Quarterly report pursuant to Section 13 or 15(d)

Long-Term Debt - Hercules Term Loan - Additional Information (Details)

v3.5.0.2
Long-Term Debt - Hercules Term Loan - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
 1 Months Ended 3 Months Ended 6 Months Ended
Feb. 27, 2015
Feb. 29, 2016
Jun. 30, 2016
Jun. 30, 2015
Jun. 30, 2016
Jun. 30, 2015
Dec. 31, 2015
Debt Instrument [Line Items]              
Aggregate number of unregistered shares of common stock called by warrants (in shares)   165,000          
Exercise price of warrants (in dollars per share)   $ 0.77          
Estimated fair value of warrants   $ 100          
Exercisable period of warrants   5 years          
Warrants expiration period   2021-02          
Carrying value of the loan     $ 46,524   $ 46,524   $ 48,667
Hercules Term Loan [Member]              
Debt Instrument [Line Items]              
Maturity date Sep. 01, 2018            
Variable rate basis         The Hercules Term Loan has a variable interest rate that is the greater of either (i) 9.40% plus the prime rate as reported from time to time in The Wall Street Journal minus 7.25%, or (ii) 9.40%.    
Period of principal and interest amortized 30 months            
Amortization of interest payments period end date Jun. 01, 2016            
Period of interest 1 month            
Prepayment fee within twelve months of maturity 3.00%            
Prepayment fee after twelve months but before twenty four months of maturity 2.00%            
Prepayment fee after twenty four months of maturity 1.00%            
Additional interest rate in case of default 5.00%            
Debt issuance costs $ 500            
Final payment fee $ 1,200            
Amortization of debt discount     200 $ 100 $ 300 $ 200  
Aggregate number of unregistered shares of common stock called by warrants (in shares) 181,268            
Exercise price of warrants (in dollars per share) $ 3.31            
Estimated fair value of warrants $ 500            
Exercisable period of warrants 5 years            
Warrants expiration period 2020-02            
Outstanding principal balance     20,000   20,000   20,000
Carrying value of the loan     $ 20,000   $ 20,000   $ 19,700
Minimum [Member] | Hercules Term Loan [Member]              
Debt Instrument [Line Items]              
Percentage bearing variable rate     9.40%   9.40%    
Prime Rate [Member] | Hercules Term Loan [Member]              
Debt Instrument [Line Items]              
Basis spread, addition         9.40%    
Basis spread, subtraction     7.25%   7.25%