Income tax expense (Tables)

12 Months Ended

Dec. 31, 2019

Income tax expense

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

	Year ended December 31
(in thousands)	2017		2018		2019
Domestic	$	(66,109)	$	(113,699)	$	(78,761)
Foreign		(6,892)		(1,032)		(3,902)
Loss before income taxes	$	(73,001)	$	(114,731)	$	(82,663)

Schedule of income tax expense

	Year ended December 31
(in thousands)	2017		2018		2019
Current tax
Domestic	$	—	$	—	$	—
Foreign		55		(49)		(101)
Deferred tax
Domestic		—		—		—
Foreign		(1,410)		—		—
Total income tax expense	$	(1,355)	$	(49)	$	(101)

Schedule of effective income tax rate reconciliation

	Year ended December 31
(% of pre-tax income)	2017		2018		2019
Statutory income tax rate	12.5	%	12.5	%	12.5	%
Non-deductible expenses	(0.8)		(0.1)		(0.1)
Income not subject to tax	0.9		0.3		0.3
Impairment	1.4		—		—
Tax credits	0.2		0.1		0.4
Foreign rate differential	21.0		(3.1)		0.6
In-process research and development	—		(3.5)		0.0
Tax audit assessments	—		—		(11.8)
Other	(1.4)		0.2		0.8
Valuation allowance	(35.6)		(6.5)		(2.8)
Effective income tax rate	(1.8)	%	(0.1)	%	(0.1)	%

Summary of the components of deferred income tax balances

	As of December 31,
(in thousands)	2018		2019
Deferred tax assets:
Net operating loss carryforwards	$	91,995	$	94,014
Tax loss on liquidation of subsidiary		6,245		5,024
Equity compensation		2,473		4,182
Non-deductible reserves		203		395
Total deferred tax assets		100,916		103,615
Valuation allowance		(100,832)		(103,185)
Net deferred tax assets		84		430
Deferred tax liabilities:
Financial liabilities		55		48
Property, plant and equipment		29		382
Total deferred tax liability		84		430
Deferred tax, net	$	—	$	—

Summary of changes in the deferred tax valuation allowance

	Year ended December 31,
(in thousands)	2017		2018		2019
Balance at beginning of year	$	(54,114)	$	(80,087)	$	(100,832)
Tax benefit		(25,973)		(7,301)		(2,353)
Acquired tax attributes		—		(13,444)		—
Balance at end of year	$	(80,087)	$	(100,832)	$	(103,185)

Summary of carryforwards of net operating losses

(in thousands)	Amount		Expiration
Ireland	$	187,631	Indefinite
Austria	$	223,827	Indefinite
United States	$	10,403	Indefinite
United States	$	35,680	2033