Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash flows from operating activities
Net (loss) income	$ (3,143)	$ 8,024	$ 6,937
Adjustments to reconcile net (loss) income including non-controlling interests to net cash provided by operating activities:
Depreciation and amortization of property and equipment	18,940	15,958	12,301
Amortization of intangible assets	2,250	1,103	1,655
Stock-based compensation	4,506	2,735	3,450
Forgiveness on note receivable from stockholder			103
Excess tax benefits from stock-based compensation	(55)	1,818
Change in fair value of preferred stock warrants			132
Change in fair value of contingent consideration	(367)
Change in deferred income taxes	1,440	989	2,828
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(2,403)	(3,011)	734
Prepaid expenses and other assets	1,648	(347)	357
Accounts payable	(242)	(290)	(1,236)
Accrued expenses and other liabilities	(1,307)	(2,506)	(83)
Deferred revenue	(596)	123	2,351
Net cash provided by operating activities	20,671	24,596	29,529
Cash flows from investing activities
Decrease in restricted cash		435	536
Purchases of marketable securities	(33,430)	(70,185)
Proceeds from sales of marketable securities	42,026	28,627	9,373
Purchases of property and equipment	(29,500)	(18,000)	(16,917)
Payments for patents, trademarks and domain	(40)	(146)	(156)
Payments for business acquisitions, net of cash acquired	(19,459)	(3,185)
Other		(14)	(171)
Net cash used in investing activities	(40,403)	(62,468)	(7,335)
Cash flows from financing activities
Proceeds from issuance of common stock upon initial public offering			48,297
Offering costs			(2,586)
Proceeds from exercise of stock options	614	2,573	1,028
Repurchase and retirement of common stock	(4,848)
Excess tax benefits from stock-based compensation	55	372	246
Payments of capital leases and notes payable	(187)	(190)	(420)
Payments of acquired notes payable and financed liabilities	(6,079)
Payments of withholding tax on net exercise of restricted stock units	(15)
Payments to non-controlling interests	(608)	(678)	(547)
Net cash (used in) provided by financing activities	(11,068)	2,077	46,018
Net (decrease) increase in cash and cash equivalents	(30,800)	(35,795)	68,212
Cash and cash equivalents at beginning of year	58,138	93,933	25,721
Cash and cash equivalents at end of year	27,338	58,138	93,933
Supplemental disclosure of cash flow information
Cash paid for interest	32	11	11
Cash paid for taxes	96	737	1,357
Supplemental disclosure of non-cash investing and financing activities
Conversion of convertible preferred stock into common stock			124,602
Retirement of treasury stock			4,575
Property and equipment costs in accounts payable, accrued expenses and other liabilities	10,283	2,607	1,995
Accretion of convertible preferred stock			1,633
Exercise and conversion of preferred stock warrants into common stock			272
Acquisition of software, equipment and software maintenance services under capital leases			402
Assets acquired in business acquisition	39,794
Liabilities assumed in business acquisition	$ 16,151