Annual report pursuant to Section 13 and 15(d)

Capitalization and Equity Structure - Narrative (Details)

v3.20.4
Capitalization and Equity Structure - Narrative (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
Mar. 24, 2020
Oct. 31, 2020
USD ($)
$ / shares
Jun. 30, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Sep. 16, 2019
days
$ / shares
Sep. 30, 2017
$ / shares
shares
Dec. 31, 2015
$ / shares
shares
Class of Warrant or Right [Line Items]                  
Sale of shares (in dollars per share) | $ / shares             $ 1.00    
Number of Consecutive Business days | days             30    
Common stock, shares authorized (in shares)       141,429,000 141,429,000 141,429,000      
Preferred stock, shares authorized (in shares)       10,000,000 10,000,000 10,000,000      
Common stock, shares issued (in shares)       5,795,000 8,349,000 5,795,000      
Common stock, shares outstanding (in shares)       5,795,000 8,349,000 5,795,000      
Preferred stock, shares issued (in shares)       0 0 0      
Preferred stock, shares outstanding (in shares)       0 0 0      
Number warrants called (in shares)                 141,000
Warrants issued (in shares)         996,000        
Warrant expense | $         $ 329 $ 1,096      
Merger/PPO warrant shares exercised (in shares)         723,000        
Loss on modification of warrants | $         $ 0 $ 257      
Reverse stock split 0.0667                
June 2020 Warrants                  
Class of Warrant or Right [Line Items]                  
Class of warrant or right expiration period         5 years 6 months        
June 2020 Investor Warrants                  
Class of Warrant or Right [Line Items]                  
Exercise price (in dollars per share) | $ / shares     $ 5.18   $ 5.18        
Class of warrant or right expiration period         5 years 6 months        
June 2020 Placement Agent Warrants                  
Class of Warrant or Right [Line Items]                  
Exercise price (in dollars per share) | $ / shares     $ 5.64   $ 5.64        
Class of warrant or right cash fee percentage     7.00%            
Class of warrant or right cash fee | $     $ 552            
Class of warrant or right management fee percentage     1.00%            
Class of warrant or right management fee | $     $ 79            
Percentage of warrants issued to purchase shares of common stock     7.00%            
Warrants issued (in shares)     122,000            
Class of warrant or right expiration period         5 years        
Warrant expense | $     $ 98            
Issuance costs | $     808            
Fair value of warrants | $     309            
December 2019 warrants                  
Class of Warrant or Right [Line Items]                  
Exercise price (in dollars per share) | $ / shares         $ 8.10        
Class of warrant or right expiration period       5 years 6 months 1 day        
Duration of put option           30 days      
Put option pay period           5 days      
December 2019 Placement Agent Warrants                  
Class of Warrant or Right [Line Items]                  
Exercise price (in dollars per share) | $ / shares       $ 8.44   $ 8.44      
Warrants issued (in shares)         0        
Class of warrant or right expiration period         5 years        
Merger/PPO warrant shares exercised (in shares)         0        
December 2019 Placement Agent Warrants | Conversion price                  
Class of Warrant or Right [Line Items]                  
Conversion price (in dollars per share) | $ / shares         $ 8.44 8.44      
May 2019 Warrants                  
Class of Warrant or Right [Line Items]                  
Exercise price (in dollars per share) | $ / shares         $ 3.52        
Warrants issued (in shares)         0        
Class of warrant or right expiration period         5 years        
Shares issued (in dollars per share) | $ / shares         $ 4.51        
Merger/PPO warrant shares exercised (in shares)         246,000        
May 2019 Warrants | Conversion price                  
Class of Warrant or Right [Line Items]                  
Conversion price (in dollars per share) | $ / shares         $ 3.52 $ 5.70      
Information agent warrants                  
Class of Warrant or Right [Line Items]                  
Number warrants called (in shares)               13,000  
Exercise price (in dollars per share) | $ / shares               $ 22.50  
2015 warrants                  
Class of Warrant or Right [Line Items]                  
Merger/PPO warrant shares exercised (in shares)         0 35,000      
Loss on modification of warrants | $           $ 257      
Direct offering                  
Class of Warrant or Right [Line Items]                  
Aggregate proceeds | $     7,890            
Issuance costs | $     1,117            
Direct offering | June 2020 Warrants                  
Class of Warrant or Right [Line Items]                  
Aggregate proceeds | $     2,650            
Issuance costs | $     $ 329            
At-the-market offering                  
Class of Warrant or Right [Line Items]                  
Sale of shares (in dollars per share) | $ / shares   $ 6.75              
Value of shares sold | $   $ 7,500              
Common stock | June 2020 Investor Warrants                  
Class of Warrant or Right [Line Items]                  
Number warrants called (in shares)         477,000        
Common stock | May 2019 Warrants                  
Class of Warrant or Right [Line Items]                  
Number warrants called (in shares)         246,000        
Common stock | Direct offering                  
Class of Warrant or Right [Line Items]                  
Number of shares sold (in shares)     1,748,000            
Number warrants called (in shares)       556,000   556,000      
Aggregate proceeds | $     $ 5,240            
Issuance costs | $     $ 479            
Common stock | Direct offering | June 2020 Investor Warrants                  
Class of Warrant or Right [Line Items]                  
Number warrants called (in shares)     874,000   874,000        
Common stock | Direct offering | May 2019 Warrants                  
Class of Warrant or Right [Line Items]                  
Number warrants called (in shares)     444,000            
Warrants for common stock                  
Class of Warrant or Right [Line Items]                  
Number warrants called (in shares)         6,000        
Warrants for common stock | Minimum                  
Class of Warrant or Right [Line Items]                  
Exercise price (in dollars per share) | $ / shares                 $ 41.25