Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2018		Jun. 30, 2017	[2]
Cash flows from operating activities:
Net loss		$ (42,124)		$ (77,318)	[1]
Adjustments to reconcile net loss to net cash provided by operating activities:
Depreciation and amortization		68,618		52,407
Amortization of deferred commissions		64,304		43,086
Amortization of debt discount and issuance costs		32,562		20,015
Stock-based compensation		256,901		187,935
Deferred income tax		(30,926)		(4,751)
Gain on marketable equity securities		(19,257)		0
Repayments of convertible senior notes attributable to debt discount		(87,557)		0
Other		(1,707)		(2,014)
Changes in operating assets and liabilities, net of effect of business combinations:
Accounts receivable		65,940		55,186
Deferred commissions		(92,995)		(69,947)
Prepaid expenses and other assets		2,040		(3,606)
Accounts payable		(2,632)		(7,860)
Deferred revenue		131,089		133,416
Accrued expenses and other liabilities		31,720		(10,216)
Net cash provided by operating activities		375,976		316,333
Cash flows from investing activities:
Purchases of property and equipment		(88,362)		(69,103)
Business combinations, net of cash and restricted cash acquired		(24,940)		(21,537)
Purchases of other intangibles		(10,850)		(6,170)
Purchases of investments		(379,913)		(358,590)
Sales of investments		39,975		77,968
Maturities of investments		453,156		221,949
Net cash used in investing activities		(10,934)	[3]	(155,483)
Cash flows from financing activities:
Net proceeds from borrowings on convertible senior notes		0		772,127
Repayments of convertible senior notes attributable to principal		(271,185)		0
Proceeds from issuance of warrants		0		54,071
Purchases of convertible note hedges		0		(128,017)
Repurchases and retirement of common stock		0		(55,000)
Proceeds from employee stock plans		61,419		40,892
Taxes paid related to net share settlement of equity awards		(154,531)		(87,349)
Payments on financing obligations		(576)		(2,560)
Net cash (used in) provided by financing activities		(364,873)		594,164
Foreign currency effect on cash, cash equivalents and restricted cash	[3]	(7,505)		18,040
Net (decrease) increase in cash, cash equivalents and restricted cash	[3]	(7,336)		773,054
Cash, cash equivalents and restricted cash at beginning of period	[3]	727,829		401,932
Cash, cash equivalents and restricted cash at end of period	[3]	720,493		1,174,986
Cash, cash equivalents and restricted cash at end of period:
Total cash, cash equivalents and restricted cash shown in the condensed consolidated statements of cash flows	[3]	727,829		401,932
Non-cash investing and financing activities:
Benefit from 2018 Note Hedges		467,176		0
Property and equipment included in accounts payable and accrued expenses		25,027		16,030
Financing obligation for purchases of other intangibles		$ 0		$ 2,110

[1] As adjusted to reflect the impact of the full retrospective adoption of Topic 606. See Note 2 for further details

[2] As adjusted to reflect the impact of the full retrospective adoption of Topic 606. See Note 2 for further details.

[3] During the three months ended December 31, 2017, we adopted Accounting Standards Update 2016-18, “Statement of Cash Flows (Topic 230): Restricted Cash,” which requires that amounts generally described as restricted cash or restricted cash equivalents be included with cash and cash equivalents when reconciling the beginning-of-period and end-of-period total amounts shown on the statement of cash flows. Accordingly, we have recast our prior period condensed consolidated statement of cash flows to conform to the current presentation. The impact of the adoption for the six months ended June 30, 2017 is not material.