CONSOLIDATED AND CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net loss	$ (285,865)	$ (200,389)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	66,843	39,583
Equity-based compensation	59,449	47,060
Amortization of discount and issuance costs on convertible notes	19,527	12,456
Other non-cash adjustments	(633)	(1,374)
Changes in operating assets and liabilities:
Accounts receivable, net	(16,216)	(11,570)
Inventories	5,023	2,427
Prepaid expenses and other current assets	7,802	(10,535)
Accounts payable and accrued expenses	(114,623)	46,631
Unearned revenue and other liabilities	2,379	(4,933)
Other assets	24	(704)
Net cash used in operating activities	(256,290)	(81,348)
Cash flows from investing activities:
Sale and maturities of short- and long-term investments	294,810	37,936
Purchase of property and equipment	(59,964)	(60,626)
Site and software development costs	(38,369)	(24,843)
Other investing activities, net	(124)	2,838
Net cash provided by (used in) investing activities	196,353	(44,695)
Cash flows from financing activities:
Proceeds from borrowings	100,000	0
Taxes paid related to net share settlement of equity awards	0	(165)
Deferred financing costs	0	(791)
Net proceeds from exercise of stock options	125	67
Net cash provided by (used in) financing activities	100,125	(889)
Effect of exchange rate changes on cash and cash equivalents	1,540	(169)
Net increase (decrease) in cash and cash equivalents	41,728	(127,101)
Cash and cash equivalents:
Beginning of period	582,753	849,461
End of period	624,481	722,360
Supplemental cash flow information:
Cash paid for interest on long-term debt	5,447	809
Purchase of property and equipment included in accounts payable and accrued expenses and in other liabilities	$ 45,495	$ 3,143