Income Taxes (Tables)

12 Months Ended

Dec. 31, 2019

Income Tax Disclosure [Abstract]

Schedule of Components of Deferred Tax Assets and Liabilities

The significant components of our deferred tax assets and liabilities for the periods presented are as follows (in thousands):

	December 31,
	2019			2018
Deferred tax assets
Net operating losses	$	79,035		$	56,555
Tax credit carryforward		11,152			6,709
Non qualifying stock options		9,150			7,861
Deferred rent		11,755			1,925
Other		3,598			2,598
Total deferred tax assets		114,690			75,648
Valuation allowance		(100,906	)		(70,722	)
Deferred tax assets, net of valuation allowance		13,784			4,926
Deferred tax liabilities
Tangible and intangible assets		(13,784	)		(4,926	)
Net deferred taxes	$	—		$	—

Schedule of Reconciliation of Effective Tax Rate of Provision for Income Taxes Differs from Federal Statutory Rate

The effective tax rate of our provision for income taxes differs from the federal statutory rate for the periods presented as follows:

	Year Ended December 31,
	2019			2018			2017
Statutory rate		21.0	%		21.0	%		34.0	%
State tax		8.1			5.5			1.8
Stock compensation		9.8			0.5			(1.7	)
Permanent items		(1.0	)		0.5			(0.1	)
Credits		6.1			2.7			2.7
TCJA change in federal rate		—			—			(58.4	)
Other		0.3			0.1			(0.6	)
Change in valuation allowance		(44.3	)		(30.3	)		22.3
Total		0.0	%		0.0	%		0.0	%

Schedule of Change in Unrecognized Tax Benefits

A reconciliation of the beginning and ending amounts of unrecognized tax benefits during the years ended December 31, 2019, 2018 and 2017 are as follows (in thousands):

Balance at December 31, 2016	$	844
Additions in 2017		187
Balance at December 31, 2017		1,031
Additions in 2018		229
Balance at December 31, 2018		1,260
Additions in 2019		792
Balance at December 31, 2019	$	2,052