Income Taxes - Reconciliation Between Income Taxes at Statutory Tax Rate (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Loss before income taxes	$ (8,599)	$ (8,583)
Tax (benefit) at statutory tax rate	(1,806)	(1,802)
Effects of:
Exclusion of incentive stock option expense	53	47
R&D tax credits	(290)	(238)
Increase (decrease) in valuation allowance	2,041	1,845
FMV of warrants	0	0
Prior year adjustments	0	0
Carryforward adjustment	2	2
ASC 718 additional paid in capital adjustment	0	146
Rate change on net deferred tax asset	0	0
Provision for income taxes	0	0
Unrecognized tax benefits	0
Unrecognized tax benefits, interest and penalties recorded	0
Unrecognized tax benefits, interest and penalties accrued	$ 0	$ 0