Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities
Net loss	$ (443,286)	$ (704,471)	$ (268,905)
Adjustments to reconcile net loss to net cash used in operating activities:
Allowance for credit loss	1	10	1
Inventory write-down	477	1,368	29
Depreciation and amortization expenses	8,227	6,487	4,640
Amortization of deferred income	(2,602)	(521)	(312)
Share-based compensation	61,302	40,714	24,830
Non-cash research and development expenses	0	62,250	0
Share of loss from equity method investment	221	1,057	1,119
Loss from fair value changes of equity investment with readily determinable fair value	8,952	14,617	0
Loss (gain) on disposal of property and equipment	560	29	(21)
Non-cash lease expenses	8,350	6,119	4,318
Foreign currency remeasurement loss (gain)	56,403	(10,679)	(21,659)
Changes in operating assets and liabilities:
Accounts receivable	4,330	(42,319)	(1,375)
Notes receivable	(1,976)	(7,335)	0
Inventories	(15,382)	(7,174)	(7,168)
Prepayments and other current assets	(19,258)	(7,086)	(4,199)
Long-term deposits	(527)	(8)	(485)
Value added tax recoverable	22,781	(1,717)	(8,404)
Accounts payable	(53,773)	63,522	39,981
Other current liabilities	7,392	30,142	10,682
Operating lease liabilities	(8,455)	(5,385)	(3,416)
Deferred income	(1,379)	11,149	14,289
Net cash used in operating activities	(367,642)	(549,231)	(216,055)
Cash flows from investing activities
Purchases of short-term investments	(260,274)	(445,000)	(949,161)
Proceeds from maturity of short-term investments	705,274	743,902	405,000
Purchases of investment in equity investee	0	(30,000)	0
Purchases of property and equipment	(24,585)	(18,295)	(10,130)
Proceeds from disposal of property and equipment	0	3	0
Purchases of intangible assets	(399)	(653)	(539)
Net cash provided by (used in) investing activities	420,016	249,957	(554,830)
Cash flows from financing activities
Repayment of short-term borrowings	0	0	(6,527)
Proceeds from exercises of stock options	5,870	7,417	6,664
Proceeds from issuance of ordinary shares upon public offerings	0	818,875	1,137,683
Payment of public offering costs	0	(1,837)	(5,380)
Employee taxes paid related to settlement of equity awards	(7,600)	(4,253)	0
Net cash (used in) provided by financing activities	(1,730)	820,202	1,132,440
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	(6,274)	1,116	4,862
Net increase in cash, cash equivalents and restricted cash	44,370	522,044	366,417
Cash, cash equivalents and restricted cash — beginning of the year	964,903	442,859	76,442
Cash, cash equivalents and restricted cash — end of the year	1,009,273	964,903	442,859
Supplemental disclosure on non-cash investing and financing activities
Payables for purchase of property and equipment	5,269	2,568	788
Payables for purchase of intangible assets	163	191	70
Payables for public offering costs	0	0	1,063
Payables for treasury stock	2	26	0
Right-of-use asset acquired under operating leases	14,801	2,183	6,393
Receivables for disposal of property and equipment	64	0	0
Supplemental disclosure of cash flow information
Cash and cash equivalents	1,008,470	964,100	442,116
Restricted cash, non-current	803	803	743
Total cash and cash equivalents and restricted cash	1,009,273	964,903	442,859
Interest paid	$ 0	$ 0	$ 189