Income Taxes (Income Tax Provision (Benefit) Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Tax provision (benefit) at statutory U.S. federal income tax rate	$ 14,893	$ 3,455	$ (17,194)
State income tax — net of federal income tax benefit	3,049	937	(1,746)
Impact of Tax Cuts and Job Act			(15,720)
Change in state law regarding NOL carryforwards		658
Change in deferred state tax rate	(1,835)
Stock based compensation	(1,266)	(8)
Nondeductible officer compensation	1,021	201
Research and development tax credits	(452)	(218)	(170)
Changes in unrecognized tax benefits	(56)	14	10
Changes in valuation allowance	(3)	116	1,152
Other	(98)	282	(93)
Income tax provision (benefit)	$ 15,253	$ 5,437	$ (33,761)

Income tax expense (benefit) excluding discontinued operations.

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Income tax reconciliation change in deferred state tax rate

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Income tax reconciliation change in state law regarding non operating loss carryforwards.

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Income tax reconciliation, changes in unrecognized tax benefits

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Income tax reconciliation nondeductible expense officer compensation.

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Amount of difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying domestic federal statutory income tax rate to pretax income (loss) from continuing operation, attributable to expense for award under share-based payment arrangement. Excludes expense determined to be nondeductible upon grant or after for award under share-based payment arrangement.

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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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The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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