Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash flows from operating activities
Net (loss) income	$ (18,767)	$ (3,318)	$ 8,024
Adjustments to reconcile net (loss) income including non-controlling interests to net cash provided by operating activities:
Depreciation and amortization of property and equipment	27,446	18,940	15,958
Amortization of intangible assets	3,716	2,250	1,103
Impairment loss	959
Stock-based compensation	7,164	4,506	2,735
Excess tax benefits from stock-based compensation		(55)	1,818
Change in fair value of contingent consideration	(811)	(367)
Change in deferred income taxes	468	1,615	989
Changes in operating assets and liabilities, net of effect of acquisition:
Accounts receivable	(11,392)	(2,403)	(3,011)
Prepaid expenses and other assets	(1,935)	1,648	(347)
Accounts payable	(2,252)	(242)	(290)
Accrued expenses and other liabilities	4,739	(1,307)	(2,506)
Deferred revenue	11,872	(596)	123
Net cash provided by operating activities	21,207	20,671	24,596
Cash flows from investing activities
Decrease in restricted cash	545		435
Purchases of marketable securities	(27,163)	(33,430)	(70,185)
Proceeds from sales of marketable securities	58,511	42,026	28,627
Purchases of property and equipment	(70,945)	(29,500)	(18,000)
Payments for business acquisition, net of cash acquired	(147)	(19,459)	(3,185)
Other		(40)	(160)
Net cash used in investing activities	(39,199)	(40,403)	(62,468)
Cash flows from financing activities
Proceeds from Term Loan	3,500
Debt issuance costs	(711)
Proceeds from exercise of stock options	1,158	614	2,573
Repurchase and retirement of common stock		(4,848)
Excess tax benefits from stock-based compensation		55	372
Payments of capital leases and notes payable	(627)	(187)	(190)
Payments of acquired notes payable and financed liabilities		(6,079)
Payment of other acquisition related consideration	(1,255)
Payments of withholding tax on net issuance of restricted stock units	(1,922)	(15)
Payments to non-controlling interests	(623)	(608)	(678)
Net cash (used in) provided by financing activities	(480)	(11,068)	2,077
Effect of exchange rates on cash	(17)
Net decrease in cash and cash equivalents	(18,489)	(30,800)	(35,795)
Cash and cash equivalents at beginning of period	27,338	58,138	93,933
Cash and cash equivalents at end of period	8,849	27,338	58,138
Supplemental disclosure of cash flow information
Cash paid for interest	33	32	11
Cash (received) paid for taxes, net of refunds	(53)	96	737
Supplemental disclosure of non-cash investing and financing activities
Property and equipment costs in accounts payable, accrued expenses and other liabilities	11,647	10,283	2,607
Acquisition of equipment under capital leases	361
Assets acquired in business acquisition		39,794
Liabilities assumed in business acquisition		$ 16,151