Income Taxes (Tables)

12 Months Ended

Dec. 31, 2022

Income Tax Disclosure [Abstract]

Schedule of Income before Income Tax, Domestic and Foreign

Loss before the provision for income taxes for the years ended December 31, 2022, 2021 and 2020 consisted of the following:

	Year Ended December 31,
(in thousands)	2022		2021		2020
United States	$	(94,742)	$	(89,865)	$	(62,539)
Foreign (Austria)	903		1,186		556
	$	(93,839)	$	(88,679)	$	(61,983)

Schedule of Effective Income Tax Rate Reconciliation

A reconciliation of the U.S. federal statutory income tax rate to the Company's effective income tax rate is as follows:

	Year Ended December 31,
	2022		2021		2020
U.S. federal statutory income tax rate	(21.0)	%	(21.0)	%	(21.0)	%
State income taxes, net of federal benefit	(5.5)		(5.4)		(5.9)
Research and development tax credits	(1.0)		(0.9)		(1.1)
Other permanent differences	3.0		3.7		0.9
Change in deferred tax asset valuation allowance	23.2		23.7		27.2
Other	1.3		(0.1)		0.1
Effective income tax rate	—	%	—	%	0.2	%

Schedule of Deferred Tax Assets and Liabilities

Net deferred tax assets as of December 31, 2022 and 2021 consisted of the following:

	December 31,
(in thousands)	2022		2021
Net operating loss carryforwards	$	107,296	$	101,863
Research and development tax credit carryforwards	6,694		5,444
Capitalized research and development expenses	16,004		1,760
Lease liabilities	1,016		1,243
Other	3,604		3,372
Total deferred tax assets	134,614		113,682
Valuation allowance	(133,112)		(111,835)
Deferred tax assets, net of valuation allowance	$	1,502	$	1,847
Right of use assets	1,502		1,847
Total deferred tax liabilities	$	1,502	$	1,847
Total deferred tax assets, net	$	—	$	—

Summary of Valuation Allowance

Changes in the valuation allowance for deferred tax assets during the years ended December 31, 2022, 2021 and 2020 related primarily to the increases in net operating loss carryforwards and research and development tax credit carryforwards and were as follows:

	Year Ended December 31,
(in thousands)	2022		2021		2020
Valuation allowance, beginning of year	$	(111,835)	$	(92,197)	$	(73,410)
Increases recorded to income tax provision	(21,277)		(19,638)		(18,787)
Valuation allowance, end of year	$	(133,112)	$	(111,835)	$	(92,197)

Schedule of Unrecognized Tax Benefits Roll Forward

The following table summarizes the Company’s reserve for uncertain tax positions for the three years ended December 31, 2022:

(in millions)	Reserve for Uncertain Tax Position
Balance as of December 31, 2020	$	0.3
Settlement of unrecognized tax benefit	(0.1)
Balance as of December 31, 2021	0.2
Balance as of December 31, 2022	$	0.2