U.S and foreign components of consolidated loss before income taxes for the years ended December 31, 2019, 2018 and 2017, was as follows (in thousands):

	2019			2018			2017
Loss before income taxes:
U.S.	$	(71,946	)	$	(58,048	)	$	(57,925	)
Foreign		965			713			1,227
Loss before income taxes	$	(70,981	)	$	(57,335	)	$	(56,698	)

The provision for income taxes for the years ended December 31, 2019, 2018 and 2017, was as follows (in thousands):

	2019		2018		2017
Provision for income taxes:
Current:
Foreign	$	255	$	225	$	181
Federal		—		—		—
State		2		—		—
Total current		257		225		181
Deferred:
Foreign		—		—		—
Federal		4		3		3,659
State		2		1		47
Total deferred		6		4		3,706
Provision for income taxes	$	263	$	229	$	3,887

The difference between the provision for income taxes and the amount computed by applying the federal statutory income tax rate to loss before taxes for the years ended December 31, 2019, 2018 and 2017, was as follows (in thousands):

	2019			2018			2017
Federal statutory tax	$	(14,906	)	$	(12,040	)	$	(19,277	)
Tax Act revaluation of deferred taxes		—			—			81,923
Tax Act deemed income inclusion		—			—			1,083
Federal research credits		(1,857	)		(1,390	)		(1,000	)
State research credits		(821	)		(655	)		(628	)
Expiration of federal carryovers		5,472			4,154			—
Expiration of state carryovers		—			1,344			1,475
Change in valuation allowance		13,059			9,913			(59,462	)
Compensation related items		158			(361	)		1,382
State taxes		(1,111	)		(1,141	)		(803	)
Other		269			405			(806	)
Provision for income taxes	$	263		$	229		$	3,887

The Tax Cuts and Jobs Act (the “Tax Act”) resulted in a significant revaluation in the Company’s deferred tax balances as of the date of December 22, 2017, enactment due to the change in the statutory rate. In addition, all of the previously unremitted earnings of Cerus Europe B.V. were deemed to be distributed as of December 31, 2017, which resulted in a one-time deemed income inclusion.

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 at the enacted rates. The significant components of the Company’s deferred tax assets and liabilities at December 31, 2019 and 2018, were as follows (in thousands):

	December 31,
	2019			2018
Deferred tax assets:
Net operating loss carryforwards	$	135,536		$	125,016
Research and development credit carryforwards		28,291			26,705
Capitalized research and development		12,832			15,293
Compensation related items		9,843			8,310
Operating leases		4,374			—
Other		4,547			4,013
Total deferred tax assets		195,423			179,337
Valuation allowance		(192,304	)		(179,245	)
Net deferred tax assets	$	3,119		$	92

Deferred tax liabilities:
Right-of-use assets	$	3,017		$	—
Amortization of goodwill		143			127
Total deferred tax liabilities	$	3,160		$	127

The valuation allowance increased by $13.1 million for the year ended December 31, 2019, compared to the increase of $9.9 million and decrease of $59.5 million for the years ended December 31, 2018 and 2017, respectively. The Company believes that, based on a number of factors, the available objective evidence creates sufficient uncertainty regarding the realizability of the deferred tax assets such that a valuation allowance has been recorded. These factors include the Company’s history of net losses since its inception, the need for regulatory approval of the Company’s products prior to commercialization and expected near-term future losses. The Company expects to maintain a valuation allowance until circumstances change.

For the year ended December 31, 2019, the Company reported pretax net losses on its consolidated statement of operations and calculated taxable losses for both federal and state taxes. The difference between reported net loss and taxable loss are due to differences between book accounting and the respective tax laws.

The Company's tax losses and credits are subject to varying carryforward periods. The gross amounts and dates of expiration of the significant carryforwards are as follows:

			Expires		Expires		Expires		No
	Total		2020-2022		2023-2029		2030-2039		Expiration
Federal losses carryovers	$	616,915	$	64,730	$	186,421	$	239,731	$	126,033
California loss carryovers		67,781		—		14,732		53,049		—
Federal research credits		19,397		6,928		4,875		7,594		—
California research credits		11,259		—		—		—		11,259
Federal foreign tax credits		610		—		610		—		—

The Company’s ability to utilize net operating loss and research and development credit carryforwards is limited by (a) its ability to generate future taxable income, (b) varying apportionment and allocation rules including new provisions as part of the Tax Act, and (c) limitations pursuant to the ownership change rules in accordance with Section 382 of the Internal Revenue Code of 1986 and with Section 383 of the Internal Revenue Code of 1986, as well as similar state provisions.

The Company’s unrecognized tax benefits relate to federal and California research tax credits. These tax credits have not been utilized on any tax return and currently have no impact on the Company’s tax expense due to the Company’s operating losses and the related valuation allowances.

The following is a tabular reconciliation of the total amounts of unrecognized tax benefits (in thousands):

	December 31,			December 31,
	2019			2018
Unrecognized tax benefits at beginning of period	$	11,063		$	11,062
Decreases related to expired carryforwards		(729	)		(401	)
Increases related to current year tax positions		508			402
Unrecognized tax benefits at end of period	$	10,842		$	11,063

The Company will recognize accrued interest and penalties related to unrecognized tax benefits in its income tax expense. To date, the Company has not recognized any interest and penalties in its consolidated statements of operations, nor has it accrued for or made payments for interest and penalties.