Quarterly report pursuant to Section 13 or 15(d)

STOCKHOLDERS' EQUITY, Common Stock (Details)

v3.21.2
STOCKHOLDERS' EQUITY, Common Stock (Details) - USD ($)
3 Months Ended 9 Months Ended
Sep. 03, 2021
Feb. 03, 2021
Aug. 05, 2020
Feb. 21, 2020
Feb. 11, 2020
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Sep. 30, 2020
Mar. 31, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Common Stock [Abstract]                          
Common stock, shares authorized (in shares)           300,000,000         300,000,000   150,000,000
Common stock, par value (in dollars per share)           $ 0.0001         $ 0.0001   $ 0.0001
Common stock, shares outstanding (in shares)           138,313,817         138,313,817   104,902,888
Warrants outstanding (in shares)           16,828,915         16,828,915    
Common stock, available for issuance (in shares)           144,641,489         144,641,489    
Common stock issuable under agreement           $ 8,213,602 $ 17,189,560 $ 41,912,515 $ 10,639,168 $ 88,704,039      
Net proceeds from issuance of common stock                     $ 67,315,677 $ 99,343,207  
Underwritten Public Offering [Member]                          
Common Stock [Abstract]                          
Net proceeds from issuance of common stock                       $ 88,700,000  
Gross proceeds from issuance of common stock       $ 12,300,000 $ 82,300,000                
Sale Agreement [Member] | Jefferies LLC [Member] | Maximum [Member]                          
Common Stock [Abstract]                          
Common stock issuable under agreement     $ 50,000,000                    
2020 Sale Agreement [Member] | Jefferies LLC [Member]                          
Common Stock [Abstract]                          
Net proceeds from issuance of common stock                     60,400,000    
Sale Agreement, Amended [Member] | Jefferies LLC [Member] | Maximum [Member]                          
Common Stock [Abstract]                          
Common stock issuable under agreement   $ 105,400,000                      
Distribution Agreement [Member] | Raymond James & Associates Inc. [Member]                          
Common Stock [Abstract]                          
Net proceeds from issuance of common stock                     $ 6,900,000    
Distribution Agreement [Member] | Raymond James & Associates Inc. [Member] | Maximum [Member]                          
Common Stock [Abstract]                          
Common stock issuable under agreement $ 50,000,000                        
Common Stock [Member]                          
Common Stock [Abstract]                          
Warrants outstanding (in shares)           4,528,160         4,528,160   4,528,160
Common stock issuable under agreement           $ 644 $ 883 $ 1,808 $ 325 $ 2,703      
Common stock shares sold during the period (in shares)           6,438,276 8,827,045 18,080,708 3,251,195 27,025,000      
Common Stock [Member] | Underwritten Public Offering [Member]                          
Common Stock [Abstract]                          
Common stock shares sold during the period (in shares)       3,525,000 23,500,000                
Common Stock [Member] | 2020 Sale Agreement [Member] | Jefferies LLC [Member]                          
Common Stock [Abstract]                          
Common stock shares sold during the period (in shares)                     27,805,198    
Common Stock [Member] | Distribution Agreement [Member] | Raymond James & Associates Inc. [Member]                          
Common Stock [Abstract]                          
Common stock shares sold during the period (in shares)                     5,540,831