Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Operating activities:
Net loss	$ (12,004)	$ (21,987)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	19	48
Noncash interest expense	819	3,037
Stock based compensation expense	4,812	2,115
Change in fair value of warrants issued in connection with acquisition of licenses		(97)
Issuance of common stock in lieu of cash compensation	85
Issuance of common stock in exchange for services	81	12
Gain on disposal of assets	(276)
Changes in operating assets and liabilities:
Prepaid expenses and other assets	328	831
Accounts payable	(198)	(520)
Accrued expenses	125	2,571
Liabilities subject to compromise		(259)
Net cash used in operating activities	(6,209)	(14,249)
Financing activities:
Net proceeds from issuance of common stock	2,781
Net proceeds from Term loan	50	12,080
Net proceeds from issuance of Convertible notes	2,500
Net proceeds from issuance of Advance notes	925
Net cash provided by financing activities	6,256	12,080
Net increase (decrease) in cash, cash equivalents and restricted cash	47	(2,169)
Cash, cash equivalents and restricted cash, beginning of period	737	3,007
Cash, cash equivalents and restricted cash, end of period	814	737
Supplemental cash flow disclosure:
Cash paid for interest	8	6
Supplemental disclosure of non-cash investing and financing activities:
Conversion of notes payable and related accrued interest and fees to common stock	18,432
Change in fair value of warrants issued in connection with acquisition of licenses		(97)
Beneficial conversion feature of Advance notes	271
Beneficial conversion feature of Convertible notes	1,465
Issuance in stock options for payment of accrued compensation	303
Issuance of common stock in exchange for services	81	12
Issuance of common stock in lieu of cash compensation	$ 85