Quarterly report pursuant to Section 13 or 15(d)

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

v3.8.0.1
Long-Term Debt - Hercules Term Loan - Additional Information (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 21, 2017
Feb. 27, 2015
Mar. 31, 2018
Mar. 31, 2017
Debt Instrument [Line Items]        
Loss on extinguishment of debt       $ 515
Hercules Term Loan [Member]        
Debt Instrument [Line Items]        
Variable rate basis     The Hercules Term Loan had a variable interest rate that was 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%.  
Prepayment charge not required to pay 1.00%      
Loss on extinguishment of debt       $ 500
Aggregate number of unregistered shares of common stock called by warrants (in shares)   9,063    
Exercise price of warrants (in dollars per share)   $ 66.20    
Exercisable period of warrants   5 years    
Warrants expiration period   2020-02    
Minimum [Member] | Hercules Term Loan [Member]        
Debt Instrument [Line Items]        
Percentage bearing variable rate   9.40%    
Prime Rate [Member] | Hercules Term Loan [Member]        
Debt Instrument [Line Items]        
Basis spread, addition   9.40%    
Basis spread, subtraction   7.25%