Annual report pursuant to Section 13 and 15(d)

Long-Term Debt and Other Financings - Servier Loan Agreement - Additional Information (Details)

v3.8.0.1
Long-Term Debt and Other Financings - Servier Loan Agreement - Additional Information (Details)
 1 Months Ended 12 Months Ended
Aug. 25, 2017
USD ($)
€ / $
Jan. 09, 2015
EUR (€)
Tranche
Jan. 31, 2017
EUR (€)
Jan. 31, 2016
EUR (€)
Dec. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
€ / $
Dec. 31, 2015
USD ($)
Dec. 31, 2017
EUR (€)
Jan. 31, 2011
USD ($)
Debt Instrument [Line Items]                  
Accrued interest paid         $ 545,000 $ 2,142,000 $ 1,927,000    
Loss on extinguishment of debt         $ 650,000   429,000    
Servier Loan [Member]                  
Debt Instrument [Line Items]                  
Date of agreement         Dec. 30, 2010        
Maximum borrowing capacity under loan agreement | €               € 15,000,000  
Proceeds from loan         $ 19,500,000        
Date of loan amendment         Jan. 09, 2015        
Number of tranches | Tranche   3              
Principal payment amount | €       € 3,000,000          
Accrued interest paid | €       € 200,000          
Unamortized discount on debt                 $ 8,900,000
Amortization of debt discount         $ 400,000 600,000 700,000    
Carrying value of the loan           12,200,000      
Unrealized foreign exchange gain (losses) related to re-measurement of loan discount           5,000 (200,000)    
Outstanding principal balance           $ 12,600,000      
Euro to US Dollar exchange rates | € / $ 1.1932         1.052      
Unrealized foreign exchange gains (loss) related to re-measurement of loan           $ 500,000 $ 1,900,000    
Payment of debt through cash by NIBR $ 14,300,000                
Loss on extinguishment of debt         $ 100,000        
Servier Loan [Member] | Tranche One [Member]                  
Debt Instrument [Line Items]                  
Maturity date   Jan. 15, 2016              
Principal payment amount | €   € 3,000,000              
Servier Loan [Member] | Tranche Two [Member]                  
Debt Instrument [Line Items]                  
Maturity date   Jan. 15, 2017              
Principal payment amount | €   € 5,000,000              
Servier Loan [Member] | Tranche Two [Member] | Amendment No.3 [Member]                  
Debt Instrument [Line Items]                  
Maturity date     Jul. 15, 2017            
Principal payment amount | €     € 5,000,000            
Servier Loan [Member] | Tranche Three [Member]                  
Debt Instrument [Line Items]                  
Maturity date   Jan. 15, 2018              
Principal payment amount | €   € 7,000,000