The income tax benefit attributable to continuing operations during the years ended December 31, 2018, 2017 and 2016 is as follows:

For the years ended December 31,	2018			2017			2016
(dollars in thousands)
Current (benefit) provision
Federal	$	(1	)	$	(28	)	$	8
State		86			21			5
Deferred provision (benefit)
Federal		2,100			114			(3,501	)
State		(250	)		568			(38	)
Benefit related to a change in enacted tax law		-			(8,276	)		-
Provision (benefit) for income taxes	$	1,935		$	(7,601	)	$	(3,526	)

The income tax provision (benefit) reconciled to taxes computed at the statutory federal rate is as follows:

For the years ended December 31,		2018				2017				2016
Tax provision (benefit) at statutory tax rate	$		2,645		$		3		$		(3,106	)
State income taxes, net of federal impact			74				3				(39	)
Research and development tax credit			(874	)			(425	)			(439	)
Valuation allowance, net of federal impact			(167	)			475				-
Impact of changes in enacted tax law			-				(8,276	)			-
Adjustments to deferred taxes			277				506				4
Other, net			(20	)			113				54
Provision (benefit) for income taxes	$		1,935		$		(7,601	)	$		(3,526	)

We continue to record a full valuation allowance against our New York deferred tax assets due to the zero percent state income tax rate for qualified manufacturers. We continue to record a partial valuation allowance against our Pennsylvania net operation loss deferred tax asset due to annual usage limitations. We have determined that federal and other state deferred tax assets are expected to be realized and have not recorded any additional valuation allowances.

We recognized the tax effects of the Tax Cuts and Jobs Act (the “Tax Act”) in the year ended December 31, 2017 and recorded $8.3 million in tax benefits, which relates almost entirely to the remeasurement of deferred tax liabilities to the reduced 21% corporate income tax rate.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our net deferred taxes related to continuing operations are as follows:

December 31,	2018		2017
(dollars in thousands)
Noncurrent deferred income taxes:
Federal and state tax carryforwards	$	8,331	$	12,894
Inventory		787		549
Share-based compensation		1,909		2,186
Receivables		239		194
Accrued liabilities		836		349
Other		5		32
Total deferred tax assets	$	12,107	$	16,204
Deferred tax liabilities:
Property, plant and equipment	$	22,951	$	24,970
Other		637		839
Total deferred tax liabilities	$	23,588	$	25,809
Total noncurrent deferred income taxes	$	11,481	$	9,605

We file a U.S. federal income tax return and various state income tax returns. For federal income tax purposes, we had $18.7 million and $45.0 million of net operating loss carryforwards at December 31, 2018 and 2017, respectively. The net operating loss carryforwards begin to expire in 2031. In addition, we have credit carryforwards associated with our research and development activities of $4.0 million and $3.1 million as of December 31, 2018 and 2017, respectively. The research and development credit carryforwards begin to expire in 2030.

We have state net operating loss carryforwards of $8.8 million and $9.1 million, of which $5.2 million and $7.4 million, respectively, have a valuation allowance, and state credit carryforwards of $0.2 million at December 31, 2018 and 2017. The state net operating loss carryforwards begin to expire in 2031. The state credit carryforwards begin to expire in 2027.

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 2014. We are subject to examination by most state tax jurisdictions for tax years after 2014.