Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities:
Net loss	$ (97,135)	$ (382,957)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation and amortization	52,407	37,452
Amortization of premiums on investments	1,706	2,799
Amortization of deferred commissions	50,587	36,957
Amortization of debt discount and issuance costs	20,015	16,357
Stock-based compensation	188,009	153,373
Deferred income tax	(4,751)	(6,426)
Other	(3,720)	532
Changes in operating assets and liabilities, net of effect of business combinations:
Accounts receivable	51,039	6,967
Deferred commissions	(61,287)	(48,397)
Prepaid expenses and other assets	(11,945)	(10,001)
Accounts payable	(7,860)	(272)
Deferred revenue	145,662	104,399
Accrued expenses and other liabilities	(6,578)	19,733
Net cash provided by (used in) operating activities	316,149	(69,484)
Cash flows from investing activities:
Purchases of property and equipment	(69,103)	(52,929)
Business combinations, net of cash acquired	(21,537)	(34,297)
Purchases of other intangibles	(6,170)	(10,750)
Purchases of investments	(354,690)	(180,365)
Purchases of strategic investments	(3,900)	0
Sales of investments	77,968	92,885
Maturities of investments	221,949	158,520
Restricted cash	(830)	(611)
Net cash used in investing activities	(156,313)	(27,547)
Cash flows from financing activities:
Net proceeds from borrowings on convertible senior notes	772,127	0
Proceeds from issuance of warrants	54,071	0
Purchases of convertible note hedges	(128,017)	0
Proceeds from employee stock plans	40,892	34,151
Taxes paid related to net share settlement of equity awards	(87,349)	(59,786)
Repurchases of common stock from stockholders	(55,000)	0
Payments on financing obligations	(2,560)	(223)
Net cash provided by (used in) financing activities	594,164	(25,858)
Foreign currency effect on cash and cash equivalents	18,219	(303)
Net increase (decrease) in cash and cash equivalents	772,219	(123,192)
Cash and cash equivalents at beginning of period	401,238	412,305
Cash and cash equivalents at end of period	1,173,457	289,113
Non-cash investing and financing activities:
Property and equipment included in accounts payable and accrued expenses	16,030	14,058
Financing obligation for purchases of other intangibles	$ 2,110	$ 4,100