No provision or benefit for federal or state income taxes has been recorded, as the Company has incurred a net loss for all of the periods presented, and the Company has provided a full valuation allowance against its deferred tax assets.

At December 31, 2018 and 2017, the Company had federal net operating loss carryforwards of approximately $82,545,000 and $56,536,000, respectively, of which federal carryforwards will expire in varying amounts beginning in 2029. At December 31, 2018 and 2017, the Company had Massachusetts net operating loss carryforwards of approximately $78,152,000 and $53,110,000, respectively. In the first quarter of 2017, the Company adopted ASU 2016-09, which removed the requirement to recognize the deferred tax assets on excess tax benefits in respect of share based payments only when realized. As such, during the year ended December 31, 2017, the Company’s gross deferred tax assets and corresponding valuation allowance each included a one-time increase in respect of an additional federal and state net operating losses of $1,432,000. The adoption of ASU 2016-09 did not have an impact on the Company’s balance sheet, results of operations, cash flows or statement of stockholders’ equity because the Company has a full valuation allowance on its deferred tax assets. Utilization of net operating losses may be subject to substantial annual limitations due to the “change in ownership” provisions of the Internal Revenue Code, and similar state provisions. The annual limitations may result in the expiration of net operating losses before utilization. The Company has not yet conducted a study to determine if any such changes have occurred that could limit the Company’s ability to use the net operating losses and tax credit carryforwards. The Company also had research and development tax credit carryforwards at December 31, 2018 and 2017 of approximately $2,926,000 and $1,283,000, respectively.

Significant components of the Company’s net deferred tax asset are as follows:

The Company has maintained a full valuation allowance against its deferred tax assets in all periods presented. A valuation allowance is required to be recorded when it is not more likely than not that some portion or all of the net deferred tax assets will be realized. Since the Company cannot determine that it is more likely than not that it will generate taxable income, and thereby realize the net deferred tax assets, a full valuation allowance has been provided. The valuation allowance increased by $14,583,207 and $5,088,343 in 2018 and 2017, respectively, due to the increase in deferred tax assets, primarily due to net operating loss carryforwards. The Company has no uncertain tax positions at December 31, 2018 and 2017 that would affect its effective tax rate. Since the Company is in a loss carryforward position, the Company is generally subject to U.S. federal and state income tax examinations by tax authorities for all years for which a loss carryforward is available.

Income tax benefits computed using the federal statutory income tax rate differs from the Company’s effective tax rate primarily due to the following:

The Tax Cut and Jobs Act of 2017

On December 22, 2017, the legislation commonly referred to as the Tax Cut and Jobs Act (the “Tax Act”) was enacted into law. The Tax Act, among other things, contains significant changes to corporate taxation, including reduction of the corporate tax rate from a top marginal rate of 35% to a flat rate of 21%; limitation of the tax deduction for interest expense to 30% of adjusted earnings (except for certain small businesses); limitation of the deduction of net operating losses generated in tax years beginning after December 31, 2017 to 80% of taxable income, indefinite carryforward of net operating losses generated in tax years after 2018 and elimination of net operating loss carrybacks; changes in the treatment of offshore earnings regardless of whether they are repatriated; current inclusion in U.S. federal taxable income of certain earnings of controlled foreign corporations, mandatory capitalization of research and development expenses beginning in 2022; immediate deductions for certain new investments instead of deductions for depreciation expense over time; further deduction limits on executive compensation; and modifying, repealing and creating many other business deductions and credits, including the reduction in the orphan drug credit from 50% to 25% of qualifying expenditures. As of December 31, 2017, we made a reasonable estimate of the effects of the Tax Act on our existing deferred taxes and related disclosures by reducing our net federal and state deferred tax assets by $7,815,832 for the reduction in corporate tax rate. This adjustment to our deferred tax assets was offset against the valuation allowance.

Additionally, the SEC staff has issued SAB 118, which allows to record provisional amounts during a measurement period not to extend beyond one year of the enactment date. On December 22, 2017, Staff Accounting Bulletin No. 118 (“SAB 118”) was issued to address the application of U.S. GAAP in situations when a registrant does not have the necessary information available, prepared, or analyzed (including computations) in reasonable detail to complete the accounting for certain income tax effects of the Act. The Company finalized its estimates during the fourth quarter of 2018.