Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities
Net income (loss)	$ (780)	$ 110
Adjustments to reconcile net income (loss) to net cash used in operating activities
Depreciation and amortization	85	206
Net gain on sale or disposal of assets	(151)	(1,614)
Stock-based compensation	471	297
Changes in operating assets and liabilities:
Accounts receivable	204	211
Inventories	189	242
Other inventory supplies	44	72
Prepaid expenses and other assets	(76)	(560)
Accounts payable	(30)	(413)
Accrued payroll	37	(66)
Accrued real estate taxes	5	(100)
Corporate income and franchise taxes	(7)	(21)
Advanced payments	(22)	(24)
Accrued and other current liabilities	(54)	(15)
Net cash used in operating activities	(85)	(1,675)
Cash flows from investing activities
Purchase of property and equipment	(48)
Proceeds from sale or disposal of assets	151	3,195
Purchases of investments	(1,354)	(7,139)
Proceeds from sale of investments	235	102
Net cash used in investing activities	(1,016)	(3,842)
Cash flows from financing activities
Taxes paid related to net share settlement of equity awards	(2)	(5)
Purchases of common stock	(501)
Net cash used in financing activities	(503)	(5)
Net effect of currency translation		(1)
Net decrease in cash, cash equivalents and restricted cash	(1,604)	(5,523)
Cash, cash equivalents and restricted cash, beginning of period	11,410	11,725
Cash, cash equivalents and restricted cash, end of period	$ 9,806	$ 6,202