Income Taxes (Tables)

12 Months Ended

Dec. 31, 2020

Income Taxes

Summary of Significant components of the Company’s deferred tax assets

	December 31,
	2020		2019
Deferred tax assets
Net operating loss carryforwards	$	39,937	$	32,704
Research and development credits		747		853
Depreciation and amortization		239		578
Accrued expenses and other		611		259
Inventory reserve		205		417
Gross deferred tax asset		41,739		34,811
Valuation allowance		(41,739)		(34,811)
Net deferred tax asset	$	—	$	—

Schedule of Company’s net operating loss (NOL) carryforwards

	December 31,
	2020		2019
NOL carryforwards
Federal	$	150,642	$	122,925
State		128,912		106,062

Schedule of reconciliation of income tax benefit

	Year ended December 31,
	2020		2019		2018
Rate reconciliation
Federal tax benefit at statutory rate	(21.0)	%	(21.0)	%	(21.0)	%
State rate, net of federal benefit	(4.2)		(2.9)		(4.7)
Permanent differences	0.6		0.4		0.5
Research and development	0.7		(0.7)		(0.8)
Change in valuation allowance	24.0		24.2		26.3
Other	(0.1)		—		(0.3)
Total tax provision	—	%	—	%	—	%