Income Taxes

6 Months Ended

Jun. 30, 2019

Income Tax Disclosure [Abstract]

Income Taxes

Income Taxes

Tax provisions for interim periods are calculated using an estimate of actual taxable income or loss for the respective period, rather than estimating the Company's annual effective income tax rate, as the Company is currently unable to reliably estimate its income for the full year. For the three and six months ended June 30, 2019, the Company had U.S. taxable loss of approximately $55,700 and $147,300, respectively. For the three and six months ended June 30, 2019, the Company recognized $52 and $122, respectively, of current foreign income tax benefit. For the three and six months ended June 30, 2018, the Company had U.S. taxable loss of approximately $30,200 and $65,300, respectively, and recorded $0 and $113, respectively, of current domestic income tax expense. For the three and six months ended June 30, 2018, the Company recognized $112 and $237, respectively, of current foreign income tax benefit. For the three and six months ended June 30, 2019, the Company recorded deferred tax benefit of $473 and $981, respectively. For the three and six months ended June 30, 2018, the Company recorded deferred tax benefit of $1,015 and $5,089, respectively. The Company's net deferred tax assets, excluding certain deferred tax liabilities totaling $6,332, are offset by a valuation allowance due to the Company's history of net losses combined with an inability to confirm recovery of the tax benefits of the Company's losses and other net deferred tax assets. In assessing the realizability of deferred tax assets, management considers whether it is more likely than not that some portion or all of the deferred tax assets will not be realized. The ultimate realization of deferred tax assets is dependent upon the generation of future taxable income during the periods in which those temporary differences become deductible. Management considers the scheduled reversal of deferred tax liabilities, projected future taxable income and tax planning strategies in making this assessment.

As of June 30, 2019, the Company has operating and capital loss carryforwards for U.S. federal income tax purposes of approximately $516,400 available to offset future taxable income, including approximately $263,900 generated after 2017, and federal and state research and development tax credits of approximately $8,800, prior to consideration of annual limitations that may be imposed under Section 382 of the Internal Revenue Code of 1986, as amended. Carryforwards generated prior to 2018 begin to expire in 2022. As of June 30, 2019, the Company's foreign subsidiaries have foreign loss carryforwards of approximately $162,900, most of which do not expire.