
	Year ended June 30,
	2021		2020		2019
Current:
Federal	$	—	$	(122)	$	(123)
State	375		35		42
Total current	$	375	$	(87)	$	(81)

Deferred:
Federal	$	1,205	$	(1,406)	$	217
State	(110)		(89)		34
Total deferred	1,095		(1,495)		251
Net income tax expense (benefit)	$	1,470	$	(1,582)	$	170

The reconciliation of the statutory income tax rate to the Company’s effective income tax rate for the fiscal years ended June 30, 2021, 2020 and 2019 is as follows:


	Year Ended June 30,
	2021		2020		2019
Statutory rate	21.0	%	21.0	%	21.0	%
State income taxes, net	1.4	%	(1.0)	%	22.9	%
Non-deductible expenses	0.2	%	1.6	%	2.7	%
Stock-based compensation	(10.5)	%	0.7	%	16.1	%
Non-deductible compensation	2.7	%	—	%	—	%
PPP loan	(3.2)	%	—	%	—	%
Research and development credits	(1.3)	%	(5.3)	%	7.3	%

Other	—	%	(1.5)	%	1.5	%
Effective rate before valuation allowance	10.3	%	15.5	%	71.5	%
Change in valuation allowance	—	%	(247.1)	%	(27.2)	%
Effective tax rate	10.3	%	(231.6)	%	44.3	%

The Company has historically recorded a valuation allowance to reduce its deferred tax assets to an amount that is more likely than not to be realized. However, as of the year ended June 30, 2020, the Company released the full amount of the valuation allowance against its deferred tax assets on the basis of the Company's reassessment of the recoverability of its deferred tax assets.

At each reporting date, management considers new evidence, both positive and negative, that could affect its view of the future realization of deferred tax assets. As of the years ended June 30, 2021 and June 30, 2020, the Company had a cumulative positive amount of pretax income over a period of three years. The Company expects to utilize all U.S. federal and state net operating loss carryforward balances and all remaining research and development credits.

At June 30, 2021 and 2020, the significant components of deferred tax assets and liabilities are as follows (in thousands):


	June 30,
	2021		2020
Deferred tax assets relating to:
Stock-based compensation	$	85	$	211
Research and development credits	717		490

Inventory	68		98
Professional fees	193		175





Deferred tax assets related to other items	251		140
Net operating loss carryforwards	142		1,016
Total deferred tax assets	1,456		2,130
Deferred tax liabilities related to depreciable and amortizable assets	(1,278)		(836)
Deferred tax liabilities related to other items	(21)		(42)

Net deferred tax asset	$	157	$	1,252

At June 30, 2021, the Company had net operating loss carryforwards of $0.7 million, which will expire, if unused, between June 30, 2037 and June 30, 2038. At June 30, 2021, the Company had various tax credit carryforwards of $0.7 million which will expire beginning on June 30, 2030.

On March 27, 2020, the Coronavirus Aid, Relief, and Economic Security ("CARES") Act was enacted in response to the COVID-19 pandemic. The CARES Act, among other things, accelerated the Company's ability to recover refundable AMT credits to 2018 and 2019. As such, the Company recorded the remaining balance of its AMT credits as a current income tax receivable at June 30, 2020. The Company received $0.3 million and $0.2 million of refundable AMT credits in the years ended June 30, 2021 and 2020, respectively.