Annual report pursuant to Section 13 and 15(d)

Subsequent events (Details)

v3.21.1
Subsequent events (Details)
 1 Months Ended 3 Months Ended 8 Months Ended 12 Months Ended
Jan. 22, 2021
USD ($)
$ / shares
shares
Jan. 06, 2021
USD ($)
Mar. 30, 2021
USD ($)
$ / shares
shares
Mar. 31, 2021
shares
Dec. 31, 2020
$ / shares
shares
Dec. 31, 2019
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
$ / shares
Nov. 30, 2020
$ / shares
Sep. 30, 2020
$ / shares
Jul. 20, 2020
$ / shares
Jun. 30, 2020
$ / shares
Jun. 24, 2020
$ / shares
Mar. 17, 2020
$ / shares
Dec. 19, 2019
$ / shares
Nov. 04, 2019
$ / shares
Subsequent Event [Line Items]                                
Proceeds from shares issued             $ 18,053,000 $ 15,826,000                
Common stock, par value (in dollars per share) | $ / shares         $ 0.001 $ 0.001 $ 0.001 $ 0.001                
Warrant term                 72 months       84 months   24 months 24 months
Warrants, exercise price (in dollars per share) | $ / shares                 $ 1.00 $ 0.65 $ 1.05 $ 0.75 $ 1.25 $ 1.62 $ 5.00 $ 5.00
Warrants exercised (in shares) | shares         1,687,690 1,144,999 1,937,690                  
Proceeds from warrant exercises             $ 1,048,000 $ 4,007,000                
Stock options granted (in shares) | shares             1,050,000                  
Forecast                                
Subsequent Event [Line Items]                                
Warrants, exercise price (in dollars per share) | $ / shares     $ 4.25                          
Warrants, reduced exercise price (in dollars per share) | $ / shares     $ 1.25                          
Warrants exercised (in shares) | shares     1,047,609                          
Proceeds from warrant exercises     $ 1,300,000                          
Stock options granted (in shares) | shares       5,479,000                        
Subsequent Event | Private Placement                                
Subsequent Event [Line Items]                                
Sale of stock, consideration $ 4,100,000                              
Sale of stock, price (in dollars per share) | $ / shares $ 1.25                              
Number of shares of stock in each unit (in shares) | shares 1                              
Common stock, par value (in dollars per share) | $ / shares $ 0.001                              
Number of warrants in each unit (in shares) | shares 1                              
Warrant term 6 years                              
Number of shares of common stock issuable per warrant (in shares) | shares 1                              
Gross proceeds received $ 3,100,000                              
Gross proceeds receivable $ 1,000,000.0                              
Warrants, exercise price (in dollars per share) | $ / shares $ 1.45                              
Subsequent Event | Private Placement | Officers and directors                                
Subsequent Event [Line Items]                                
Proceeds from shares issued $ 1,600,000                              
Subsequent Event | Old Plank Trail Community Bank, N.A. | Term Loan                                
Subsequent Event [Line Items]                                
Maximum borrowing capacity   $ 6,000,000.0                            
Subsequent Event | Old Plank Trail Community Bank, N.A. | Line of credit                                
Subsequent Event [Line Items]                                
Maximum borrowing capacity   $ 6,000,000.0                            
Fixed charge coverage ratio   1.25