Annual report pursuant to Section 13 and 15(d)

Organization (Details Textual)

v3.8.0.1
Organization (Details Textual)
shares in Thousands, $ in Thousands
 1 Months Ended 12 Months Ended
Aug. 31, 2017
USD ($)
shares
May 31, 2017
Dec. 31, 2017
USD ($)
shares
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Organization [Line Items]            
Retained Earnings (Accumulated Deficit), Total     $ (144,154) $ (114,861)    
Cash and Cash Equivalents, at Carrying Value     27,813 16,846 $ 19,552 $ 25,190
Net Cash Provided by (Used in) Operating Activities     (31,226) (24,997) (18,269)  
Proceeds from Issuance of Common Stock     42,463 $ 14,694 $ 0  
Restructuring and Related Cost, Number of Positions Eliminated   27        
Restructuring Charges     659      
Severance Costs     473      
Employee Benefits and Share-based Compensation     $ (186)      
Registered Direct Offering [Member]            
Organization [Line Items]            
Stock Issued During Period, Shares, New Issues | shares     3,732      
Proceeds from Issuance of Common Stock     $ 10,919      
Rights Offering [Member]            
Organization [Line Items]            
Stock Issued During Period, Shares, New Issues | shares 13,465   13,465      
Proceeds from Issuance of Common Stock $ 13,179   $ 13,179      
Private Placement [Member]            
Organization [Line Items]            
Stock Issued During Period, Shares, New Issues | shares     20,535      
Proceeds from Issuance of Private Placement     $ 20,535