Entity information:
8.
Income Taxes
 
Def
erred income taxes reflect the net tax effects of temporary differences between the carrying amounts of assets and liabilities for financial reporting purposes and the amounts used for income tax purposes. Significant components of our deferred tax assets (liabilities) as of
December 
31,
2017
and
2016
are as follows (in thousands):
 
   
December
 31
  
   
201
7
    
201
6
  
                 
Net operating loss carryforwards
   $
21,175
     $
32,644
  
Net operating loss carryforwards of foreign subsidiaries
    
374
      
374
  
Book over
tax depreciation
   
(14
)
    
(48
)
Stock-based compensation expense
    
25
      
38
  
Other
    
94
      
124
  
Deferred tax assets
    
21,654
      
33,132
  
Valuation allowance for deferred tax assets
    
(21,654
)
    
(33,132
)
Deferred tax assets, net of allowance
   $
—
     $
—
  
 
Deferred tax assets are required to be reduced by a valuation allowance if it is more likely than
not
that some portion or all of the deferred tax assets will
not
be realized. Realization of the future benefits related to the deferred tax assets is depe
ndent on many factors, including the Company’s ability to generate taxable income within the near to medium term. Management has considered these factors in determining the valuation allowance for
2017
and
2016
.
 
The differences between the provision for
income taxes and income taxes computed using the federal statutory rate for the years ended
December 
31,
2017
and
2016
are as follows (in thousands):
 
   
201
7
    
201
6
  
                 
Reconciliation of income tax benefit to statutory rate:
                
Income benefit at sta
tutory rate
   $
(10
)
   $
(528
)
State income taxes (benefit), net of federal income tax benefit
    
1
      
(40
)
RTP (ISO expense)
    
—
      
38
  
Permanent differences
    
11
      
28
  
Change in valuation allowance
    
(11,478
)
    
890
  
Remeasurment of Deferreds
    
11,476
      
—
  
Change in state tax rate
    
—
      
(345
)
Other
    
—
      
(43
)
    $ —     $ —  
 
At
December
 
31,
2017,
we had federal net operating loss carryforwards of approximately
$87
.9
million for income tax purposes that begin to expire in
2022
and are subject to the ownership change limitations under Internal Revenue Code Section 
382.
We had approximately
$6
million of state net operating loss carryforwards beginning to expire in
2017.