CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income	$ 18,742	$ 16,509	$ 5,041
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	8,119	7,078	4,333
Amortization of marketable securities premium	58	68	34
Stock-based compensation	4,006	4,519	2,623
Provision for doubtful accounts	(177)	87	183
(Gain) loss on disposal of equipment	(85)	(8)	50
Return of equity method investments (dividends)	1,608	774
Equity in income of unconsolidated joint ventures	(5,957)	(4,409)	(111)
Deferred tax assets	104	2,340
Changes in operating assets and liabilities:
Accounts receivable	4,535	(9,748)	(5,333)
Inventories	(31,412)	(12,401)	(916)
Prepaid expenses and other current assets	(3,486)	(798)	(6,719)
Other assets	(471)	(6,283)	(104)
Accounts payable	(5,519)	3,563	2,305
Accrued liabilities	(2,127)	(3,445)	2,601
Other long-term liabilities, including royalties	3,297	(1,151)	1,878
Net cash provided by (used in) operating activities	(8,765)	(3,305)	5,865
Cash flows from investing activities:
Purchases of property, plant and equipment	(28,465)	(29,645)	(19,855)
Purchases of available-for-sale debt securities	(2,158)	(9,645)	(5,968)
Proceeds from sales and maturities of available-for-sale debt securities	5,400	480	9,401
Net cash used in investing activities	(25,223)	(38,810)	(16,422)
Cash flows from financing activities:
Proceeds from common stock options exercised	518	1,670	2,536
Proceeds from sale of subsidiary shares to noncontrolling interests		538	396
Proceeds from bank loans	53,078	20,543	10,401
Proceeds from long-term loan from noncontrolling interest		1,834
Payments on bank loans	(17,798)	(19,066)	(5,996)
Proceeds from capital increase in subsidiary shares from noncontrolling interest	2,233
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)	47,563
Dividends paid by joint ventures to their minority shareholders			(2,238)
Net cash provided by financing activities	38,031	5,725	52,662
Effect of exchange rate changes on cash and cash equivalents, and restricted cash	542	551	3,605
Net increase (decrease) in cash and cash equivalents, and restricted cash	4,585	(35,839)	45,710
Cash and cash equivalents at the beginning of the year	36,763	72,602	26,892
Cash and cash equivalents, and restricted cash at the end of the period	41,348	36,763	72,602
Supplemental disclosures:
Income taxes paid, net of refunds	1,692	3,177	1,959
Supplemental disclosure of non-cash flow information:
Notes Receivables paid to purchase fixed assets	6,835
Conversion of related party borrowings to Additional Paid-in Capital	1,887
Investment in subsidiary shares from noncontrolling interest	937
Consideration payable to repurchase subsidiary shares from noncontrolling interests, included in accrued liabilities			1,439
Reduction of noncontrolling interests in excess (deficit) of total consideration paid and payable in connection with the repurchase of subsidiary shares from noncontrolling interests			(1,398)
Bank loan proceeds paid directly to a third-party vendor, included in accounts payable	474
Other receivable regarding sales of land and building to unconsolidated joint venture	976
Consideration payable in connection with construction in progress, included in accrued liabilities	$ 4,135	$ 2,974	$ 1,457