Income Taxes - Significant Components of Company's Taxes (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax computed at the federal statutory rate	$ (3,447)	$ (3,457)
State tax, net of federal tax benefit	(177)	(184)
Permanent Items	353	481
Stock options true-up	875	0
Tax credits	(384)	(574)
Valuation allowance increase (decrease)	2,780	3,734
Provision for income taxes	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax computed at the federal statutory rate	21.00%	21.00%
State tax, net of federal tax benefit	1.00%	1.00%
Permanent Items	(2.00%)	(3.00%)
Stock options true-up	(5.00%)	0.00%
Tax credits	2.00%	3.00%
Valuation allowance increase (decrease)	(17.00%)	(22.00%)
Provision for income taxes	0.00%	0.00%

Represents the percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to permanent items.

No definition available.