Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities:
Net loss	$ (149,387)	$ (102,107)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization	4,283	2,010
Equity-based compensation	29,848	20,857
Loss from equity method investment		2,037
Other expense, non-cash	889
Changes in:
Accounts receivable	66	(233)
Prepaid expenses and other assets	23,595	(1,399)
Accounts payable and accrued expenses	13,216	(849)
Deferred revenue	(201)	(50)
Operating lease assets and liabilities	(111)	(391)
Other liabilities, net	(3,652)	6
Net cash used in operating activities	(81,454)	(80,119)
Investing activities:
Purchase of property and equipment	(6,596)	(3,271)
Net cash used in investing activities	(6,596)	(3,271)
Financing activities:
Proceeds from issuance of common shares, net of issuance costs	83,021	52,294
Proceeds from exercise of options, net of issuance costs	7,616	3,086
Net cash provided by financing activities	90,637	55,380
Effect of exchange rate changes on cash	(28)	(2)
Increase (decrease) in cash	2,559	(28,012)
Cash, cash equivalents and restricted cash, beginning of period	948,812	459,812
Cash, cash equivalents and restricted cash, end of period	951,371	431,800
Supplemental disclosure of non-cash investing and financing activities
Property and equipment purchases in accounts payable and accrued expenses	2,585	702
Equity issuance costs in accounts payable and accrued expenses	$ 1,009	$ 477