Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (29,528)	$ (26,273)
Adjustments to reconcile net loss to net cash used for operating activities:
Depreciation	265	258
Unrealized gain on warrant derivative liabilities		(1,522)
Amortization of deferred loan costs	81	103
Amortization of debt discount	3,856	3,920
Interest expense added to loan principal	10,031	9,767
Interest expense added to lease liability	1,272	1,111
Loss on equity method investments	490
Loss on debt conversions	38	175
Debt conversion expense	197
Compensation charge for stock awards and share options	562	473
Changes in operating assets and liabilities:
Accounts receivable	(11)	(2)
Prepaid expenses and other current assets	22	3
Other assets	(186)	73
Accounts payable	(68)	(98)
Accrued and other liabilities	(729)	(181)
Net cash used for operating activities	(13,708)	(12,193)
Cash flows from investing activities:
Additions to long-term deposit		(2,000)
Contributions and advances to equity-method investments	(904)
Additions to property, plant and equipment	(1,599)	(1,726)
Net cash used for investing activities	(2,503)	(3,726)
Cash flows from financing activities:
Net proceeds from issuance of common stock	19,395	15,503
Principal payments on long-term debt	(59)	(56)
Net cash provided by financing activities	19,336	15,447
Net increase (decrease) in cash and cash equivalents and restricted cash	3,125	(472)
Cash and cash equivalents and restricted cash, beginning of period	12,691	13,163
Cash and cash equivalents and restricted cash, end of period	$ 15,816	$ 12,691