Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Cash flows from operating activities
Net loss - before noncontrolling interest ("NCI")	$ (35,888)	$ (17,268)
Adjustments to reconcile net loss - before NCI to net cash used in operating activities
Depreciation expense	23	14
Stock-based compensation	2,044	1,571
Change in fair value - Senior Secured Convertible Notes and Senior Convertible Note	5,327	559
Debt extinguishment loss - Senior Secured Convertible Notes	6,497	1,831
Changes in operating assets and liabilities:
Prepaid expenses and other current assets	(1,336)	(90)
Accounts payable	501	613
Accrued expenses and other current liabilities	918	56
Deposits - Long-Term		(643)
Net cash flows used in operating activities	(21,914)	(13,357)
Cash flows from investing activities
Purchase of equipment	(55)	(27)
Net cash flows used in investing activities	(55)	(27)
Cash flows from financing activities
Proceeds - issue of Senior Secured Convertible Notes	13,300
Proceeds - issue of Senior Convertible Note	3,700	6,300
Proceeds - Cares Act Paycheck Protection Program Loan	300
Proceeds - issue of common stock - registered offerings	16,032	5,413
Payment - offering costs - registered offerings	(100)	(34)
Payment - Senior Secured Convertible Note		(86)
Payment - Senior Secured Convertible Notes - non-installment payments	(600)	(279)
Proceeds - issue common stock - Employee Stock Purchase Plan	357	67
Proceeds - exercise of Series S Warrants	12
Proceeds - exercise of stock options issued under equity incentive plan of majority owned subsidiary	5
Net cash flows provided by financing activities	33,006	11,381
Net increase (decrease) in cash	11,037	(2,003)
Cash, beginning of period	6,219	8,222
Cash, end of period	$ 17,256	$ 6,219