Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Operating activities
Net loss	$ (2,586)	$ (4,093)	$ (10,763)	$ (8,974)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization			4	4
Amortization of operating lease asset			88	86
Warrant inducement expense			4,829
Stock-based compensation	197	627	634	838
Changes in operating assets and liabilities:
Prepaid expenses and other assets			311	(60)
Accounts payable and accrued expenses			(233)	(759)
Operating lease liability			(88)	(80)
Net cash used in operating activities			(5,218)	(8,945)
Financing activities
Proceeds from issuances of common stock, net				9,676
Proceeds from exercise of warrants, net			5,191
Net cash provided by financing activities			5,191	9,676
Net change in cash			(27)	731
Cash at beginning of period	$ 8,764	$ 13,703	$ 8,791	$ 12,972	$ 12,972
Cash at end of period					$ 8,791