CONSOLIDATED AND CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Cash flows from operating activities
Net loss	$ (654,362)	$ (360,235)
Adjustments to reconcile net loss to net cash used in operating activities
Depreciation and amortization	134,172	87,426
Equity-based compensation	162,014	88,148
Amortization of discount and issuance costs on convertible notes	40,737	13,699
Other non-cash adjustments	(1,659)	177
Changes in operating assets and liabilities:
Accounts receivable	(25,309)	(3,157)
Inventories	(22,716)	(7,757)
Prepaid expenses and other current assets	(29,648)	(37,376)
Accounts payable and accrued expenses	215,786	187,733
Unearned revenue and other liabilities	22,382	80,509
Other assets	(1,920)	(6,836)
Net cash (used in) provided by operating activities	(160,523)	42,331
Cash flows from investing activities
Sale and maturities of short-term investments	115,468	45,955
Purchase of property and equipment	(183,968)	(110,504)
Site and software development costs	(94,697)	(45,769)
Other investing activities	(15,977)	(399)
Net cash used in investing activities	(179,174)	(110,717)
Cash flows from financing activities
Proceeds from issuance of convertible notes, net of issuance costs	935,146	0
Premiums paid for capped call confirmations	(145,728)	0
Taxes paid related to net share settlement of equity awards	(1,510)	(1,097)
Deferred financing costs	(791)	0
Net proceeds from exercise of stock options	90	104
Net cash provided by (used in) financing activities	787,207	(993)
Effect of exchange rate changes on cash and cash equivalents	(1,586)	(945)
Net increase (decrease) in cash and cash equivalents	445,924	(70,324)
Cash and cash equivalents
Beginning of period	849,461	558,960
End of period	1,295,385	488,636
Supplemental cash flow information
Cash paid for interest on long-term debt	4,528	1,554
Purchase of property and equipment included in accounts payable and accrued expenses and in other liabilities	34,028	10,520
Construction costs capitalized under finance lease obligation and other leases	$ 0	$ 64,408