Annual report pursuant to Section 13 and 15(d)

Stockholders' equity - Narrative (Details)

v3.22.0.1
Stockholders' equity - Narrative (Details)
$ / shares in Units, $ in Thousands
 1 Months Ended 12 Months Ended
May 20, 2021
performance_obligation
$ / shares
shares
Apr. 01, 2020
shares
Jan. 30, 2019
shares
Aug. 31, 2021
USD ($)
$ / shares
Nov. 30, 2019
USD ($)
$ / shares
shares
Aug. 31, 2019
USD ($)
Jun. 30, 2016
USD ($)
shares
Dec. 31, 2021
USD ($)
vote
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Jun. 30, 2017
$ / shares
Class of Stock [Line Items]                    
Common stock, shares authorized (shares)               300,000,000 300,000,000  
Common stock, shares outstanding (shares)               72,222,661 56,002,815  
Common stock, shares issued (shares)               72,222,661 56,002,815  
Common Stock, Par or Stated Value Per Share | $ / shares               $ 0.001 $ 0.001  
Preferred stock, shares authorized (shares)               10,000,000 10,000,000  
Preferred stock, shares outstanding (shares)               15,617 14,429  
Preferred stock, shares issued (shares)               15,617 14,429  
Preferred stock, par value (USD per share) | $ / shares               $ 0.001 $ 0.001  
Number of classes of preferred stock | performance_obligation 5                  
Gross proceeds from private placement units sold | $               $ 18,913 $ 0  
Gross sales proceeds from common stock | $           $ 50,000   $ 38,188 $ 9,624  
Jefferies LLC                    
Class of Stock [Line Items]                    
Common Stock, Par or Stated Value Per Share | $ / shares       $ 0.001            
At the market offering                    
Class of Stock [Line Items]                    
Shares of common stock issued (shares)               8,200,000 3,600,000  
Issue price per share (USD per share) | $ / shares                 $ 2.80  
At the market offering | Jefferies LLC                    
Class of Stock [Line Items]                    
Net proceeds from underwritten public offering | $                 $ 10,000  
Sale of stock, authorized amount | $       $ 50,000            
Securities Purchase Agreement                    
Class of Stock [Line Items]                    
Number of capital units sold in private placement transaction (in shares)             8,188,804      
Gross proceeds from private placement units sold | $             $ 16,500      
Net proceeds from private placement units sold | $             $ 15,300      
Two Thousand And Sixteen Private Investment In Public Equity                    
Class of Stock [Line Items]                    
Shares of common stock issued (shares)             3,225,804      
At The Market Offering 1 | Jefferies LLC                    
Class of Stock [Line Items]                    
Issue price per share (USD per share) | $ / shares               $ 4.85    
Net proceeds from underwritten public offering | $               $ 39,700    
Common shares                    
Class of Stock [Line Items]                    
Number of votes per share | vote               1    
Number of shares per unit (shares)               3,812,000    
Common shares | Stock Exchange, Shares from Existing Shareholders                    
Class of Stock [Line Items]                    
Shares of common stock issued (shares) 5,000,000 3,000,000 5,000,000              
Convertible  preferred shares                    
Class of Stock [Line Items]                    
Number of shares per unit (shares)               (4,000)    
Convertible  preferred shares | Preferred Share Exchange                    
Class of Stock [Line Items]                    
Shares of common stock issued (shares)   3,000 5,000              
Series A Convertible Preferred Stock                    
Class of Stock [Line Items]                    
Preferred stock, shares outstanding (shares)               85 2,907  
Preferred stock, shares issued (shares)               85 2,907  
Price per unit issued (USD per share) | $ / shares                   $ 2.015
Series A Convertible Preferred Stock | Private Placement | Two Thousand And Sixteen Private Investment In Public Equity                    
Class of Stock [Line Items]                    
Preferred stock, shares issued (shares)             4,963      
Series B Convertible Preferred Stock                    
Class of Stock [Line Items]                    
Preferred stock, shares outstanding (shares)               4,026 5,000  
Preferred stock, shares issued (shares)               4,026 5,000  
Series C Convertible Preferred Stock                    
Class of Stock [Line Items]                    
Preferred stock, shares outstanding (shares)               3,506 3,522  
Preferred stock, shares issued (shares)               3,506 3,522  
Series C Convertible Preferred Stock | Preferred Share Exchange                    
Class of Stock [Line Items]                    
Issue price per share (USD per share) | $ / shares         $ 3.43          
Beneficial conversion feature | $         $ 2,800          
Series C Convertible Preferred Stock | Private Placement                    
Class of Stock [Line Items]                    
Shares issued upon conversion of convertible preferred stock (shares)         0.001          
Effective period of change to beneficial ownership limitation         60 days          
Shares of common stock issued (shares)         9,014,960          
Number of shares per unit (shares)         1          
Number of shares called by each warrant (in shares)         1          
Exercise price (USD per share) | $ / shares         $ 7.10          
Issue price per share (USD per share) | $ / shares         $ 3.55          
Shares of stock sold, gross consideration | $         $ 32,000          
Net proceeds from underwritten public offering | $         $ 31,000          
Number of warrants included with each unit (in shares)         1          
Period of determining volume weighted average stock price         10 days          
Weighted average stock price commencing on trading day         3.00%          
Series C Convertible Preferred Stock | Private Placement | Maximum                    
Class of Stock [Line Items]                    
Warrants and rights outstanding, term         5 years          
Series D Convertible Preferred Stock                    
Class of Stock [Line Items]                    
Preferred stock, shares outstanding (shares)               3,000 3,000  
Preferred stock, shares issued (shares)               3,000 3,000  
Series E Convertible Preferred Stock                    
Class of Stock [Line Items]                    
Preferred stock, shares outstanding (shares)               5,000 0  
Preferred stock, shares issued (shares)               5,000 0  
Series E Convertible Preferred Stock | Convertible  preferred shares | Preferred Share Exchange                    
Class of Stock [Line Items]                    
Shares of common stock issued (shares) 5,000                  
Series A through Series E | Convertible  preferred shares                    
Class of Stock [Line Items]                    
Preferred stock, par value (USD per share) | $ / shares $ 0.001                  
Shares issued upon conversion of convertible preferred stock (shares) 1,000                  
Common stock ownership limit (as a percent) 9.99%                  
Beneficial ownership limitation (as a percent) 19.99%                  
Effective period of change to beneficial ownership limitation 61 days