Income Taxes (Details 3) - USD ($)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Gross unrecognized tax benefits beginning balance	$ 450,000	$ 493,000	$ 865,000
Increase in tax positions for prior years	8,000	19,000	25,000
Increase in tax positions for current year	0	0	0
Lapse in statutes of limitation	(458,000)	(62,000)	(397,000)
Gross unrecognized tax benefits ending balance	$ 0	$ 450,000	$ 493,000

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Amount of unrecognized tax benefits.

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Amount of increase in unrecognized tax benefits resulting from tax positions that have been or will be taken in current period tax return.

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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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Amount of decrease in unrecognized tax benefits resulting from lapses of applicable statutes of limitations.

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