Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2017	Dec. 31, 2018
Income Taxes [Line Items]
Benefit related to a change in enacted tax law		$ 8,276
Statutory federal rate	21.00%
Net operating loss carryforwards	$ 8,600		$ 18,700
Net operating loss carryforwards expiration year	2031
Net operating loss carryforwards, valuation allowance	$ 2,800		5,200
Income tax examination description	We are routinely under audit by federal or state authorities. Our federal tax returns are subject to examination by the IRS for tax years after 2015. We are subject to examination by most state tax jurisdictions for tax years after 2015.
Research Tax Credit Carryforward [Member]
Income Taxes [Line Items]
Tax credit carryforward amount	$ 5,200		4,000
Tax credit carryforward expiration year	2030
State and Local Jurisdiction [Member]
Income Taxes [Line Items]
Net operating loss carryforwards	$ 8,800		8,800
Net operating loss carryforwards expiration year	2031
Tax credit carryforward amount	$ 200		$ 200
Tax credit carryforward expiration year	2027
Income tax examination year	2015
State and Local Jurisdiction [Member] | NEW YORK [Member]
Income Taxes [Line Items]
Effective income tax rate continuing operations	0.00%
Federal [Member] | IRS [Member]
Income Taxes [Line Items]
Income tax examination year	2015