Balance Sheet Components (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Cash and cash equivalents
Cash	$ 12,690	$ 3,614
Cash equivalents:
Money market funds	106,999	121,466
Certificates of deposit	25	3,219
Total cash equivalents	107,024	124,685
Cash and cash equivalents	119,714	128,299	121,882	44,247
Accounts Receivable
Accounts receivable	29,943	27,275
Allowance for doubtful accounts	(295)	(329)
Accounts receivable, net	29,648	26,946
Property and equipment, net
Total property and equipment	24,547	19,595
Less accumulated depreciation	(9,058)	(5,739)
Property and equipment, net	15,489	13,856
Computer equipment
Property and equipment, net
Total property and equipment	16,035	12,919
Software
Property and equipment, net
Total property and equipment	2,360	2,314
Office furniture
Property and equipment, net
Total property and equipment	1,576	1,318
Leasehold improvements
Property and equipment, net
Total property and equipment	3,130	2,993
Construction in progress
Property and equipment, net
Total property and equipment	$ 1,446	$ 51