12. Income Taxes

The following table provides details of income taxes for the periods indicated:

	Three Months Ended October 31,						Nine Months Ended October 31,
	2016			2015			2016			2015
	(in thousands)
Income before income taxes	$	29,802		$	30,496		$	40,610		$	75,896
Provision for income taxes		757			1,035			1,150			4,484
Effective tax rate	2.5		%		3.4	%	2.8		%		5.9	%

The effective tax rate decreased for the three and nine months ended October 31, 2016 compared to the same periods in the prior fiscal year primarily due to tax benefits of $2.2 million and $2.8 million, respectively, from excess stock-based compensation deductions following the Company’s early adoption of ASU 2016-09, Compensation – Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting, in the first quarter of fiscal year 2017.

The Company files federal and state income tax returns in the United States and in various foreign jurisdictions. The tax years 2014 to 2016 remain open to examination by U.S. federal tax authorities. The tax years 2004 to 2016 remain open to examination by U.S. state tax authorities. The tax years 2011 to 2016 remain open to examination by foreign tax authorities.

The Company is subject to ongoing examinations of its tax returns by the Internal Revenue Service and other tax authorities in various jurisdictions. The Company regularly assesses the likelihood of adverse outcomes resulting from these examinations to determine the adequacy of its provision for income taxes. These assessments can require considerable estimates and judgments. As of October 31, 2016, the gross amount of unrecognized tax benefits was approximately $35.9 million. If the estimates of income tax liabilities prove to be less than the ultimate assessment, then a further charge to expense could be required. If events occur and the payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities could result in tax benefits being recognized in the period in which the Company determines the liabilities are no longer necessary. The Company does not anticipate significant changes to its uncertain tax positions during the next twelve months.