Consolidated statements of cash flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Operating activities
Net loss	$ (492,646)	$ (192,358)
Adjustments to reconcile net loss to net cash used in operating activities:
Allowance for doubtful accounts	5	2
Inventory write-down	402
Depreciation and amortization expenses	4,612	3,253
Amortization of deferred income	(234)	(234)
Share-based compensation	28,106	20,405
Noncash research and development expenses	62,250
Share of loss from equity method investment	548	671
Loss from fair value changes of equity investment with readily determinable fair value	9,930	0
Loss on disposal of property and equipment	12	1
Noncash lease expenses	4,595	3,251
Changes in operating assets and liabilities:
Accounts receivable	(15,858)	(3,704)
Inventories	248	(3,631)
Prepayments and other current assets	(6,142)	(3,564)
Long term deposits	(39)	(474)
Value added tax recoverable	(1,249)	(6,845)
Accounts payable	(11,235)	5,217
Other current liabilities	23,429	(4,981)
Operating lease liabilities	(3,834)	(2,335)
Deferred income	863	13,606
Net cash used in operating activities	(396,237)	(171,720)
Cash flows from investing activities:
Purchases of short-term investments	(170,000)	(749,676)
Proceeds from maturity of short-term investment	743,902
Purchase of property and equipment	(11,920)	(4,835)
Purchase of intangible assets	(539)	(370)
Payment for investment in equity investee	(30,000)
Disposal of property and equipment	3
Net cash provided by (used in) investing activities	531,446	(754,881)
Cash flows from financing activities:
Repayment of short-term borrowings		(4,292)
Proceeds from exercises of stock options	6,907	4,083
Proceeds from issuance of ordinary shares upon public offerings	818,874	1,025,970
Payment of public offering costs	(1,836)	(1,275)
Employee taxes paid related to net share settlement of equity awards	(3,467)
Net cash provided by financing activities	820,478	1,024,486
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	695	2,062
Net increase in cash, cash equivalents and restricted cash	956,382	99,947
Cash, cash equivalents and restricted cash - beginning of period	442,859	76,442
Cash, cash equivalents and restricted cash - end of period	1,399,241	176,389
Supplemental disclosure on non-cash investing and financing activities:
Payables for purchase of property and equipment	1,797	2,334
Payables for intangible assets	24	21
Payables for public offering costs		4,909
Supplemental disclosure of cash flow information:
Cash and cash equivalents	1,398,498	175,879
Restricted cash, non-current	743	510
Total cash and cash equivalents and restricted cash	$ 1,399,241	176,389
Interest paid		$ 157