
	2020		2019
Current:
Federal	$	—	$	(21,697)
State	(214)		(1,899)
Foreign	(1)		42
Total current	(215)		(23,554)

Deferred:
Federal	259		(210)
State	293		(347)
Foreign	—		—
Total deferred	552		(557)
	$	337	$	(24,111)

Deferred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred taxes at December 31, 2020 and 2019 are as follows:


	2020		2019
Deferred tax assets:
Net operating losses	$	11,570	$	8,004
Research and development credit carryforwards	3,246		3,104
Minimum tax credit carryforwards	—		31
Disallowed interest expense carryforwards	54		—
Stock compensation	258		168
Deferred revenue	148		588
Accrued expenses	590		349
Lease liabilities	1,931		1,905
Goodwill	—		2,132
Other	303		347
	18,100		16,628
Valuation allowance	(6,892)		(5,204)
Net deferred tax assets	11,208		11,424

Deferred tax liabilities:
Acquired intangibles	(5,930)		(7,828)
Fixed assets	(284)		(125)
Capitalized software	(1,524)		(1,353)
Deferred commission	(1,000)		(698)
Right-of-use asset	(1,721)		(1,756)
Goodwill	(1,637)		—
	(12,096)		(11,760)
Net deferred liabilities	$	(888)	$	(336)

At December 31, 2020, we had federal net operating loss carryforwards of approximately $48,435, research and development credit carryforwards of approximately $3,579. The net operating loss and research and development credit carryforwards will expire in varying amounts from 2021 through 2040, if not utilized. Approximately $16,962 of the net operating loss carryforwards carry forward indefinitely, but can only offset up to 80% of taxable income.

As a result of various acquisitions by us in prior years, we may be subject to a substantial annual limitation in the utilization of the net operating losses and credit carryforwards due to the “change in ownership” provisions of Section 382 of the Internal Revenue Code of 1986. The annual limitation may result in the expiration of net operating losses before utilization.

Due to the uncertainty surrounding the timing of realizing the benefits of our favorable tax attributes in future tax returns, we have placed a valuation allowance against our net deferred tax assets, exclusive of jurisdictions in which we have net deferred tax liabilities. During the year ended December 31, 2020, the valuation allowance increased by approximately $1,688 due primarily to operations.

Our provision for income taxes attributable to continuing operations for the years ended December 31, 2020 and 2019 differ from the expected tax expense (benefit) amount computed by applying the statutory federal income tax rate of 21% to income before income taxes as a result of the following:


	2020		2019
Computed at statutory rate	$	(3,355)	$	(13,944)
State taxes, net of federal benefit	(632)		(1,901)
Permanent items and other	(379)		992
Credit carryforwards	(122)		2,014
Foreign income taxed at different rates	—		22
Goodwill impairment	—		3,907
Change in tax carryforwards not benefitted	3,137		(352)
Change in valuation allowance	1,688		(14,849)
	$	337	$	(24,111)

Under ASC 740-10, Income Taxes, we periodically review the uncertainties and judgments related to the application of complex income tax regulations to determine income tax liabilities in several jurisdictions. We use a “more likely than not” criterion for recognizing an asset for unrecognized income tax benefits or a liability for uncertain tax positions. We have determined we have the following unrecognized assets or liabilities related to uncertain tax positions as of December 31, 2020. We do not anticipate any significant changes in such uncertainties and judgments during the next twelve months. To the extent we are required to recognize interest and penalties related to unrecognized tax liabilities, this amount will be recorded as an accrued liability. The reconciliation of our unrecognized tax benefits is as follows:


Balance at December 31, 2018	$	1,435
Additions based on tax positions related to the current year	106
Additions for tax positions of prior years	59
Reductions for tax positions of prior years	(744)
Balance at December 31, 2019	$	856
Additions based on tax positions related to the current year	(232)
Additions for tax positions of prior years	19
Reductions for tax positions of prior years	(56)
Balance at December 31, 2020	$	587

As of December 31, 2020, we had $587 of unrecognized tax benefits, of which $15 would affect the effective tax rate if recognized. Our assessment of our unrecognized tax benefits is subject to change as a function of our financial statement audit.

Our practice is to recognize interest and/or penalties related to income tax matters in income tax expense. During the twelve months ended December 31, 2020, we recognized $0 of interest and penalties in our income tax expense.