v3.7.0.1
Income Taxes
3 Months Ended
Mar. 31, 2017
Income Tax Disclosure [Abstract]  
Income Taxes
Income Taxes
Income tax expense for the three months ended March 31, 2017 and 2016 differs from the amount computed by applying the statutory federal income tax rate to income before income taxes. The sources and tax effects of the differences are as follows:
 
Three Months Ended March 31,
 
2017
 
2016
U.S. federal statutory tax rate
35.0
 %
 
35.0
 %
State income taxes, net of federal tax benefit
1.4

 
2.9

General business credits
(1.0
)
 
(2.6
)
Employee stock-based compensation
(1.0
)
 
0.5

Other
0.5

 
1.0

Effective tax rate
34.9
 %
 
36.8
 %

The effective tax rate for the three months ended March 31, 2017 and 2016 differs from the statutory federal income tax rate of 35% primarily due to state income taxes, net of federal tax benefit, general business credits and non-deductible employee stock-based compensation. The decrease in the effective tax rate for the three months ended March 31, 2017 as compared to the three months ended March 31, 2016 is primarily due to excess tax benefits related to stock compensation recognized as income tax benefit instead of additional paid-in capital in accordance with ASU 2016-09. See Note 2 — Summary of Significant Accounting Policies for additional information about our adoption of ASU 2016-09.
We establish a valuation allowance when we consider it more-likely-than-not that some portion or all of the deferred tax assets will not be realized. As of March 31, 2017 and 2016, we did not have a valuation allowance on any of our deferred tax assets as we believed it was more-likely-than-not that we would realize the benefits of our deferred tax assets.
We are subject to examination by the Internal Revenue Service, or IRS, and various state tax authorities. We remain subject to examination of our federal income tax return for the five-months ended December 31, 2009 and the years ended December 31, 2010, through 2015. We generally remain subject to examination of our various state income tax returns for a period of three to four years from the respective dates the returns were filed.
As of March 31, 2017, we have net operating loss carryforwards of approximately $41.2 million and $32.3 million for federal and state tax purposes, respectively, which will be available to offset future income. If not used, these carryforwards will expire between 2017 and 2035. In addition, we have state business tax credits of approximately $7.7 million that can be carried forward indefinitely and other state business tax credits of approximately $1.1 million that will expire 2026.
As of March 31, 2017 and December 31, 2016, we had a liability of $8.4 million and $7.3 million, respectively, for unrecognized tax benefits related to various federal and state income tax matters excluding interest, penalties and related tax benefits. The reconciliation of the beginning unrecognized tax benefits balance to the ending balance is as follows:
 
Three Months Ended March 31,
 
2017
 
2016
 
(In thousands)
Beginning balance
$
7,314

 
$
7,371

Increases related to positions taken during prior years

 

Increases related to positions taken during the current year
1,038

 
889

Decreases related to positions settled with tax authorities

 

Decreases as a result of a lapse of applicable statute of limitations
$

 
$

Ending balance
$
8,352

 
$
8,260

 
 
 
 
The total amount of unrecognized tax benefits that, if recognized, would affect the effective tax rate
$
8,352

 
$
8,260


As of March 31, 2017 and 2016, we recognized accrued interest and penalties related to unrecognized tax benefits of approximately $1.2 million and $0.9 million, respectively.