CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Cash flows from operating activities:
Net income	$ 12,876	$ 2,657
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	5,085	2,963
Amortization of marketable securities premium	45	28
Stock-based compensation	3,430	1,932
Provision for doubtful accounts		87
(Gain) loss on disposal of equipment	(8)	36
Return of equity method investments (dividends)	774
Equity in (income) loss of unconsolidated joint ventures	(3,674)	243
Changes in operating assets and liabilities:
Accounts receivable	(11,717)	(3,500)
Inventories	(8,302)	1,638
Prepaid expenses and other current assets	958	(1,790)
Other assets	(525)	(424)
Accounts payable	(1,423)	1,992
Accrued liabilities	(7,192)	(1,226)
Other long-term liabilities, including royalties	(1,064)	1,688
Net cash provided by (used in) operating activities	(10,737)	6,324
Cash flows from investing activities:
Purchases of property, plant and equipment	(19,095)	(12,121)
Purchases of available-for-sale debt securities	(6,691)	(2,880)
Proceeds from sales and maturities of available-for-sale debt securities	240	4,901
Net cash used in investing activities	(25,546)	(10,100)
Cash flows from financing activities:
Proceeds from common stock options exercised	1,592	1,137
Proceeds from short-term loan	5,845	3,380
Proceeds from long-term loan, related party	929
Payments on short-term loan	(3,096)	(5,801)
Proceeds from sale of subsidiary shares to noncontrolling interests	538	396
Formation of new subsidiary with noncontrolling interests	1,283
Costs related to issuance of Tongmei's common stock to redeemable noncontrolling interests, net of proceeds	(12)
Dividends paid by joint ventures to their minority shareholders		(89)
Net cash provided by (used in) financing activities	7,079	(977)
Effect of exchange rate changes on cash and cash equivalents	210	245
Net decrease in cash and cash equivalents	(28,994)	(4,508)
Cash and cash equivalents at the beginning of the year	72,602	26,892
Cash and cash equivalents at the end of the period	$ 43,608	$ 22,384