Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

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, 2018 and 2017, respectively, as follows (in thousands):

	Year Ended December 31,
	2018			2017
Income tax benefit at statutory rate	$	(5,008	)	$	(3,484	)
State income tax, net of federal benefit		(1,593	)		(528	)
Permanent items		3			4
Fair value adjustments		15			(164	)
Non-deductible interest expense		706			905
Stock-based compensation		45			21
Orphan drug credit		(475	)		(616	)
Research and development credits		(274	)		(218	)
Uncertain tax positions		222			209
Tax Cuts and Jobs Act		(15	)		10,978
Change in valuation allowance		6,426			(7,110	)
Other		(52	)		3
	$	—		$	—

Significant Components of Deferred Tax Assets

Significant components of the Company’s deferred tax assets as of December 31, 2018 and 2017 are shown below:

	Year Ended December 31,
	2018			2017
Net deferred tax asset:
Net operating loss carryforwards	$	31,744		$	26,138
Research and development credits		4,615			3,863
Accrued expenses		332			239
Intangibles		69			110
Property and equipment		(18	)		(2	)
Other, net		54			22
Total net deferred tax asset		36,796			30,370
Valuation allowance for deferred tax asset		(36,796	)		(30,370	)
Deferred tax assets, net of valuation allowance	$	—		$	—

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, 2018 and 2017 (in thousands):

	Year Ended December 31,
	2018		2017
Gross unrecognized tax benefits at the beginning of the year	$	1,293	$	1,067
Increases related to current year positions		362		226
Increases related to prior year positions		154		—
Decreases related to prior year positions		—		—
Expiration of unrecognized tax benefits		—		—
Gross unrecognized tax benefits at the end of the year	$	1,809	$	1,293