Income Taxes (Tables)
 12 Months Ended
Dec. 31, 2015
Income Tax Disclosure [Abstract]  
Significant Components of Company's Deferred Taxes

Significant components of the Company’s deferred taxes at December 31, 2014, and 2013 are as follows:

 

  

 

2015

 

 

2014

 

Net operating loss carryforwards

 

$

35,797

 

 

$

29,442

 

Research and development credit carryforwards

 

 

2,066

 

 

 

1,715

 

Capitalized costs

 

 

3,977

 

 

 

3,503

 

Capitalized research and development costs

 

 

17,715

 

 

 

9,938

 

Other

 

 

903

 

 

 

422

 

Total deferred tax assets

 

 

60,458

 

 

 

45,020

 

Valuation allowance

 

 

(60,458

)

 

 

(45,020

)

Net deferred tax assets

 

$

—

 

 

$

—

 

 
Reconciliation of Income Tax Expense Computed at Statutory Federal Income Tax Rate to Income Taxes

A reconciliation of income tax expense computed at the statutory federal income tax rate to income taxes as reflected in the financial statements is as follows:

 

 

 

Years Ended December 31,

 

 

 

2015

 

 

2014

 

Federal income tax expense at statutory rate

 

 

34.0

%

 

 

34.0

%

State income tax, net of federal benefit

 

 

5.0

%

 

 

4.5

%

Permanent differences

 

 

(0.5

%)

 

 

(3.7

%)

Research and development credit

 

 

0.9

%

 

 

0.8

%

Stock compensation

 

 

(0.7

%)

 

 

(0.9

%)

Expiration of state net operating loss

 

 

0.0

%

 

 

(1.7

%)

Other

 

 

0.4

%

 

 

(0.8

%)

Change in valuation allowance

 

 

(39.1

%)

 

 

(32.2

%)

Effective income tax rate

 

 

0.0

%

 

 

0.0

%