Annual report pursuant to Section 13 and 15(d)

Statement of Changes in Stockholder's Equity

v3.20.1
Statement of Changes in Stockholder's Equity - USD ($)
Total
Common Stock [Member]
Additional Paid-in Capital [Member]
Accumulated Deficit [Member]
Beginning balance at Dec. 31, 2017 $ 11,758,730 $ 225 $ 185,659,954 $ (173,901,449)
Beginning balance (in shares) at Dec. 31, 2017   22,584,588    
Stock-based compensation - restricted stock units ("RSUs") 15,359,011   15,359,011  
Stock-based compensation - employee stock purchase plan ("ESPP") 574,927   574,927  
Stock-based compensation - performance share units ("PSUs") 819,816   819,816  
Issuance of shares for RSUs   $ 10 (10)  
Issuance of shares for RSUs (in shares)   963,019    
Issuance of shares for PSUs   $ 3 (3)  
Issuance of shares for PSUs (in shares)   294,969    
Exercise of stock options 1,319,461 $ 4 1,319,457  
Exercise of stock options (in shares)   380,745    
Cashless exercise of warrants (in shares)   19,359    
Shares purchased from contributions to the ESPP 531,797 $ 1 531,796  
Shares purchased from contributions to the ESPP (in shares)   62,168    
Issuance of shares in an at-the-market ("ATM") placement, net of issuance costs 38,846,815 $ 22 38,846,793  
Issuance of shares in an at-the-market ("ATM") placement, net of issuance costs (in shares)   2,221,455    
Net loss (50,840,122)     (50,840,122)
Ending balance at Dec. 31, 2018 18,370,435 $ 265 243,111,741 (224,741,571)
Ending balance (in shares) at Dec. 31, 2018   26,526,303    
Stock-based compensation - restricted stock units ("RSUs") 10,190,211   10,190,211  
Stock-based compensation - employee stock purchase plan ("ESPP") 368,021   368,021  
Stock-based compensation - performance share units ("PSUs") 88,348   88,348  
Issuance of shares for RSUs   $ 11 (11)  
Issuance of shares for RSUs (in shares)   1,110,817    
Shares withheld for payroll tax on RSUs (10,207)   (10,207)  
Shares withheld for payroll tax on RSUs (in shares)   (1,329)    
Shares withheld for payroll tax on PSUs (329,159)   (329,159)  
Shares withheld for payroll tax on PSUs (in shares)   (44,481)    
Shares returned (in shares)   (38,666)    
Exercise of stock options 400,103 $ 1 400,102  
Exercise of stock options (in shares)   80,201    
Shares purchased from contributions to the ESPP 457,362 $ 2 457,360  
Shares purchased from contributions to the ESPP (in shares)   178,003    
Issuance of shares and warrants in a private placement, net of issuance costs 23,319,156 $ 33 23,319,123  
Issuance of shares and warrants in a private placement, net of issuance costs (in shares)   3,333,333    
Issuance of shares in an at-the-market ("ATM") placement, net of issuance costs 4,557,693 $ 21 4,557,672  
Issuance of shares in an at-the-market ("ATM") placement, net of issuance costs (in shares)   2,059,625    
Net loss (38,399,089)     (38,399,089)
Ending balance at Dec. 31, 2019 $ 19,012,874 $ 333 $ 282,153,201 $ (263,140,660)
Ending balance (in shares) at Dec. 31, 2019   33,203,806