Income taxes - Elements of Deferred Income Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred income tax assets (liabilities)
- Depreciation & amortization	$ (4,899)	$ (5,865)
- Reserves for doubtful accounts	163	159
- Inventory reserve	2,083	2,503
- Non qualified stock options	965	778
- Net operating losses	11,016	9,574
- Amt credit	47	86
- Deferred interest	8,351	3,637
- Valuation allowance	(18,918)	(11,315)
Total	$ (1,192)	$ (443)

Deferred Tax Assets Tax Deferred Expense Reserves And Accruals Depreciation And Amortization.

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- Definition

It represents Deferred Tax Assets Tax Deferred Expense Reserves And Non Qualified Stock Options.

+ References

No definition available.

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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 operating loss carryforwards.

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

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from the allowance for doubtful accounts.

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

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

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Amount, after deferred tax asset, of deferred tax liability attributable to taxable differences without jurisdictional netting.

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