Income Taxes (Tables)

12 Months Ended

Dec. 31, 2018

Income Taxes

Schedule of components of income (loss) before income taxes

	Year Ended December 31,
	2018		2017		2016
United States	$	(31,436)	$	(27,019)	$	(23,173)
Foreign		(75)		—		—
	$	(31,511)	$	(27,019)	$	(23,173)

Schedule of provision for (benefit from) income taxes

	Year Ended December 31,
	2018		2017		2016
Current:
United States
Federal	$	—	$	—	$	—
State		18		—		—
Foreign		—		—		—
Total current income tax provision		18		—		—
Deferred
United States
Federal		2		—		—
State		5		—		—
Foreign		—		—		—
Total deferred income tax provision (benefit)		7		—		—
Total income tax provision (benefit)	$	25	$	—	$	—

Schedule of reconciliation of the federal statutory income tax rate to the effective tax rate

A reconciliation of the federal statutory income tax rate to the effective tax rate is as follows:

	Year Ended December 31,
	2018		2017
Federal statutory income tax rate	21.0	%	34.0	%
State taxes, net of federal tax benefit	6.0	%	4.8	%
Stock compensation	1.1	%	0.0	%
Permanent items	(1.2)	%	(1.6)	%
Tax Credits	2.7	%	2.6	%
Foreign differential	0.0	%	0.0	%
U.S. Tax Reform	0.0	%	(53.2)	%
Other, net	0.2	%	(1.1)	%
Valuation Allowance	(29.9)	%	14.5	%
Effective income tax rate	(0.1)	%	0.0	%

Schedule of deferred tax assets and liabilities

	December 31,
	2018		2017
Deferred tax assets:
Net operating loss carryforwards	$	35,623	$	27,952
Research and development credits		4,678		3,637
Deferred revenue		1,614		1,795
Depreciation		86		629
Amortization		792		—
Stock compensation		541		185
Other deferred tax assets		1,378		614
Total deferred tax assets		44,712		34,812
Valuation allowance		(44,033)		(34,552)
Subtotal		679		260
Section 481(a) Adjustment - Accrued Bonus		(59)		(118)
Amortization		(610)		—
Goodwill		(17)
Stock-based compensation		—		(142)
Net deferred tax assets (liability)	$	(7)	$	—