Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities
Net loss	$ (220,438)	$ (148,874)	$ (43,610)
Adjustments to reconcile net loss to net cash provided by operating activities, net of amounts assumed in connection with acquisitions:
Depreciation and amortization	100,590	75,386	35,624
Share-based compensation expense	106,918	105,214	34,085
Loss on debt extinguishment	22,757
Amortization of discount and issuance costs on 2021 Notes	883
Restructuring costs		19,001
Release of valuation allowance on certain deferred tax assets	(1,370)	(2,853)
Loss on disposal of property and equipment	3,689	1,384	505
Loss (gain) on divestiture of businesses, net	(1,360)	3,899
Bad debt expense	2,681	3,235	2,529
Deferred rent	1,730	2,553	4,415
Amortization of bond premium	1,489	2,487	3,506
Impairment of certain acquired intangible assets			3,259
Changes in operating assets and liabilities:
Accounts receivable	(13,324)	(1,051)	(5,979)
Prepaid expenses and other assets	(13,260)	(761)	(5,084)
Accounts payable	856	(11,158)	4,634
Accrued expenses and other current liabilities	(5,065)	(18,384)	6,282
Accrued compensation and benefits	12,463	(4,020)	2,295
Deferred revenue	7,794	(2,434)	3,058
Other long-term liabilities	1,612	(965)
Net cash provided by operating activities	8,645	22,659	45,519
Investing activities
Proceeds from maturities of investments	197,407	335,443	174,949
Purchases of investments	(175,210)	(307,658)	(272,644)
Proceeds from sales of investments	4,963	8,260
Decrease in restricted cash, net of amounts assumed in connection with an acquisition	1,962	3,931
Purchases of property and equipment	(62,060)	(52,685)	(31,515)
Purchases of intangible assets	(9,662)	(15,423)	(12,727)
Purchase of cost method investment	(10,000)
Proceeds from divestiture of businesses	3,200	23,359
Cash acquired in acquisition, net		173,406
Cash paid for acquisitions, net	(16,319)	(104,192)	(3,500)
Net cash provided by (used in) investing activities	(65,719)	64,441	(145,437)
Financing activities
Proceeds from issuance of 2021 Notes, net of issuance costs	447,784
Premiums paid for Capped Call Confirmations	(36,616)
Partial repurchase of 2020 Notes	(370,235)
Proceeds from exercise of stock options	31,211	24,423	23,923
Value of equity awards withheld for tax liability	(616)	(8,150)
Net cash provided by financing activities	71,528	16,273	23,923
Net increase (decrease) in cash and cash equivalents during period	14,454	103,373	(75,995)
Cash and cash equivalents at beginning of period	229,138	125,765	201,760
Cash and cash equivalents at end of period	243,592	229,138	125,765
Supplemental disclosures of cash flow information
Cash paid for interest	6,325	6,325
Noncash transactions:
Value of Class A common stock issued in connection with an acquisition		1,883,728
Capitalized share-based compensation	10,061	10,319	6,585
Write-off of fully depreciated property and equipment	14,564	$ 26,242	$ 4,749
Write-off of fully amortized intangible assets	$ 9,293