Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities
Net loss	$ (334,620)	$ (443,286)	$ (704,471)
Adjustments to reconcile net loss to net cash used in operating activities:
Allowance for credit loss	6	1	10
Inventory write-down	973	477	1,368
Depreciation and amortization expenses	9,029	8,227	6,487
Impairment of property and equipment	57	0	0
Amortization of deferred income	(3,383)	(2,602)	(521)
Share-based compensation	79,634	61,302	40,714
Noncash research and development expenses	0	0	62,250
Share of loss from equity method investment	0	221	1,057
(Gain) loss from fair value changes of equity investment with readily determinable fair value	(2,789)	8,952	14,617
Loss on disposal of property and equipment	159	560	29
Gain on disposal of land use right	(408)	0	0
Noncash lease expenses	8,708	8,350	6,119
Gain from sale of intellectual property	(10,000)	0	0
Foreign currency remeasurement loss (gain)	14,850	56,403	(10,679)
Changes in operating assets and liabilities:
Accounts receivable	(20,040)	4,330	(42,319)
Notes receivable	2,352	(1,976)	(7,335)
Inventories	(14,907)	(15,382)	(7,174)
Prepayments and other current assets	12,246	(19,258)	(7,086)
Long-term deposits	187	(527)	(8)
Value added tax recoverable	0	22,781	(1,717)
Accounts payable	36,803	(53,773)	63,522
Other current liabilities	19,810	7,392	30,142
Operating lease liabilities	(8,351)	(8,455)	(5,385)
Deferred income	11,181	(1,379)	11,149
Other non-current Liabilities	325	0	0
Net cash provided by (used in) operating activities	(198,178)	(367,642)	(549,231)
Cash flows from investing activities
Purchase of short-term investments	(134,000)	(260,274)	(445,000)
Proceeds from maturity of short-term investments	117,700	705,274	743,902
Purchase of investment in equity investee	0	0	(30,000)
Purchase of property and equipment	(7,212)	(24,585)	(18,295)
Proceeds from the sale of property and equipment	122	0	3
Acquisition of intangible assets	(1,279)	(399)	(653)
Proceeds from sale of intellectual property	10,000	0	0
Proceeds from disposal of land use right	3,893	0	0
Net cash (used in) provided by investing activities	(10,776)	420,016	249,957
Cash flows from financing activities
Proceeds from exercises of stock options	2,369	5,870	7,417
Proceeds from issuance of ordinary shares upon public offerings	0	0	818,875
Payment of public offering costs	0	0	(1,837)
Taxes paid related to settlement of equity awards	(8,802)	(7,600)	(4,253)
Net cash (used in) provided by financing activities	(6,433)	(1,730)	820,202
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	(2,622)	(6,274)	1,116
Net (decrease) increase in cash, cash equivalents and restricted cash	(218,009)	44,370	522,044
Cash, cash equivalents and restricted cash — beginning of the year	1,009,273	964,903	442,859
Cash, cash equivalents and restricted cash — end of the year	791,264	1,009,273	964,903
Supplemental disclosure on non-cash investing and financing activities
Payables for purchase of property and equipment	2,474	5,269	2,568
Payables for acquisition of intangible assets	11,516	163	191
Payables for treasury stock	0	2	26
Right-of-use asset acquired under operating leases	3,668	14,801	2,183
Receivables for disposal of property and equipment	0	64	0
Supplemental disclosure of cash flow information
Cash and cash equivalents	790,151	1,008,470	964,100
Restricted cash, non-current	1,113	803	803
Total cash and cash equivalents and restricted cash	$ 791,264	$ 1,009,273	$ 964,903