Other Balance Sheet Amounts - Property and Equipment (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Property and Equipment [Details]
Property and equipment, gross	$ 23,177,000	$ 13,513,000
Less: accumulated depreciation and amortization	(8,741,000)	(5,566,000)
Total property and equipment, net	14,436,000	7,947,000
Depreciation expense	3,200,000	2,500,000	1,800,000
Computer equipment and software
Property and Equipment [Details]
Property and equipment, gross	15,768,000	9,976,000
Capital leased assets, gross	2,800,000	4,600,000
Capital leased assets, accumulated depreciation	2,000,000	2,800,000
Capital leased assets, depreciation expense	900,000	1,100,000	900,000
Computer equipment and software | Minimum
Property and Equipment [Details]
Property, plant and equipment, useful life	2 years
Computer equipment and software | Maximum
Property and Equipment [Details]
Property, plant and equipment, useful life	5 years
Furniture and fixtures
Property and Equipment [Details]
Property and equipment, gross	2,265,000	869,000
Property, plant and equipment, useful life	7 years
Leasehold improvements
Property and Equipment [Details]
Property and equipment, gross	4,190,000	1,520,000
Leasehold improvements | Minimum
Property and Equipment [Details]
Property, plant and equipment, useful life	2 years
Leasehold improvements | Maximum
Property and Equipment [Details]
Property, plant and equipment, useful life	6 years
Renovation in progress
Property and Equipment [Details]
Property and equipment, gross	$ 954,000	$ 1,148,000