Quarterly report pursuant to Section 13 or 15(d)

STOCKHOLDERS' EQUITY AND LOSS PER SHARE (Details)

v3.21.2
STOCKHOLDERS' EQUITY AND LOSS PER SHARE (Details)
$ / shares in Units, $ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2021
USD ($)
$ / shares
shares
Feb. 11, 2020
USD ($)
shares
Feb. 10, 2020
shares
Feb. 06, 2020
$ / shares
shares
Sep. 30, 2021
USD ($)
vote
$ / shares
shares
Sep. 30, 2020
USD ($)
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
May 31, 2021
USD ($)
Aug. 14, 2020
USD ($)
Class of Stock [Line Items]                  
Common stock, shares authorized (in shares) 100,000,000       100,000,000   100,000,000    
Number of votes | vote         1        
Number of shares issued (in shares)   201,000              
Common stock, par value (in dollars per share) | $ / shares $ 0.001       $ 0.001   $ 0.001    
Consideration received from sale of stock | $   $ 28,800              
Gross proceeds from sale of common stock | $   $ 26,400     $ 12,303 $ 28,750      
Preferred stock, shares authorized (in shares) 3,000,000       3,000,000   3,000,000    
Preferred stock, shares issued (in shares) 0       0        
Loss Per Share                  
Total shares excluded from net loss per share attributable to common stockholders (in shares)         5,414,350 4,704,695      
Common stock options                  
Loss Per Share                  
Total shares excluded from net loss per share attributable to common stockholders (in shares)         958,356 1,152,552      
Non-vested restricted stock unit awards                  
Loss Per Share                  
Total shares excluded from net loss per share attributable to common stockholders (in shares)         4,455,994 3,552,143      
Principal Owner                  
Class of Stock [Line Items]                  
Number of shares issued (in shares)   134,000              
Underwritten Public Offering                  
Class of Stock [Line Items]                  
Number of shares issued (in shares)   19,166,667   16,666,667          
Common stock, par value (in dollars per share) | $ / shares       $ 0.001          
Share price (in dollars per share) | $ / shares       $ 1.50          
Over-Allotment Option                  
Class of Stock [Line Items]                  
Number of shares issued (in shares)   2,500,000              
Over-Allotment Option | Common stock options                  
Class of Stock [Line Items]                  
Number of shares issued (in shares)     2,500,000            
Option to purchase period     30 days            
At-The-Market Equity Offering                  
Class of Stock [Line Items]                  
Number of shares issued (in shares)         3,068,370   4,609,701    
Share price (in dollars per share) | $ / shares $ 4.01       $ 4.01   $ 2.48    
Consideration received from sale of stock | $         $ 12,300   $ 11,400    
Gross proceeds from sale of common stock | $         11,900   $ 11,000    
Remaining authorized amount to be sold | $ $ 1,300       $ 1,300       $ 25,000
Sale of stock, authorized amount | $               $ 50,000  
Universal Shelf Registration                  
Class of Stock [Line Items]                  
Number of shares issued (in shares) 0                
Sale of stock, authorized amount | $               $ 100,000