INCOME TAXES

The following table summarizes our effective tax rate and income tax expense (benefit) for the three and six months ended June 30, 2017 and 2016 (in thousands except for percentages):



	Three Months Ended June 30,						Six Months Ended June 30,
	2017			2016			2017			2016
Effective tax rate	38		%	199		%	37		%	14		%
Income tax (benefit) expense	$	(8,472	)	$	1,196		$	(29,178	)	$	(1,344	)

For the three and six months ended June 30, 2017, we recognized an income tax benefit of $8.5 million and $29.2 million, respectively, representing an effective tax rate of 38% and 37%, respectively. The difference between the expected statutory federal tax rate of 35% and the effective tax rates for the three and six months ended June 30, 2017, was primarily attributable to the impact of state income taxes and the federal research and development tax credit, partially offset by non-deductible stock compensation.

For the three and six months ended June 30, 2016, we recognized an income tax expense of $1.2 million and an income tax benefit of $1.3 million, respectively, representing an effective tax rate of 199% and 14%, respectively. The difference between the expected statutory federal tax rate of 35% and the 199% effective tax rate for the three months ended June 30, 2016, was primarily attributable to the impact of state income taxes, non-deductible stock compensation, non-deductible contingent consideration expense associated with Lumara Health, and other non-deductible expenses, partially offset by federal research and development and orphan drug tax credits. The effective tax rate for the three months ended June 30, 2016 reflected the significance of these permanent differences in relation to the pre-tax income for the three months ended June 30, 2016. The difference between the expected statutory federal tax rate of 35% and the 14% effective tax rate for the six months ended June 30, 2016, was primarily attributable to the impact of state income taxes and non-deductible stock compensation. The effective tax rates for the three and six months ended June 30, 2016, were also impacted by the impairment of the net intangible asset for the MuGard Rights and related contingent consideration fair value adjustment. We recorded a net tax benefit in the second quarter for these discrete events at a combined federal and state statutory income tax rate of 39%.