Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income	$ 484	$ 5,372
Items not involving cash:
Depreciation, depletion and amortization	3,471	1,234
Accretion of asset retirement obligations	303	155
Unrealized commodity derivative loss (gain)	5,587	(3,023)
Warrant derivative gain	(225)	(1,683)
Stock-based compensation expense	483	539
Equity investment income	(962)
Gain (loss) on derecognized equity investment in affiliate-Carbon California	(5,390)
Amortization of debt issuance costs	247
Other		(72)
Net change in:
Accounts receivable	(353)	1,331
Prepaid expenses, deposits and other current assets	570	(375)
Accounts payable, accrued liabilities, firm transportation contract obligations, and other long-term obligations	(2,600)	(1,142)
Net cash provided by operating activities	1,615	2,336
Cash flows from investing activities:
Development and acquisition of properties and equipment	(40,472)	(1,182)
Cash received- Carbon California Acquisition	275
Other long-term assets		(15)
Investment in affiliates		(240)
Net cash used in investing activities	(40,197)	(1,437)
Cash flows from financing activities:
Proceeds from credit facility	31,502	600
Proceeds from preferred shares	5,000
Payments on credit facility	(14)	(1,300)
Payments of debt issuance costs	(511)
Contributions from non-controlling interests	5,000
Distributions to non-controlling interests	(15)	(43)
Net cash provided by (used in) financing activities	40,962	(743)
Net increase in cash and cash equivalents	2,380	156
Cash and cash equivalents, beginning of period	1,650	858
Cash and cash equivalents, end of period	$ 4,030	$ 1,014