There was no provision for income taxes for the years ended December 31, 2018 and 2017, due to the Company’s operating losses and a full valuation allowance on deferred tax assets. 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 the Company’s deferred tax assets and liabilities are as follows:

	December 31,
	2018			2017
Deferred tax assets:
Net operating loss carry forwards	$	3,604,179		$	1,843,000
Capitalized research and development costs		14,381,936			12,177,000
Accrued liabilities		232,899			25,000
Tax credit carryforwards		6,311,164			3,286,000
Stock-based compensation		394,918			116,000
Total deferred tax assets		24,925,096			17,447,000

Valuation allowance		(24,922,829	)		(17,444,000	)
Net deferred tax assets		2,267			3,000

Deferred tax liabilities		(2,267	)		(3,000	)
	$	—		$	—

A reconciliation of the United States federal statutory tax rate to the effective tax rate is as follows:

	December 31,
	2018			2017
Federal statutory rate		21.0	%		34.0	%
R&D and Orphan Drug credits		10.9	%		7.6	%
State income tax, net of federal tax benefit		2.8	%		(0.2	%)
Valuation allowance		(35.2	%)		18.2	%
Tax reform impact		0.0	%		(57.8	%)
Other, net		0.5	%		(1.8	%)
Effective tax rate		0.0	%		0.0	%

Management currently believes that it is more likely than not that the deferred tax assets relating to the loss carryforwards and other temporary differences will not be realized in the future. Through December 31, 2018, for income tax reporting purposes, the Company had United States federal and state net operating loss carryforwards of approximately $15.9 million and research and development credits and Orphan Drug credits of approximately $6.3 million that can be carried forward and offset against taxable income. Federal net operating loss generated prior to 2018, research and development credits and Orphan Drug credits, and Massachusetts net operating losses can be carried forward for 20 years and begin to expire in 2022. Federal net operating loss generated in 2018 can be carried forward indefinitely. Utilization of net operating losses may be subject to substantial annual limitations due to the “change in ownership” provisions of the Internal Revenue Code of 1986, and similar state provisions. The annual limitations may result in the expiration of net operating losses before utilization.

On December 22, 2017, The Tax Cuts and Jobs Act (the “Act”) was enacted. The Act significantly revised the United States corporate income tax law by lowering the corporate federal income tax rate from 35% to 21%. As of December 31, 2017, the Company has assessed the effects of the corporate rate reduction on its existing deferred tax balances which resulted in a $8.2 million reduction in the deferred tax assets. Since the Company maintains a full valuation allowance on its deferred tax assets, a corresponding reduction in the valuation allowance equal to the effect of the rate reduction on the ending deferred tax asset was also reflected. In addition to the rate reduction, the Act also requires companies with foreign subsidiaries to pay a one-time transition tax on earnings that were previously tax deferred. As of December 31, 2017, the Company does not maintain any foreign subsidiaries and does not have previously deferred foreign earnings subject to the transition tax.