Annual report pursuant to Section 13 and 15(d)

Capital Stock (Details)

v3.3.1.900
Capital Stock (Details) - USD ($)
$ / shares in Units, $ in Thousands
1 Months Ended 11 Months Ended 12 Months Ended 23 Months Ended
Feb. 27, 2015
Dec. 08, 2014
Sep. 27, 2012
Feb. 28, 2015
Dec. 31, 2013
Aug. 31, 2013
Sep. 30, 2012
Mar. 31, 2012
Dec. 31, 2011
Feb. 28, 2010
Jun. 30, 2009
Dec. 31, 2012
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 18, 2013
Aug. 23, 2013
Class Of Warrant Or Right [Line Items]                                    
Offering price (in dollars per share)   $ 4.94                                
Warrant outstanding (in shares)                         18,165,000 21,768,000        
Capital units issued upon the underwriters 30-day over-allotment option (in shares)                                 1,425,000  
Proceeds from issuance of common stock                         $ 481 $ 41,442 $ 84,338      
Reclassification of contingent warrant liability to equity upon exercise of warrants                         $ 3,552 $ 2,526 $ 6,171      
Hercules Loan [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Exercise price of warrants (in dollars per share) $ 3.31                                  
Exercisable period of warrants 5 years                                  
Aggregate number of unregistered shares of common stock called by warrants (in shares) 181,268                                  
Fair value of warrant liability $ 500                                  
General Electric Capital Corporation Term Loan [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Exercise price of warrants (in dollars per share)     $ 3.54           $ 1.14                  
Exercisable period of warrants     5 years           5 years                  
Aggregate number of unregistered shares of common stock called by warrants (in shares)     39,346           263,158                  
Fair value of warrant liability     $ 100           $ 200                  
Five Year Warrants Issued in February 2015 [Member] | Hercules Loan [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Exercise price of warrants (in dollars per share)       $ 3.31                            
Exercisable period of warrants       5 years                            
Aggregate number of unregistered shares of common stock called by warrants (in shares)       181,268                            
Two Year Warrants Issued in December 2014 [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Warrant outstanding (in shares)                         8,097,165 8,097,165        
Exercise price of warrants (in dollars per share)                           $ 7.90        
Warrant term                           2 years        
Fair value of warrant liability   $ 10,300                     $ 3,000 $ 5,200        
Gain (loss) on revaluation of warrant liability                         $ 2,200          
Five Year Warrants Issued in September 2012 [Member] | General Electric Capital Corporation Term Loan [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Exercise price of warrants (in dollars per share)             $ 3.54                      
Exercisable period of warrants             5 years                      
Aggregate number of unregistered shares of common stock called by warrants (in shares)             39,346                      
Five Year Warrants Issued in March 2012 [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Warrant outstanding (in shares)               14,834,577         9,585,153 12,109,418        
Exercise price of warrants (in dollars per share)               $ 1.76                    
Warrant term               5 years                    
Fair value of warrant liability                         $ 7,500 $ 26,700        
Gain (loss) on revaluation of warrant liability                         $ 13,400          
Warrants exercise (in shares)                         2,524,265          
Cashless exercise of warrants (in shares)                         2,523,515          
Exercise of warrants (in shares)                         1,410,474          
Gain (loss) on revaluation of warrant liability related to exercised warrants                         $ 2,200          
Reclassification of contingent warrant liability to equity upon exercise of warrants                         $ 3,600          
Five Year Warrants Issued in December 2011 [Member] | General Electric Capital Corporation Term Loan [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Exercise price of warrants (in dollars per share)                 $ 1.14                  
Exercisable period of warrants                 5 years                  
Aggregate number of unregistered shares of common stock called by warrants (in shares)                 263,158                  
Five Year Warrants Issued in February 2010 [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Warrant outstanding (in shares)                   1,260,000                
Exercise price of warrants (in dollars per share)                   $ 10.50                
Warrant term                   5 years                
Warrants Issued to Private Investors [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Warrant outstanding (in shares)                     347,826              
Exercise price of warrants (in dollars per share)                     $ 19.50              
Warrant term                     5 years              
Underwritten Offering [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Common stock per capital unit (in shares)   1                                
Gross proceeds from issuance of capital units   $ 40,000     $ 57,400 $ 31,600                        
Offering expense   $ 2,300     $ 3,800 $ 2,200                        
Immediate term for warrants exercisable (in years)   2 years                                
Warrant outstanding (in shares)   8,097,165                                
Exercise price of warrants (in dollars per share)   $ 7.90                                
Capital units issued (in shares)                                 10,925,000 8,736,187
Capital units issued upon the underwriters 30-day over-allotment option (in shares)                                   1,139,502
Period to purchase additional stock         30 days 30 days                        
Purchase price of capital units (in dollars per share)                                 $ 5.25 $ 3.62
2011 ATM Agreement [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Sale of shares of common stock (in shares)                       0       7,572,327    
Proceeds from issuance of common stock                       $ 500       $ 14,600    
2015 ATM Agreement [Member]                                    
Class Of Warrant Or Right [Line Items]                                    
Sale of shares of common stock (in shares)                         0          
Sales commission paid per transaction (in hundredths)                         3.00%