Schedule I — Condensed Financial Information of Registrant - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Cash flows from Operating activities:
Net loss	$ (257,103)	$ (334,620)	$ (443,286)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of deferred income	(3,520)	(3,383)	(2,602)
Share-based compensation	70,651	79,634	61,302
Loss from fair value changes of equity investment of readily determinable fair value	6,105	(2,789)	8,952
Changes in operating assets and liabilities:
Prepayments and other current assets	(18,729)	12,246	(19,258)
Other current liabilities	(22,022)	19,810	7,392
Net cash used in operating activities	(214,869)	(198,178)	(367,642)
Cash flows from investing activities
Purchases of short-term investments	(330,000)	(134,000)	(260,274)
Proceeds from maturity of short-term investments	16,300	117,700	705,274
Net cash (used in) provided by investing activities	(375,193)	(10,776)	420,016
Cash flows from financing activities
Proceeds from exercises of stock options	3,200	2,369	5,870
Proceeds from issuance of ordinary shares upon public offerings	217,350	0	0
Payment of public offering costs	(1,283)	0	0
Employee taxes paid related to settlement of equity awards	0	(8,802)	(7,600)
Net cash provided by (used in) financing activities	349,889	(6,433)	(1,730)
Effect of foreign exchange rate changes on cash and cash equivalent	(310)	(2,622)	(6,274)
Net (decrease) increase in cash, cash equivalents and restricted cash	(240,483)	(218,009)	44,370
Cash, cash equivalents and restricted cash — beginning of the year	791,264	1,009,273	964,903
Cash, cash equivalents and restricted cash — end of the year	550,781	791,264	1,009,273
Parent Company
Cash flows from Operating activities:
Net loss	(257,103)	(334,620)	(443,286)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Amortization of deferred income	0	0	(234)
Share-based compensation	4,759	3,217	3,724
Equity in loss of subsidiaries	259,558	352,449	427,514
Loss from fair value changes of equity investment of readily determinable fair value	6,105	(2,789)	8,952
Changes in operating assets and liabilities:
Prepayments and other current assets	2,266	2,780	(7,839)
Other current liabilities	(248)	(379)	1,648
Net cash used in operating activities	15,337	20,658	(9,521)
Cash flows from investing activities
Purchases of short-term investments	(330,000)	0	(260,274)
Proceeds from maturity of short-term investments	0	0	705,274
Investment in subsidiaries	(271,830)	(392,893)	(80,942)
Net cash (used in) provided by investing activities	(601,830)	(392,893)	364,058
Cash flows from financing activities
Proceeds from exercises of stock options	3,200	2,369	5,870
Proceeds from issuance of ordinary shares upon public offerings	217,350	0	0
Payment of public offering costs	(1,283)	0	0
Employee taxes paid related to settlement of equity awards	0	(8,802)	(7,600)
Net cash provided by (used in) financing activities	219,267	(6,433)	(1,730)
Effect of foreign exchange rate changes on cash and cash equivalent	0	0	0
Net (decrease) increase in cash, cash equivalents and restricted cash	(367,226)	(378,668)	352,807
Cash, cash equivalents and restricted cash — beginning of the year	565,981	944,649	591,842
Cash, cash equivalents and restricted cash — end of the year	$ 198,755	$ 565,981	$ 944,649