CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net loss	$ (23,161)	$ (21,721)
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization	11,879	10,778
Stock-based compensation	25,513	27,727
Accretion of debt discount		116
Amortization of debt issuance costs	134	57
Loss on disposal of property and equipment	2	9
Gain on sale of a right to use a web domain name	(4,800)
Allowance for doubtful accounts	46	138
Deferred income taxes	(456)	807
Change in fair value of contingent consideration	1,484	(2,806)
Changes in operating assets and liabilities:
Accounts receivable	(2,295)	(5,390)
Prepaid expenses and other current assets	(2,790)	(4,653)
Accounts payable and other current liabilities	2,056	1,729
Accrued compensation and benefits	(3,279)	(1,068)
Deferred revenues	1,190	358
Other	5	(742)
Net cash provided by operating activities	5,528	5,339
Cash flows from investing activities:
Purchases of property and equipment	(9,406)	(6,621)
Acquisitions, net of acquired cash		(11,641)
Purchase of intangible assets	(283)	(37)
Proceeds from sale of a right to use a web domain name	4,800
Net cash used in investing activities	(4,889)	(18,299)
Cash flows from financing activities:
Proceeds from issuance of common stock	4,656	4,083
Repurchases of common stock	(8,852)
Proceeds from initial public offering, net of offering costs		176,525
Exercise of warrant		1,610
Repayment of debt obligations, related party		(15,000)
Repayment of debt obligations	(7,500)
Principal payments on capital lease obligations	(46)	(43)
Net cash (used in) provided by financing activities	(11,742)	167,175
Effect of exchange rates on cash and cash equivalents	16	10
Net (decrease) increase in cash and cash equivalents	(11,087)	154,225
Cash and cash equivalents at beginning of period	201,075	38,972
Cash and cash equivalents at end of period	$ 189,988	$ 193,197