Unaudited Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities
Net loss	$ (170,039)	$ (220,327)
Adjustments to reconcile net loss to net cash used in operating activities:
Allowance for credit loss (gain)	3	(3)
Inventory write-down	623	193
Depreciation and amortization expenses	4,652	3,874
Amortization of deferred income	(1,716)	(1,386)
Share-based compensation	37,172	26,634
Share of loss from equity method investment	0	221
Loss from fair value changes of equity investment with readily determinable fair value	1,304	12,556
Loss (gain) on disposal of property and equipment	260	(11)
Gain on disposal of land use right	(404)	0
Noncash lease expenses	4,383	3,825
Gain from sale of intellectual property	(10,000)	0
Foreign currency remeasurement loss	31,167	32,610
Changes in operating assets and liabilities:
Accounts receivable	(8,863)	20,422
Notes receivable	(12,714)	(3,633)
Inventories	(6,627)	(4,582)
Prepayments and other current assets	87	48
Long-term deposits	(184)	(78)
Value added tax recoverable	0	23,602
Accounts payable	3,037	(17,718)
Other current liabilities	(6,761)	(3,100)
Operating lease liabilities	(3,596)	(3,849)
Deferred income	9,902	(1,325)
Other non-current liabilities	325	0
Net cash used in operating activities	(127,989)	(132,027)
Cash flows from investing activities
Purchases of short-term investments	(100,000)	(260,274)
Proceeds from maturity of short-term investment	84,500	130,000
Purchase of property and equipment	(5,234)	(13,488)
Proceeds from the sale of property and equipment	112	0
Purchase of intangible assets	(630)	(107)
Proceeds from sale of intellectual property	10,000	0
Net cash used in investing activities	(11,252)	(143,869)
Cash flows from financing activities
Proceeds from exercises of stock options	1,762	4,619
Taxes paid related to settlement of equity awards	(7,141)	(6,859)
Net cash used in financing activities	(5,379)	(2,240)
Effect of foreign exchange rate changes on cash, cash equivalents and restricted cash	(3,707)	(5,144)
Net decrease in cash, cash equivalents and restricted cash	(148,327)	(283,280)
Cash, cash equivalents and restricted cash - beginning of period	1,009,273	964,903
Cash, cash equivalents and restricted cash - end of period	860,946	681,623
Supplemental disclosure on non-cash investing and financing activities
Payables for purchase of property and equipment	4,344	1,661
Payables for intangible assets	96	270
Payables for treasury stock	1,531	17
Receivables for stock option exercise under equity incentive plans	0	12
Right-of-use asset acquired under operating leases	3,313	8,451
Receivables for disposal of land use right	3,867	0
Supplemental disclosure of cash flow information
Cash and cash equivalents	859,155	680,820
Restricted cash, non-current	1,791	803
Total cash and cash equivalents and restricted cash	$ 860,946	$ 681,623