Income Tax Expense

6 Months Ended

Jun. 30, 2017

Current Income Tax Expense (Benefit), Continuing Operations [Abstract]

Income Tax Expense

Income Tax Expense

The Company applied an estimated annual effective tax rate (“ETR”) approach for calculating a tax provision for interim periods. The Company recorded a provision for income taxes of $0.1 million and $0.3 million for the three and six months endedJune 30, 2017, respectively. The Company's ETR was (0.7)% for the three and six months endedJune 30, 2017. The Company's ETR for the three and six months endedJune 30, 2017 differs from the U.S. federal statutory tax rate of 34% primarily as a result of nondeductible expenses (including the Nellix Contingent Payment), state income taxes, foreign income taxes, and the impact of a full valuation allowance on its deferred tax assets.

The Company has evaluated the available evidence supporting the realization of its deferred tax assets, including the amount and timing of future taxable income, and has determined that it is more likely than not that its net deferred tax assets will not be realized in the U.S. and certain foreign jurisdictions. Due to uncertainties surrounding the realization of the deferred tax assets, the Company maintains a full valuation allowance against substantially all deferred tax assets. If/when the Company determines that it will be able to realize some portion or all of its deferred tax assets, an adjustment to its valuation allowance on its deferred tax assets would have the effect of increasing net income in the period(s) such determination is made.