Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Tax Disclosure [Abstract]

Summary of Reconciliation of Income Tax Expense (Benefit)

A reconciliation of income tax expense (benefit) to the amount computed by applying the statutory federal income tax rate to the loss from operations is summarized for the years ended December 31, 2020 and 2019, respectively, as follows (in thousands):

	Year Ended December 31,
	2020		2019
Income tax benefit at statutory rate	$	(20,699)	$	(8,242)
State income tax, net of federal benefit	(6,823)		(3,783)
Permanent items	8		16
Stock-based compensation	215		56
Orphan drug credit	(2,544)		(925)
Research and development credits	(863)		(763)
Uncertain tax positions	785		548
Change in state rate	74		(34)
Change in valuation allowance	28,090		13,179
Other	1,757		(52)
	$	—	$	—

Significant Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets as of December 31, 2020 and 2019 are shown below (in thousands):

	As of December 31,
	2020		2019
Deferred tax assets:
Net operating loss carryforwards	$	51,398	$	42,872
Research and development and orphan drug credits	8,662		6,212
Accrued expenses	936		519
Intangibles	43		60
Operating lease liabilities	562		545
Derivative liability	16,700		—
Other, net	628		322
Total deferred tax assets	78,929		50,530
Deferred tax liabilities:
Operating lease right-of-use assets	(540)		(527)
Property and equipment, net	(324)		(28)
Total deferred tax liabilities	(864)		(555)
Net deferred tax assets before valuation allowance	78,065		49,975
Valuation allowance	(78,065)		(49,975)
Net deferred tax assets	$	—	$	—

Summary of Activity Related to Gross Unrecognized Tax Benefits

The following table summarizes the activity related to the Company’s gross unrecognized tax benefits for the years ended December 31, 2020 and 2019 (in thousands):

	Year Ended December 31
	2020		2019
Gross unrecognized tax benefits at the beginning of the year	$	2,560	$	1,809
Increases related to current year positions	871		645
Increases related to prior year positions	—		106
Decreases related to prior year positions	(86)		—
Expiration of unrecognized tax benefits	—		—
Gross unrecognized tax benefits at the end of the year	$	3,345	$	2,560