Income Taxes

3 Months Ended

Mar. 31, 2020

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

During the three months ended March 31, 2020 and 2019, we did not record an income tax benefit related to our loss before income taxes in the statement of operations and comprehensive loss because a valuation allowance has been required to be established for all deferred tax assets due to our cumulative net loss position.

As of December 31, 2019, our gross federal net operating loss carryforwards of $160.9 million will expire at various dates beginning in 2028. In addition, net operating loss carryforwards for state income tax purposes of $347.1 million that include net operating losses that will begin to expire in 2028. We also have gross research and development credit carryforwards of $2.5 million as of December 31, 2019, which will expire at various dates beginning in 2033.

Utilization of the net operating loss carryforwards may be subject to an annual limitation due to the ownership change limitations provided by Section 382 of the Internal Revenue Code of 1986 and similar state provisions. We have not performed a detailed analysis to determine whether an ownership change has occurred. Such a change of ownership would limit our utilization of the net operating losses and could be triggered by subsequent sales of securities by us or our stockholders.

Realization of the deferred tax assets is dependent upon the generation of future taxable income, if any, the amount and timing of which are uncertain. Based on available objective evidence and cumulative losses, we believe it is more likely than not that the deferred tax assets are not recognizable and will not be recognizable until we have sufficient taxable income. Accordingly, the net deferred tax assets have been fully offset by a valuation allowance.

We had less than $0.1 million of gross unrecognized tax benefits as of March 31, 2020 and December 31, 2019.

We file income tax returns in the applicable jurisdictions. The 2015 to 2018 tax years remain open to examination by the major taxing authorities to which we are subject. We do not expect a significant change to our unrecognized tax benefits over the next 12 months.