Income Taxes - Unrecognized tax benefits (Details) - USD ($)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Deferred tax assets	$ 11,500,000
Deferred tax assets, valuation allowance	4,694,000	$ 4,356,000
Tax expense (benefits) related to interest and penalties	145,000	12,000
Change in federal tax rate due to the 2017 Act	0	$ 0	$ 11,375,000
Tax benefit from 2017 Act	$ 1,200,000
Statutory federal rate	21.00%	21.00%	35.00%
Amount of interest and penalties	$ 119,000	$ 36,000
Unrecognized tax benefits	1,000,000.0
Reconciliation of the beginning and ending amount of unrecognized tax benefits
Beginning unrecognized tax benefits	624,000	0
Additions for tax positions taken in the prior year	845,000	0
Additions from merger	0	687,000
Reductions for tax positions taken in prior years	(304,000)	(63,000)
Ending unrecognized tax benefits	$ 1,165,000	$ 624,000	$ 0

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Percentage of domestic federal statutory tax rate applicable to pretax income (loss).

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The amount of estimated penalties and interest accrued as of the balance sheet date arising from income tax examinations.

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The sum of the amounts of estimated penalties and interest recognized in the period arising from income tax examinations.

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Amount of income tax expense (benefit) from continuing operations attributable to an adjustment of a deferred tax liability or asset for enacted changes in tax laws or rates or a change in the tax status of the entity.

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Amount 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 increase (decrease) in the valuation allowance for deferred tax assets.

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Amount of income tax expense (benefit) for measurement period adjustment from accounting for tax effect pursuant to Tax Cuts and Jobs Act.

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Amount of unrecognized tax benefits.

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Amount of decrease in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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Amount of increase in unrecognized tax benefits resulting from acquisitions.

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Amount of increase in unrecognized tax benefits resulting from tax positions taken in prior period tax returns.

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The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate.

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