Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Schedule of Geographical Breakdown of Loss Before Provision for Income Taxes

The geographical breakdown of loss before provision for income taxes is as follows:

	Year Ended December 31,
	2020			2019			2018
	(in thousands)
United States	$	(81,670	)	$	(89,459	)	$	(54,395	)
International	$	910			1,024			758
Loss before provision for (benefit from) income    taxes, net	$	(80,760	)	$	(88,435	)	$	(53,637	)

Components of Provision (Benefit from) for Income Taxes

The components of the provision for (benefit from) income taxes are as follows:

	Year Ended December 31,
	2020		2019			2018
	(in thousands)
Current tax provision (benefit):
Federal	$	—	$	—		$	—
State		—		—			—
Foreign		59		85			(180	)
Total current tax provision (benefit)	$	59	$	85		$	(180	)
Deferred tax provision (benefit):
Foreign		83		(245	)		(122	)
Total deferred tax provision (benefit)	$	83	$	(245	)	$	(122	)
Total provision for (benefit from)    income taxes	$	142	$	(160	)	$	(302	)

Reconciliation Between Income Taxes Computed at the Federal Statutory Income Tax Rate and the Provision for Income Taxes

The reconciliation between income taxes computed at the federal statutory income tax rate and the provision for (benefit from) income taxes is as follows:

	Year Ended December 31,
	2020			2019			2018
Federal statutory rate		21.0	%		21.0	%		21.0	%
Effect of:
Change in valuation allowance		(23.6	)		12.4			(22.2	)
Federal tax credit		5.8			1.5			2.4
Warrant issuance and remeasurement		(4.2	)		(5.3	)		—
Effect of ownership change on deferred tax assets		1.3			(29.0	)		—
State income tax benefit, net of federal benefit		0.2			0.2			0.3
Other permanent items		(0.7	)		(0.6	)		(1.0	)
Total provision for (benefit from) income    taxes%		(0.2	)%		0.2	%		0.5	%

Components of the Deferred Tax Assets

The components of the deferred tax assets are as follows:

	December 31,
	2020			2019
	(in thousands)
Deferred tax assets:
Net operating loss carryforwards	$	14,011		$	2,649
Stock based compensation		6,459			4,663
59 (e) expenditures and amortization		6,222			5,902
Federal R&D and orphan drug credits		5,107			486
License fee		3,224			2,538
Other		1,024			967
Gross deferred tax assets		36,047			17,205
Valuation allowance		(35,513	)		(16,441	)
Total deferred tax assets		534			764
Deferred tax liabilities:
Lease Asset		114			244
Other		73			90
Total deferred tax liabilities		187			334
Total net deferred tax assets	$	347		$	430

Unrecognized Tax Benefits

The activity related to the gross amount of unrecognized tax benefits is as follows:

	Year Ended December 31,
	2020			2019			2018
	(in thousands)
Beginning balance	$	314		$	264		$	43
Increases based on tax positions related to prior    years		—			—			109
Decreases based on tax positions related to prior    years		(54	)		(103	)		—
Decreases due to ownership change		(207	)		—			—
Increases based on tax positions in current year		568			153			112
Settlement		—			—			—
Lapse of statute of limitations		—			—			—
Ending balance	$	621		$	314		$	264