Exhibit 12.1

Statement Regarding the Computation of Ratio of Earnings to Combined Fixed Charges and Preferred Stock Dividends

Our earnings are inadequate to cover fixed charges.  The following table sets forth the dollar amount of the coverage deficiency (in thousands) for the periods presented.

   
For the Year Ended December 31,
 
Statement of Operations Data:
 
2016
   
2015
   
2014
   
2013
   
2012
 
Earnings:
                             
Net loss
 
$
(9,307
)
 
$
(14,385
)
 
$
(18,522
)
 
$
(9,499
)
 
$
(6,227
)
Plus fixed charges
   
81
     
78
     
68
     
61
     
58
 
Total loss to cover fixed charges
   
(9,226
)
   
(14,307
)
   
(18,454
)
   
(9,438
)
   
(6,169
)
                                         
Fixed Charges:
                                       
Interest portion of rental expense (see below)
   
81
     
78
     
68
     
61
     
58
 
                                         
Deficiency of earnings to cover fixed charges
   $
(9,307
)
   $
(14,385
)
   $
(18,522
)
   $
(9,499
)
   $
(6,227
)

The estimate of the interest portion of rental expense is calculated as one-third of the total rental expense for the period.