Income Taxes	3 Months Ended
Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	10. Income Taxes Income tax expense during interim periods is based on applying an estimated annual effective income tax rate to year-to-date income, plus any significant unusual or infrequently occurring items that are recorded in the interim period. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in various jurisdictions, permanent and temporary differences, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, more experience is obtained, additional information becomes known, or as the tax environment changes. The interim financial statement provision for income taxes expense is different from the amounts computed by applying the United States federal statutory income tax rate of 21%. The Company’s effective tax rate was -0.1% and -0.2% for the three months ended March 31, 2019 and 2018, respectively. The difference between the effective tax rate and the federal statutory rate of 21% was primarily due to the full valuation allowance recorded on the Company’s net deferred tax assets and foreign withholding taxes. The Company may have experienced an ownership change under IRC Section 382 as a result of the common shares issued in connection with the March 2018 Purchase Agreement or in the June 2018 Offering. Such an ownership change may limit the Company’s ability to utilize its net operating loss carryforwards prior to expiration. Given the full valuation allowance, such a limitation would not impact the deferred tax asset balance as currently recorded. As of March 31, 2019, there have been no material changes to the Company’s uncertain tax positions.

Income Taxes

3 Months Ended

Mar. 31, 2019

10. Income Taxes

Income tax expense during interim periods is based on applying an estimated annual effective income tax rate to year-to-date income, plus any significant unusual or infrequently occurring items that are recorded in the interim period. The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgment including, but not limited to, the expected operating income for the year, projections of the proportion of income earned and taxed in various jurisdictions, permanent and temporary differences, and the likelihood of recovering deferred tax assets generated in the current year. The accounting estimates used to compute the provision for income taxes may change as new events occur, more experience is obtained, additional information becomes known, or as the tax environment changes.

The interim financial statement provision for income taxes expense is different from the amounts computed by applying the United States federal statutory income tax rate of 21%. The Company’s effective tax rate was -0.1% and -0.2% for the three months ended March 31, 2019 and 2018, respectively. The difference between the effective tax rate and the federal statutory rate of 21% was primarily due to the full valuation allowance recorded on the Company’s net deferred tax assets and foreign withholding taxes.

The Company may have experienced an ownership change under IRC Section 382 as a result of the common shares issued in connection with the March 2018 Purchase Agreement or in the June 2018 Offering. Such an ownership change may limit the Company’s ability to utilize its net operating loss carryforwards prior to expiration. Given the full valuation allowance, such a limitation would not impact the deferred tax asset balance as currently recorded.

As of March 31, 2019, there have been no material changes to the Company’s uncertain tax positions.