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 income (loss)	$ (19,193)	$ 18,742	$ 16,509
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation and amortization	8,722	8,119	7,078
Amortization of marketable securities premium	18	58	68
Stock-based compensation	3,540	4,006	4,519
Provision for credit losses	272	(177)	87
Loss on sale of equity investment	166
(Gain) Loss on disposal of equipment	21	(85)	(8)
Return of equity method investments (dividends)	4,316	1,608	774
Equity in income of unconsolidated joint ventures	(2,050)	(5,957)	(4,409)
Deferred tax assets	553	104	2,340
Changes in operating assets and liabilities:
Accounts receivable	9,306	4,535	(9,748)
Inventories	1,073	(31,412)	(12,401)
Prepaid expenses and other current assets	(652)	(3,486)	(798)
Other assets	419	(471)	(6,283)
Accounts payable	(162)	(5,519)	3,563
Accrued liabilities	(1,897)	(2,127)	(3,445)
Other long-term liabilities	(1,049)	3,297	(1,151)
Net cash provided by (used in) operating activities	3,403	(8,765)	(3,305)
Cash flows from investing activities:
Purchases of property, plant and equipment	(10,475)	(28,465)	(29,645)
Purchases of available-for-sale debt securities		(2,158)	(9,645)
Proceeds from sales and maturities of available-for-sale debt securities	9,582	5,400	480
Proceeds from sales of equity securities - 15% of Jia Mei	827
Investments in non-marketable equity investments	(2,538)
Net cash used in investing activities	(2,604)	(25,223)	(38,810)
Cash flows from financing activities:
Proceeds from common stock options exercised	10	518	1,670
Proceeds from sale of subsidiary shares to noncontrolling interests			538
Proceeds from short-term bank loans	56,470	53,078	20,543
Proceeds from long-term loan from noncontrolling interest			1,834
Payments on short-term bank loans	(49,210)	(17,798)	(19,066)
Proceeds from capital increase in subsidiary shares from noncontrolling interests	708	2,233
Proceeds from long-term loan	635
Formation of new subsidiary with noncontrolling interests			1,283
Proceeds from issuance of Tongmei's common stock to redeemable noncontrolling interests, net of costs			(1,077)
Net cash provided by financing activities	8,613	38,031	5,725
Effect of exchange rate changes on cash and cash equivalents, and restricted cash	(646)	542	551
Net increase (decrease) in cash and cash equivalents, and restricted cash	8,766	4,585	(35,839)
Cash, restricted cash and cash equivalents at the beginning of the year	41,348	36,763	72,602
Cash, restricted cash and cash equivalents at the end of the period	50,114	41,348	36,763
Supplemental disclosures:
Income taxes paid, net of refunds	686	1,692	3,177
Interest expense paid	1,564
Supplemental disclosure of non-cash flow information:
Loan proceeds received by notes receivable	1,481
Notes receivables paid to purchase fixed assets	4,170	6,835
Non-cash consideration received from sale of DongFang	585
Conversion of related party borrowings to Additional Paid-in Capital		1,887
Investment in subsidiary shares from noncontrolling interest	308	937
Bank loan proceeds paid directly to a third-party vendor, included in accounts payable		474
Sales of land and building to unconsolidated joint venture		976
Consideration payable in connection with construction in progress, included in accrued liabilities	$ 6,574	$ 4,135	$ 2,974