Income tax (expense) benefit (Tables)

12 Months Ended

Dec. 31, 2018

Income tax (expense) benefit

Schedule of loss before income taxes attributable to domestic and international operations

	Year ended December 31
(in thousands)	2016		2017		2018
Domestic	$	(54,509)	$	(66,109)	$	(113,699)
Foreign		(1,053)		(6,892)		(1,032)
Loss before income taxes	$	(55,562)	$	(73,001)	$	(114,731)

Schedule of income tax (expense) benefit

	Year ended December 31
(in thousands)	2016		2017		2018
Current tax
Domestic	$	(4)	$	—	$	—
Foreign		(118)		55		(49)
Deferred tax
Domestic		—		—		—
Foreign		794		(1,410)		—
Total income tax (expense) benefit	$	672	$	(1,355)	$	(49)

Schedule of effective income tax rate reconciliation

	Year ended December 31
(% of pre-tax income)	2016		2017		2018
Statutory income tax rate	25.0	%	12.5	%	12.5	%
Non-deductible expenses	(0.2)		(0.8)		(0.1)
Income not subject to tax	2.8		0.9		0.3
Impairment	—		1.4		—
Tax credits	0.4		0.2		0.1
Foreign rate differential	(2.5)		21.0		(3.1)
In-process research and development	—		—		(3.5)
Other	0.2		(1.4)		0.2
Valuation allowance	(24.5)		(35.6)		(6.5)
Effective income tax rate	1.2	%	(1.8)	%	(0.1)	%

Summary of the components of deferred income tax balances

	As of December 31,
(in thousands)	2017		2018
Deferred tax assets:
Net operating loss carryforwards	$	70,871	$	91,995
Tax loss on liquidation of subsidiary		7,846		6,245
Equity compensation		1,450		2,473
Non-deductible reserves		57		203
Total deferred tax assets		80,224		100,916
Valuation allowance		(80,087)		(100,832)
Net deferred tax assets		137		84
Deferred tax liabilities:
Financial liabilities		80		55
Property, plant and equipment		57		29
Total deferred tax liability		137		84
Deferred tax, net	$	—	$	—

Summary of changes in the deferred tax valuation allowance

	Year ended December 31,
(in thousands)	2016		2017		2018
Balance at beginning of year	$	(40,487)	$	(54,114)	$	(80,087)
Tax benefit		(13,627)		(25,973)		(7,301)
Acquired tax attributes		—		—		(13,444)
Balance at end of year	$	(54,114)	$	(80,087)	$	(100,832)

Summary of carryforwards of net operating losses

The following table summarizes carryforwards of net operating losses as of December 31, 2018.

(in thousands)	Amount		Expiration
Ireland	$	107,671	Indefinite
Austria	$	259,229	Indefinite
United States	$	44,728	2033