Income Taxes (Tables)
12 Months Ended
Dec. 31, 2015
Income Tax Disclosure [Abstract]  
Components of Federal and State Income Tax Expense

before income taxes was generated in the United States. The components of federal and state income tax expense are as follows (in thousands):

 

     Year Ended
December 31,
 
     2015      2014  

Current

     

Federal

   $ —        $ —    

State

     —          —    
  

 

 

    

 

 

 

Total current

     —          —    

Deferred

     

Federal

     (3,157      (2,727

State

     (803      (583
  

 

 

    

 

 

 

Total deferred

     (3,960      (3,310

Valuation allowance

     3,960         3,310   
  

 

 

    

 

 

 

Total income tax expense

   $ —        $ —    
  

 

 

    

 

 

 
Effect Income Tax Rate Reconciliation

The differences between the income taxes expected at the Federal statutory income tax rate and the reported income tax (benefit) expense is as follows:

 

     2015     2014  

Federal statutory rate

     34.0     34.0

State income taxes, net of federal benefit

     4.8        4.2   

Non-deductible expenses

     (1.9     (2.1

Income tax credits

     1.9        1.6   

Valuation allowance

     (38.8     (37.7
  

 

 

   

 

 

 

Effective tax rate

     0.0     0.0
  

 

 

   

 

 

 
Components of Net Deferred Tax Assets

as a result of this change. The components of net deferred tax assets are as follows (in thousands):

 

     As of December 31,  
     2015      2014  

Net operating loss carryforwards

   $ 13,552       $ 9,805   

Tax credit carryforwards

     442         261   

Stock-based compensation

     1,744         1,392   

Licensing deduction deferral

     5,979         6,367   

Other timing differences

     178         110   
  

 

 

    

 

 

 

Gross deferred tax assets

     21,895         17,935   

Valuation allowance

     (21,895      (17,935
  

 

 

    

 

 

 

Net deferred tax asset

   $ —        $ —