Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Tax Disclosure [Abstract]

Schedule of Reconciliation between U.S. Federal Statutory Tax Rate and Effective Tax Rate

A reconciliation between the U.S. federal statutory tax rate and the Company’s effective tax rate is summarized as follows:

	For the Years Ended December 31,
	2018			2017
Federal statutory rate		21.0	%		34.0	%
Tax credits		17.7	%		4.8	%
State taxes, net of federal tax benefit		5.5	%		5.0	%
Change in tranche liability		—	%		(1.0	%)
Non-deductible expenses		(0.3	%)		(1.8	%)
Impact of federal rate change		—	%		(15.2	%)
Change in valuation allowance		(43.9	%)		(25.8	%)
Effective income tax rate		—	%		—	%

Schedule of Deferred Tax Assets and Liabilities

The principal components of the Company’s deferred tax assets and liabilities consist of the following:

	December 31,
	2018			2017
	(in thousands)
Deferred tax assets:
Net operating losses	$	14,848		$	9,180
R&D credits		12,506			1,776
Deferred revenue		8,159			—
Deferred rent		2,854			113
Capitalized R&D costs		1,375			1,362
Equity compensation		443			27
Accrued expense and other		115			196
Total deferred tax assets		40,300			12,654
Deferred tax liabilities:
Depreciation		(2,680	)		(166	)
Total deferred tax liabilities		(2,680	)		(166	)
Valuation allowance		(37,620	)		(12,488	)
Net deferred taxes	$	—		$	—