Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities:
Net income	$ 42,921	$ 21,677	$ 19,458
Adjustments to reconcile net income from operations to net cash used in operating activities
Depreciation and amortization	2,353	1,055	788
Loss on disposals of property, plant and equipment	0	25	294
Equity income in net income of affiliates	(4,637)	(655)	(168)
Unrealized gain on trading securities	(607)	(12,574)	0
Deferred income taxes	(1,840)	(4,085)	(3,719)
Stock-based compensation	5,117	5,628	3,572
Change in fair value of financial liability	0	11,964	0
Net changes in operating assets and liabilities:
Accounts receivable	(47,624)	(22,085)	(6,961)
Income tax recoverable	(1,082)	0	0
Other receivables	(8,420)	(6,882)	891
Inventory	(127,656)	(40,768)	(6,658)
Prepaid expenses	(10,606)	(3,518)	(83)
Other long-term assets	(4,521)	(99)	(151)
Accounts payable	65,211	21,275	(3,058)
Advances from customers	34,831	8,578	705
Income tax payable	226	(3,137)	1,952
FIN-48 payable	2,200	(83)	0
Other payables and accrued expenses	10,551	5,236	2,865
Deferred revenue	3,180	1,343	0
Other long-term liabilities	310	3,558	(324)
Net cash flow (used in) provided by operating activities	(40,093)	(13,547)	9,403
Cash flows from investing activities:
Purchase of property and equipment	(9,153)	(5,211)	(971)
Purchase of intangible assets	(559)	(324)	(154)
Purchase of land-use-right	0	(9,744)	0
Purchase of trading securities	0	(15,020)	0
Prepayment for property	0	(40,206)	0
Investments in unconsolidated affiliates	(1,568)	0	(4,406)
Dividends from unconsolidated affiliates	0	555	0
Net cash used in investing activities	(11,280)	(69,950)	(5,531)
Cash flows from financing activities:
Proceeds from short-term borrowings	22,884	32,573	18,423
Repayments of short-term borrowings	(39,809)	(20,234)	(14,005)
Proceeds from long-term borrowings	7,056	19,699	0
Repayments of long-term borrowings	(2,127)	(129)	0
Repayments of notes payable	0	(1,820)	0
Proceeds from stock option exercise to common stock	3,430	2,745	317
Proceeds from issuance of Class A common stock in connection with public offering, net of direct issuance expenses of $2,287	0	0	26,434
Payment for repurchase of Class A common stock	0	0	(2,827)
Payment for cancellation of stock option	0	0	(576)
Proceeds from issuance of common stock to redeemable Non-controlling interest	0	0	59,679
Proceeds from a subsidiary equity issuance, net of issuance costs	545,512	0	0
Proceeds from warrant exercise to common stock	1,820	0	0
Net cash provided by financing activities	538,766	32,834	87,445
Effect of exchange rate changes on cash, cash equivalents and restricted cash	3,908	4,570	(582)
Net increase (decrease) in cash and cash equivalents	491,301	(46,093)	90,735
Cash, cash equivalents and restricted cash at beginning of period	71,766	117,859	27,124
Cash, cash equivalents and restricted cash at end of period	563,067	71,766	117,859
Supplemental disclosure of cash flow information:
Interest paid, net of capitalized interest	765	982	745
Cash paid for income taxes	1,132	4,971	1,156
Reconciliation of cash, cash equivalents and restricted cash in condensed consolidated statements of cash flows:
Cash and cash equivalents	563,067	71,766	58,261
Restricted cash	0	0	59,598
Non-cash financing activities:
Warrant conversion to common stock	0	399	9
Share cancellation, (note 16)	0	9,715	0
Cashless exercise of stock options	137	0	0
Issuance of warrant for settlement of financial liability and cancellation of note receivable	$ 0	$ 19,859	$ 0