The Company was subject to taxes in both the U.S. and Switzerland in each of the years in the three-year period ended December 31, 2020. Income (loss) before income taxes was derived from the following jurisdictions:

	2020			2019			2018
U.S.	$	10,284		$	(1,734	)	$	(6,696	)
Switzerland		(363	)		(293	)		181
	$	9,921		$	(2,027	)	$	(6,515	)

The income tax expense (benefit) for the years ended December 31, 2020, 2019 and 2018 was comprised of:

	2020			2019		2018
Current:
Federal	$	—		$	—	$	—
State		700			—		—
Foreign		2			—		—
Total current		702			—		—
Deferred:
Federal		(39,542	)		—		—
State		(7,440	)		—		—
Foreign		—			—
Total deferred		(46,982	)		—		—
Total income tax benefit	$	(46,280	)	$	—	$	—

Effective tax rates differ from statutory income tax rates in the years ended December 31, 2020, 2019 and 2018 as follows:

	2020			2019			2018
Statutory income tax rate		21.0	%		21.0	%		21.0	%
State income taxes		7.1			14.4			3.8
Effect of foreign operations		0.2			(1.0	)		0.2
Changes in valuation allowance		(516.5	)		(59.9	)		(20.8	)
Change in unused net operating loss and credit carryforwards		—			24.7			3.9
Change in uncertain tax positions		21.4			—			—
Research and development credit		(6.0	)		—			—
Stock-based compensation		3.7			22.3			0.2
162(m) limitation		1.9			(18.2	)		(2.9	)
Nondeductible items		1.6			(1.8	)		(3.2	)
Impact of Tax Cuts and Jobs Act		—			(1.5	)		(2.2	)
Other		(0.9	)		—			—
Effective income tax rate		(466.5	)%		0.0	%		0.0	%

Deferred tax assets (liabilities) as of December 31, 2020 and 2019 consist of the following:

	2020			2019
Gross deferred tax assets:
Net operating loss carryforward – U.S.	$	36,071		$	41,780
Net operating loss carryforward – Switzerland		106			52
Research and development tax credit carryforward		5,418			7,559
Deferred revenue		219			—
Stock-based compensation		2,954			1,999
Inventory reserve		159			307
Compensation accruals		1,304			1,154
Product reserves		2,820			2,329
Operating lease liabilities		1,546			1,763
163j interest expense limitation		—			475
Amortization		607			585
Other		145			61
Total deferred tax assets		51,349			58,064
Deferred tax liabilities:
Depreciation		(1,838	)		(1,807	)
Right-of-use asset, operating leases		(1,303	)		(1,648	)
Total deferred tax liabilities		(3,141	)		(3,455	)
Net deferred tax asset before valuation allowance		48,208			54,609
Less valuation allowance		(1,226	)		(54,609	)
Net deferred tax asset	$	46,982		$	—

In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which temporary differences become deductible or in which net operating loss or tax credit carryforwards can be utilized. As of each reporting date, management considers new evidence, both positive and negative, that could affect its view of the future realization of deferred tax assets.

After considering both positive and negative evidence with respect to the U.S. deferred tax assets, management determined that as of December 31, 2019, it was more likely than not that the U.S. deferred tax assets would not be realized and recorded a full valuation allowance against all U.S. deferred tax assets. As of December 31, 2020, management determined that, as a result of generating pretax earnings, utilization of net operating loss carryovers and projected pre-tax earnings, there is sufficient positive evidence to conclude that it is more likely than not that its U.S. deferred tax assets of $46,982 are realizable. For the year ended December 31, 2020, the Company recorded a net valuation allowance release of $53,383 based on management’s reassessment of the amount of its deferred tax assets that are more likely than not to be realized. The remaining valuation allowance of $1,226 as of December 31, 2020 relates to certain state and foreign carryovers for which projected income cannot support utilization.

The Company has a U.S. federal net operating loss carryforward at December 31, 2020 of $148,318, which, subject to limitations of Internal Revenue Code (“IRC”) Section 382, is available to reduce income taxes payable in future years. As of December 31, 2020, the Company has performed a full analysis of IRC Section 382 and concluded that net operating losses and credits will be able to be utilized without limitation. If not used, the portion of the carryforward generated before 2018 will expire in the years 2025 through 2037, and the net operating loss carryforward generated in 2018 and any future years will carry forward indefinitely. Additionally, the Company has U.S. Research Credit carryforwards of $6,985. These credits expire in years 2021 through 2040.

The Company also has a Swiss net operating loss carryforward at December 31, 2020, of $735, which is available to reduce income taxes payable in future years. If not used, this carryforward will begin to expire in 2023.

The reconciliation of the Company’s gross unrecognized tax benefits as of December 31, 2020 includes increases to prior year tax positions of $2,067 and current year positions of $60. The balance of gross unrecognized tax benefits at December 31, 2019 was $0. Included in the balance of unrecognized tax benefits as of December 31, 2020 and 2019, are $2,127 and $0, respectively, that if recognized would impact the effective tax rate. There is no interest or penalties charged or accrued in relation to unrecognized tax benefits. The Company will classify any future interest and penalties as a component of income tax expense. The Company does not anticipate that the total amount of unrecognized tax benefits will change significantly in the next twelve months. The Company is subject to federal and state examinations for the years 2016 and thereafter.