Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net loss			$ (6,945)	$ (6,569)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	$ 226	$ 270	770	814
Accretion of asset retirement obligation			184	167
Decrease in derivative at fair value, net			3
Loss on trading securities				217
Asset write off			100	19
Gain on sale of assets			(25)	(144)
Stock compensation			771	725
Changes in operating assets and liabilities from continuing operations:
(Increase) decrease in lease receivable			(54)	21
Decrease in prepaid expenses and other assets			30	244
Decrease in inventories			33	3
Decrease in value added tax recoverable, net				2
Decrease (increase) in other long term assets			143	(396)
Decrease in reclamation liability			(3)	(68)
(Decrease) increase in accounts payable and accrued liabilities			(823)	135
(Decrease) increase in other current liabilities			(1,594)	1,500
Decrease in deferred revenue			(372)	(219)
(Decrease) increase in other long term liabilities			(109)	427
Net cash used in operating activities			$ (7,891)	$ (3,122)

The increase (decrease) during the reporting period in the aggregate value of plant lease receivables.

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