Income Taxes (Tables)

12 Months Ended

Dec. 31, 2021

Income Tax Disclosure [Abstract]

Schedule of Components of Income (Loss) Before Income Taxes

The components of income (loss) before income taxes were as follows:

	Years Ended December 31,
	2021			2020			2019
	(in thousands)
United States	$	32,379		$	(9,645	)	$	(6,485	)
Foreign		(24	)		274			(130	)
	$	32,355		$	(9,371	)	$	(6,615	)

Schedule of Components of Income Tax (Expense) Benefit

The components of income tax (expense) benefit were as follows:

	Years Ended December 31,
	2021			2020			2019
	(in thousands)
United States	$	(12	)	$	(1	)	$	8
Foreign		(66	)		—			—
	$	(78	)	$	(1	)	$	8

Schedule of Components of Deferred Tax Assets and Liabilities

The material components of the deferred tax assets and liabilities consisted of net operating loss carry-forwards and tax credit carry-forwards.

	Years Ended December 31,
	2021			2020			2019
	(in thousands)
Deferred tax assets (liabilities):
Accrual, write-down and other	$	5,442		$	3,249		$	2,469
Depreciation and amortization		(818	)		257			76
Net operating loss and credits carry forwards		64,690			52,445			42,949
Total gross deferred tax assets (liabilities)		69,314			55,951			45,494
Valuation allowance		(69,314	)		(55,951	)		(45,494	)
Total net deferred tax assets	$	—		$	—		$	—

Schedule of Reconciliation of Effective Tax Rate

A reconciliation of the Company’s effective tax rate to the statutory U.S. federal rate is as follows:

	Years Ended December 31,
	2021			2020			2019
	(in thousands)
US Federal Rate		21.0	%		21.0	%		21.0	%
R&D Credits		-			-			(10.9	)
Permanent differences and others		(63.3	)		90.4			(18.3	)
Change in valuation allowance		42.3			(111.4	)		8.2
		0.0	%		0.0	%		0.0	%

Schedule of Reconciliation of Unrecognized Tax Benefit

A reconciliation of the beginning and ending unrecognized tax benefit amount is as follows:

	December 31,
	2021			2020
	(in thousands)
Beginning balance	$	2,436		$	2,184
Increase (decrease) in balance related to tax position taken during prior periods		—			—
Increase (decrease) in balance related to tax position taken during the current period		(5	)		252
Ending balance	$	2,431		$	2,436

Schedule of Tax Years Examination By Major Tax Jurisdictions

As of December 31, 2021, the tax years that remain subject to examination by the major tax jurisdictions under the statute of limitations are as follows:

Jurisdiction	Earliest Tax Year Subject to Examination
U.S. federal	2018
California State	2017
Michigan State	2017