	Year Ended
	December 31,
	2018		2017			2016
Current portion:
State	$	2	$	3		$	3
Foreign		11		7			42
		13		10			45
Deferred portion:
Federal		—		(243	)		—
	$	13	$	(233	)	$	45

In December 2017, the Tax Cuts and Jobs Act (“the Act”) was signed into law making significant changes to the Internal Revenue Code of 1986, as amended (the “IRC”). Changes included, but are not limited to, reducing the U.S. federal corporate tax rate from 35.0% to 21.0% as of January 1, 2018 and repealing the alternative minimum tax (“AMT”) for tax years beginning in 2018.

Income tax effects resulting from changes in tax laws are accounted for by the Company in accordance with the authoritative guidance, which requires that these tax effects be recognized in the period in which the law is enacted and the effects are recorded as a component of provision for income taxes from continuing operations.

Under the Act, $0.2 million in federal AMT tax paid by the Company for 2011 is now refundable through 2022 subject to limitations by year, and was recorded as a deferred tax asset in 2017.

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amount of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes.

Significant components of the Company’s deferred tax assets and liabilities were (in thousands):

	Year Ended
	December 31,
	2018			2017
Deferred tax assets:
Federal and state loss carryforwards	$	681		$	49,533
Reserves, accruals and other		230			391
Depreciation and amortization		1,901			1,100
Deferred stock-based compensation		2,571			2,483
Research and development credit carryforwards		6,537			15,487
Foreign tax and other credits		242			513
Total deferred tax assets		12,162			69,507
Deferred tax liabilities:
Acquired intangible assets and other		—			408
Less: Valuation allowance		(11,920	)		(68,857	)
Net deferred tax assets	$	242		$	242

The valuation allowance decreased by $20.6 million for the year ended December 31, 2017. The $56.9 million decrease in valuation allowance for the year ended December 31, 2018 was primarily the result of the significant reduction of the deferred tax assets previously recognized related to the utilization of net operating loss and tax credit carryforwards.

Utilization of the Company’s net operating losses (“NOLs”) and tax credit carryforwards is subject to a substantial annual limitation due to the ownership change limitations provided by the IRC and similar state provisions. Section 382 of the IRC (“Section 382”) imposes limitations on a corporation’s ability to utilize its NOL and tax credit carryforwards, if it experiences an “ownership change.” In general terms, an ownership change may result from transactions increasing the ownership percentage of certain stockholders in the stock of the corporation by more than 50% over a three-year period. In the event of an ownership change, utilization of the NOLs would be subject to an annual limitation under Section 382 determined by multiplying the value of the Company’s stock at the time of the ownership change by the applicable long-term tax-exempt rate. While a formal study has not been performed, the Company believes that a Section 382 ownership change occurred as a result of the financing effected in October 2018 (see Note 6). The Company believes this Section 382 limitation will result in approximately 98% of the federal and state NOLs expiring before they can be utilized, and approximately 100% of the federal tax credit carryforwards expiring before they can be utilized.

As of December 31, 2018, the Company had NOLs of approximately $196.4 million for federal income tax purposes and approximately $119.9 million for state income tax purposes. Only approximately $2.5 million of the federal NOLs and $2.2 million of the state NOLs are expected to be available before expiration due to the Section 382 limitation. These NOLs are available to reduce future taxable income and expire at various times from 2025 through 2037.

The Company also had federal research and development tax credit carryforwards of approximately $9.0 million, which will begin expiring in 2019, and California research and development credits of approximately $8.2 million, which do not have an expiration date.

A reconciliation of income taxes provided at the federal statutory rate (21% for 2018 and 35% for each of 2017 and 2016) to the actual income tax provision is as follows (in thousands):

	Year Ended
	December 31,
	2018			2017			2016
Income tax benefit computed at U.S. statutory rate	$	(2,393	)	$	(3,815	)	$	(11,229	)
State income tax (net of federal benefit)		2			3			3
Foreign income tax at rate different from U.S. statutory rate		12			3			(7	)
Research and development credits		(194	)		(480	)		(981	)
Stock-based compensation		—			(40	)		75
Amortization of intangible assets		(60	)		(100	)		(100	)
Goodwill impairment		1,482			—			1,856
Federal tax rate reduction		—			(26,617	)		—
Valuation allowance changes affecting tax provision		1,158			30,811			10,022
Other		6			2			406
Income tax (benefit) provision	$	13		$	(233	)	$	45

The domestic and foreign components of loss before income tax provision were (in thousands):

	Year Ended
	December 31,
	2018			2017			2016
U.S.	$	(11,353	)	$	(11,063	)	$	(31,115	)
Non-U.S.		(43	)		162			(888	)
	$	(11,396	)	$	(10,901	)	$	(32,003	)