CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Cash flows from operating activities:
Net income	$ 1,176	$ 715
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	1,968	2,830
Amortization of marketable securities premium	20	23
Impairment charge on equity investee		1,068
Stock-based compensation	1,284	1,126
Provision for doubtful accounts	43
Loss on disposal of equipment		30
Gain from deconsolidation of a subsidiary		(175)
Loss from equity method investments, net	288	553
Return on equity method investments		362
Changes in operating assets and liabilities:
Accounts receivable	(854)	1,304
Inventories	(902)	8,209
Prepaid expenses and other current assets	(996)	4,870
Other assets	(1,402)	(3,173)
Accounts payable	1,538	(7,330)
Accrued liabilities	(1,352)	(4,664)
Other long-term liabilities, including royalties	1,172	199
Net cash provided by operating activities	1,983	5,947
Cash flows from investing activities:
Purchases of property, plant and equipment	(6,465)	(8,226)
Purchases of available-for-sale securities		(2,514)
Proceeds from sales and maturities of available-for-sale debt securities	3,461	16,640
Net cash provided by (used in) investing activities	(3,004)	5,900
Cash flows from financing activities:
Proceeds from common stock options exercised	513	232
Proceeds from sale of previously consolidated subsidiary shares		366
Consideration paid to repurchase subsidiary shares from noncontrolling interests		(262)
Proceeds from short-term loan	395
Dividends paid by joint ventures to their minority shareholders	(89)
Net cash provided by financing activities	819	336
Effect of exchange rate changes on cash and cash equivalents	(175)	23
Net increase (decrease) in cash and cash equivalents	(377)	12,206
Cash and cash equivalents at the beginning of the year	26,892	16,526
Cash and cash equivalents at the end of the year	$ 26,515	28,732
Supplemental disclosure of non-cash flow information:
Consideration payable to repurchase subsidiary shares from noncontrolling interests, included in accrued liabilities		151
Reduction of noncontrolling interests in excess (deficit) of total consideration paid and payable in connection with the repurchase of subsidiary shares from noncontrolling interests		$ (74)