Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities:
Net loss	$ (113,163)	$ (69,731)
Reconciliation of net loss to net cash used in operating activities:
Depreciation and amortization	2,715	2,091
Equity-based compensation	22,092	14,151
Other income, non-cash	2,064	890
Changes in:
Accounts receivable	(6)	(25,018)
Prepaid expenses and other assets	(5,068)	29,659
Accounts payable and accrued expenses	(5,770)	(2,496)
Deferred revenue	(539)	(157)
Operating lease assets and liabilities	778	37
Other liabilities, net	(3,766)	(1,601)
Net cash used in operating activities	(100,663)	(52,175)
Investing activities:
Purchase of property, plant and equipment	(7,024)	(2,991)
Purchases of marketable securities	(323,975)
Maturities of marketable securities	163,101
Net cash used in investing activities	(167,898)	(2,991)
Financing activities:
Proceeds from issuance of common shares, net of issuance costs	214,592
Proceeds from exercise of options and ESPP contributions, net of issuance costs	11,399	1,132
Net cash provided by financing activities	225,991	1,132
Effect of exchange rate changes on cash	5	(25)
Decrease in cash	(42,565)	(54,059)
Cash, cash equivalents and restricted cash, beginning of period	1,185,468	948,812
Cash, cash equivalents and restricted cash, end of period	1,142,903	894,753
Supplemental disclosure of non-cash investing and financing activities
Property and equipment purchases in accounts payable and accrued expenses	8,847	1,340
Equity issuance costs in accounts payable and accrued expenses	$ 2,868	$ 39