12. Income tax (expense) benefit

Loss before income taxes attributable to domestic and international operations, consists of the following:

	Year ended December 31
(in thousands)	2015			2016			2017
Domestic	$	(46,300	)	$	(54,509	)	$	(66,109	)
Foreign		(1,109	)		(1,053	)		(6,892	)

Loss before income taxes	$	(47,409	)	$	(55,562	)	$	(73,001	)

Income tax (expense) benefit consists of the following:

	Year ended December 31
(in thousands)	2015			2016			2017
Current tax
Domestic	$	(3	)	$	(4	)	$	—
Foreign		(172	)		(118	)		55
Deferred tax
Domestic		—			—			—
Foreign		620			794			(1,410	)

Total income tax (expense) benefit	$	445		$	672		$	(1,355	)

The reconciliation to our effective tax rate from the Austrian statutory income tax rate of 25% for the years ended December 31, 2015 and 2016 and from the Irish statutory income tax rate of 12.5% for the year ended December 31, 2017 is as follows:

	Year ended December 31
(% of pre-tax income)	2015			2016			2017
Statutory income tax rate		25.0	%		25.0	%		12.5	%
Non-deductible expenses		(0.1	)		(0.2	)		(0.8	)
Income not subject to tax		1.9			2.8			0.9
Impairment		—			—			1.4
Tax credits		—			0.4			0.2
Foreign rate differential		(5.0	)		(2.5	)		21.0
Other		0.2			0.2			(1.4	)
Valuation allowance		(21.1	)		(24.5	)		(35.6	)

Effective income tax rate		0.9	%		1.2	%		(1.8	)%

The following table summarizes the components of deferred income tax balances:

(in thousands)	2016			2017
Deferred tax assets:
Net operating loss carryforwards	$	54,220		$	70,871
Tax loss on liquidation of subsidiary		—			7,846
Equity compensation		1,025			1,450
Non-deductible reserves		409			57

Total deferred tax assets		55,654			80,224

Valuation allowance		(54,114	)		(80,087	)

Net deferred tax assets		1,540			137

Deferred tax liabilities:
Financial liabilities		95			80
Property, plant and equipment		35			57

Total deferred tax liability		130			137

Deferred tax, net	$	1,410		$	—

The table below summarizes changes in the deferred tax valuation allowance:

	Year ended December 31,
(in thousands)	2015			2016			2017
Balance at beginning of year	$	(30,507	)	$	(40,487	)	$	(54,114	)
Tax benefit		(9,980	)		(13,627	)		(25,973	)
Balance at end of year	$	(40,487	)	$	(54,114	)	$	(80,087	)

The following table summarizes carryforwards of net operating losses as of December 31, 2017.

(in thousands)	Amount		Expiration
Ireland	$	27,490	Indefinite
Austria	$	268,285	Indefinite
United States	$	200	2037

Due to uncertainty regarding the ability to realize the benefit of deferred tax assets primarily relating to net operating loss carryforwards, valuation allowances have been established to reduce deferred tax assets to an amount that is more likely than not to be realized.

On the basis of this evaluation, as of December 31, 2017, 2016 and 2015, the Company has recorded a valuation allowance of $80,087, $54,114 and $40,487, respectively, to recognize only the portion of the deferred tax asset that is more likely than not to be realized. The amount of the deferred tax asset considered realizable, however, could be adjusted if estimates of future taxable income during the carryforward period are reduced or increased or if objective negative evidence in the form of cumulative losses is no longer present and additional weight is given to subjective evidence such as our projections for growth.

The Tax Cuts and Jobs Act (the "TCJA") was enacted on December 22, 2017 and became effective January 1, 2018. The Tax Act had significant changes to U.S. tax law, lowering U.S. corporate income tax rates, implementing a territorial tax system, and modified the taxation of other income and expense items.

The TCJA reduces the U.S. corporate income tax rate from 35% to 21%, effective January 1, 2018. Deferred tax assets and liabilities are measured using enacted tax rates expected to apply to taxable income in the years in which those temporary differences are expected to reverse. As a result of the reduction in the U.S. corporate income tax rate from 35% to 21% under the TCJA, the Company revalued the ending net deferred tax assets and liabilities of its U.S. subsidiary as of December 31, 2017. The tax impact of the revaluation of these deferred tax assets, net was $0.8 million, which was wholly offset by a corresponding reduction in the valuation allowance for these net deferred tax assets resulting in a no net impact to income tax expense.

At December 31, 2017 and 2016, the Company had no uncertain tax positions and does not expect any material increase or decrease in income tax expense related to examinations or changes in uncertain tax positions.

The Company files income tax returns in Ireland. In addition, the Company's foreign subsidiaries file separate income tax returns in Austria and the United States and state jurisdictions in which they are located. Tax years 2012 and forward remain open for examination for Austrian tax purposes and years 2014 and forward remain open for examination for United States tax purposes.

The Company's policy is to record interest and penalties related to tax matters in income tax expense.