Condensed Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Deficit	Total
Beginning balance (in shares) at Dec. 31, 2017	3,081,546
Beginning balance at Dec. 31, 2017	$ 3	$ 64	$ (1,332)	$ (1,265)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	0	34	0	34
Reclass of Series B warrants from warrant liability to stockholders' equity				0
Issuance of common stock for conversion of debt and accrued interest				0
Net loss	$ 0	0	(2,255)	(2,255)
Ending balance (in shares) at Sep. 30, 2018	3,081,546
Ending balance at Sep. 30, 2018	$ 3	98	(3,587)	(3,486)
Beginning balance (in shares) at Jun. 30, 2018	3,081,546
Beginning balance at Jun. 30, 2018	$ 3	95	(2,490)	(2,392)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	0	3	0	3
Net loss	$ 0	0	(1,097)	(1,097)
Ending balance (in shares) at Sep. 30, 2018	3,081,546
Ending balance at Sep. 30, 2018	$ 3	98	(3,587)	(3,486)
Beginning balance (in shares) at Dec. 31, 2018	3,081,546
Beginning balance at Dec. 31, 2018	$ 3	97	(4,806)	(4,706)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	315	0	315
Issuance of common stock and warrants in a private offering, net of $16.5 million warrant liability, shares	1,829,407
Issuance of common stock and warrants in a private offering, net of $16.5 million warrant liability	$ 2	0	0	2
Effect of reverse merger, shares	947,218
Effect of reverse merger	$ 1	(300)	0	(299)
Issuance of common stock in at-the-market offering, net of issuance, shares	1,197,676
Issuance of common stock in at-the-market offering, net of issuance	$ 1	2,566	0	2,567
Issuance of common stock and warrants, pursuant to Securities Purchase Agreement, net of issuance, shares	4,475,000
Issuance of common stock and warrants, pursuant to Securities Purchase Agreement, net of issuance	$ 5	5,925	0	5,930
Warrants exercised for cash, shares	14,253,992
Warrants exercised for cash	$ 14	4,429	0	4,443
Issuance of common stock for license acquired, shares	992,782
Issuance of common stock for license acquired	$ 1	2,999	0	3,000
Reclass of warrant liabilites related to Series A warrants exercised for cash, shares	0
Reclass of warrant liabilites related to Series A warrants exercised for cash	$ 0	5,504	0	5,504
Reclass of Series B warrants from warrant liability to stockholders' equity, shares	0
Reclass of Series B warrants from warrant liability to stockholders' equity	$ 0	31,473	0	31,473
Issuance of common stock for conversion of debt and accrued interest, shares	172,284
Issuance of common stock for conversion of debt and accrued interest	$ 0	2,715	0	2,715
Net loss	$ 0	0	(37,375)	(40,596)
Ending balance (in shares) at Sep. 30, 2019	26,949,905
Ending balance at Sep. 30, 2019	$ 27	55,723	(45,402)	10,348
Beginning balance (in shares) at Jun. 30, 2019	21,277,229
Beginning balance at Jun. 30, 2019	$ 21	47,099	(42,181)	4,939
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock-based compensation expense	$ 0	133	0	133
Issuance of common stock in at-the-market offering, net of issuance, shares	1,197,676
Issuance of common stock in at-the-market offering, net of issuance	$ 1	2,566	0	2,567
Issuance of common stock and warrants, pursuant to Securities Purchase Agreement, net of issuance, shares	4,475,000
Issuance of common stock and warrants, pursuant to Securities Purchase Agreement, net of issuance	$ 5	5,925	0	5,930
Net loss	$ 0	0	(3,221)	(3,221)
Ending balance (in shares) at Sep. 30, 2019	26,949,905
Ending balance at Sep. 30, 2019	$ 27	$ 55,723	$ (45,402)	$ 10,348