UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net (loss)	$ (46,112)	$ (61,013)
Adjustments to reconcile net (loss) to cash (used in) provided by operating activities
Stock-based compensation	48,831	38,397
(Gain) on capped call transactions	(827)	0
Deferred income taxes	(18,399)	(190)
Amortization of deferred commissions	16,061	14,179
Lease expense	7,819	6,718
Amortization of debt discount and issuance costs	6,033	0
Amortization of intangible assets and depreciation	10,134	12,268
Amortization of investments	0	623
Foreign currency transaction loss	1,691	1,607
Other non-cash	(1,374)	(40)
Change in operating assets and liabilities, net	(45,056)	(4,829)
Cash (used in) provided by operating activities	(21,199)	7,720
Investing activities
Purchases of investments	(1,769)	(10,497)
Proceeds from maturities and called investments	0	13,545
Sales of investments	1,424	29,965
Payments for acquisitions, net of cash acquired	0	10,921
Investment in property and equipment	(19,059)	(4,882)
Cash (used in) provided by investing activities	(19,404)	17,210
Financing activities
Proceeds from issuance of convertible senior notes	600,000	0
Purchase of capped calls related to convertible senior notes	(51,900)	0
Payment of debt issuance costs	(14,527)	0
Dividend payments to shareholders	(4,793)	(4,730)
Common stock repurchases	(43,487)	(39,637)
Cash provided by (used in) financing activities	485,293	(44,367)
Effect of exchange rate changes on cash and cash equivalents	(942)	515
Net increase (decrease) in cash and cash equivalents	443,748	(18,922)
Cash and cash equivalents, beginning of period	68,363	114,422
Cash and cash equivalents, end of period	$ 512,111	$ 95,500