Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2016
Income Tax Disclosure [Abstract]  
Components of Income Taxes (Benefit)

The Company’s benefit from income taxes is as follows:

 

     December 31,  
         2016              2015              2014      

Current:

         

Federal

    $ —        $ —        $ —    

State

      (468 )       (397 )       (201 ) 
  

 

 

     

 

 

     

 

 

  
     (468 )       (397 )       (201 ) 
  

 

 

     

 

 

     

 

 

  

Deferred:

         

Federal

      —          —          —    

State

      —          —          —    
  

 

 

     

 

 

     

 

 

  
     —          —          —    
  

 

 

     

 

 

     

 

 

  

Benefit from income taxes

    $ (468 )     $ (397 )     $ (201 ) 
  

 

 

     

 

 

     

 

 
Schedule of Reconciliation of Income Taxes Computed Using U.S. Federal Statutory Rate to that Reflected in Operations

A reconciliation of income taxes computed using the U.S. federal statutory rate to that reflected in operations is as follows:

 

     December 31,  
     2016     2015     2014  

Income taxes using U.S. federal statutory rate

      34.00 %      34.00 %      34.00 % 

State income taxes, net of federal benefit

      5.44 %      5.95 %      5.23 % 

Impact of R&D tax credit on effective tax rate

      3.24 %      3.14 %      3.03 % 

Stock option shortfalls and cancellations

      -0.07 %      -0.03 %      -0.69 % 

Permanent items and other

      -0.64 %      -0.41 %      -0.57 % 

Change in valuation allowance

      -41.17 %      -41.07 %      -39.88 % 
  

 

 

    

 

 

    

 

 

  
     0.81 %      1.58 %      1.12 % 
  

 

 

    

 

 

    

 

 

  

 
Schedule of Significant Components of Company's Deferred Tax Assets

Significant components of the Company’s deferred tax assets are as follows:

 

     December 31,  
     2016     2015  

Net operating loss carryforwards

    $ 57,887     $ 36,217  

Federal and state tax credits

      6,221       4,315  

Accelerated depreciation

      259       1,206  

Stock-based compensation expense

      1,783       1,106  

Other

      641       189  
  

 

 

    

 

 

  
     66,791       43,033  

Valuation allowance

      (66,791 )      (43,033 ) 
  

 

 

    

 

 

  

Net deferred tax asset

    $ —       $ —