Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Operating activities:
Net income (loss)	$ (72,741)	$ (70,312)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	32,158	42,349
Stock-based expense	80,982	99,803
(Gain) loss from sales of investments, assets and other, net	160	(6,283)
Tax benefits (costs) from stock-based awards		90
Excess tax benefits (costs) from stock-based awards		(90)
Accretion and amortization on marketable securities	322	4,941
Deferred income taxes	(2,734)	(9,151)
Impairment of intangible assets	20,677
Changes in operating assets and liabilities:
Accounts receivable, net	8,743	2,544
Income tax receivable	1,711	(1,712)
Other assets	(2,519)	(11,860)
Accounts payable	(10,171)	12,226
Deferred revenue	2,121	(61,097)
Other liabilities	(26,436)	(49,360)
Net cash provided by (used in) operating activities	32,273	(47,912)
Investing activities:
Purchases of marketable securities		(101,091)
Sales and maturities of marketable securities	240,337	702,017
Acquisition of property and equipment	(6,621)	(6,847)
Business acquisitions, net of cash acquired	(33,630)	(20,023)
Proceeds from sale of property and equipment	3,035	750
Proceeds from sale of equity method investment		10,507
Net cash provided by (used in) investing activities	203,121	585,313
Financing activities:
Taxes paid related to net share settlement of equity awards	(2,163)	(1,866)
Repurchases of common stock	(112,392)
Proceeds from employee stock purchase plan and exercise of stock options	5,570	7,292
Excess tax benefits (costs) from stock-based awards		90
Acquisition-related contingent consideration payment		(10,790)
Net cash provided by (used in) financing activities	(108,985)	(5,274)
Effect of exchange rate changes on cash and cash equivalents	(2,307)	(410)
Net increase (decrease) in cash and cash equivalents	124,102	531,717
Cash and cash equivalents, beginning of period	742,217	131,303
Cash and cash equivalents, end of period	$ 866,319	$ 663,020