Income Taxes - Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Income Taxes
Deferred revenue	$ 9	$ 21
Basis difference in intangible assets	1,319	2,994
Inventory reserve	2,377	2,434
Net operating loss carryforwards	7,121	3,605
Research and development tax credits	1,579	1,272
Accrued expenses	43	61
Stock-based compensation	308	309
Allowance for sales returns and doubtful accounts	83	128
Difference in property and equipment basis	(124)	(145)
Other	469	479
Total net deferred income tax asset	13,184	11,158
Less: Valuation allowance	(13,184)	(11,158)
Net deferred income tax asset (liability)

Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from deferred income.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from intangible assets including goodwill.

+ References

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 2
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from inventory.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary differences, classified as other.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible research tax credit carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from accrued liabilities.

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Amount, before allocation of valuation allowance, of deferred tax asset attributable to deductible temporary difference from allowance for credit loss on accounts receivable.

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- Definition

Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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Amount of deferred tax liability attributable to taxable temporary differences from property, plant, and equipment.

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