 years
Leasehold improvements [Member]
Property, Plant and Equipment [Line Items]
Property and equipment, estimated useful life	10 years