v3.26.1
Stockholders' equity (Details)
1 Months Ended 3 Months Ended 12 Months Ended 15 Months Ended
Mar. 30, 2026
USD ($)
$ / shares
shares
Jan. 28, 2026
USD ($)
$ / shares
shares
Dec. 08, 2025
USD ($)
$ / shares
shares
Mar. 11, 2024
USD ($)
$ / shares
shares
Apr. 30, 2025
shares
Mar. 31, 2026
USD ($)
Vote
$ / shares
shares
Mar. 31, 2025
USD ($)
Dec. 31, 2025
USD ($)
$ / shares
shares
Mar. 31, 2026
USD ($)
$ / shares
shares
Nov. 08, 2024
USD ($)
Jan. 26, 2024
USD ($)
Common stock                      
Stock, shares authorized | shares           440,000,000     440,000,000    
Common stock, shares authorized | shares           400,000,000   400,000,000 400,000,000    
Common stock, par value (in dollars per share) | $ / shares           $ 0.001   $ 0.001 $ 0.001    
Preferred stock, shares authorized | shares           40,000,000     40,000,000    
Preferred stock, par value (in dollars per share) | $ / shares           $ 0.001     $ 0.001    
Number of voting rights per common share | Vote           1          
Stock based compensation expense | $                 $ 100,000    
Shelf Registration Statement                      
Proceeds from issuance of common stock | $           $ 35,098,813 $ 59,234        
Common stock issuance costs | $           474,664 3,385        
Private Placement                      
Common stock issuance costs | $           474,664 $ 3,385        
Subscription receivable | $           499,999     $ 499,999    
Warrant exercises | $           $ 0   $ 0      
December 2025 Warrants                      
Private Placement                      
Common stock with an exercise price | $ / shares           $ 1.04     $ 1.04    
January 2026 Warrants                      
Private Placement                      
Common stock with an exercise price | $ / shares           0.765     0.765    
March 2026 Warrants                      
Private Placement                      
Common stock with an exercise price | $ / shares           $ 0.683     $ 0.683    
Common Stock                      
Common stock                      
Conversion of preferred stock into common stock (in shares) | shares         12,516            
Series A Convertible Preferred Stock                      
Common stock                      
Convertible preferred stock, shares outstanding | shares           31,194   31,194 31,194    
Number of shares remained to be converted into common stock | shares           15,596   15,596 15,596    
Conversion of preferred stock into common stock (in shares) | shares         25,033            
Private Placement | Pre-funded Warrants                      
Private Placement                      
Warrants to purchase of shares | shares           41,499,626     41,499,626    
March 2024 Private Placement | Pre-funded Warrants                      
Private Placement                      
Warrant exercises | $               $ 91      
Class of warrant or right, number of warrants exercised | shares               91,206      
March 2024 Private Placement | Purchasers | Securities purchase agreement                      
Shelf Registration Statement                      
Shares issued | shares       1,687,712              
Common stock issuance costs | $       $ 1,300,000              
Private Placement                      
Issuance of common stock (in shares) | shares       1,687,712              
Offering price per share | $ / shares       $ 7.29              
Common stock with an exercise price | $ / shares       $ 0.001              
Proceeds from sale of common stock in a private placement | $       $ 16,000,000              
Common stock issuance costs | $       1,300,000              
Expected gross proceeds from potential future warrants cash exercise | $       $ 18,000,000              
March 2024 Private Placement | Purchasers | Securities purchase agreement | Pre-funded Warrants                      
Private Placement                      
Warrants to purchase of shares | shares       507,076              
March 2024 Private Placement | Purchasers | Securities purchase agreement | Tranche A Warrants (Pre-funded Warrants Exercise Price 7.29 Per Share)                      
Private Placement                      
Warrants to purchase of shares | shares       1,097,394              
Common stock with an exercise price | $ / shares       $ 7.29              
Stock issuance anniversary period       3 years              
Number of days after announcement of Phase 2 dose for ATRN-119       30 days              
Volume weighted average price | $ / shares       $ 14.58              
Number of consecutive trading days       30 days              
March 2024 Private Placement | Purchasers | Securities purchase agreement | Tranche B Warrants (Pre-funded Warrants Exercise Price 9.1125 Per Share)                      
Private Placement                      
Warrants to purchase of shares | shares       1,097,394              
Common stock with an exercise price | $ / shares       $ 9.1125              
Stock issuance anniversary period       5 years              
Number of days after announcement of Phase 2 dose for ATRN-119       30 days              
Volume weighted average price | $ / shares       $ 18.225              
Number of consecutive trading days       30 days              
December 2025 Private Placement | Pre-funded Warrants                      
Private Placement                      
Warrant exercises | $               $ 0      
Class of warrant or right, number of warrants exercised | shares           1,376,405   1,198,700      
December 2025 Private Placement | Purchasers | Securities purchase agreement                      
Shelf Registration Statement                      
Shares issued | shares     26,459                
Common stock issuance costs | $     $ 400,000                
Private Placement                      
Issuance of common stock (in shares) | shares     26,459                
Offering price per share | $ / shares     $ 1.165                
Stock issuance anniversary period     5 years                
Proceeds from sale of common stock in a private placement | $     $ 3,100,000                
Common stock issuance costs | $     $ 400,000                
December 2025 Private Placement | Purchasers | Securities purchase agreement | Pre-funded Warrants                      
Private Placement                      
Offering price per share | $ / shares     $ 1.164                
Warrants to purchase of shares | shares     2,596,564                
Common stock with an exercise price | $ / shares     $ 0.001                
December 2025 Private Placement | Purchasers | Securities purchase agreement | December 2025 Warrants                      
Private Placement                      
Warrants to purchase of shares | shares     2,880,533                
Common stock with an exercise price | $ / shares     $ 1.04                
December 2025 Private Placement | Placement Agent | Securities purchase agreement | December 2025 Warrants                      
Private Placement                      
Warrants to purchase of shares | shares     257,510                
January 2026 Private Placement | Pre-funded Warrants                      
Private Placement                      
Class of warrant or right, number of warrants exercised | shares           523,596          
January 2026 Private Placement | Purchasers | Securities purchase agreement                      
Shelf Registration Statement                      
Shares issued | shares   1,877,677                  
Common stock issuance costs | $   $ 500,000                  
Private Placement                      
Issuance of common stock (in shares) | shares   1,877,677                  
Offering price per share | $ / shares   $ 0.8891                  
Common stock issuance costs | $   $ 500,000                  
Issuance of gross proceeds | $   $ 5,600,000                  
January 2026 Private Placement | Purchasers | Securities purchase agreement | Pre-funded Warrants                      
Private Placement                      
Offering price per share | $ / shares   $ 0.8881                  
Warrants to purchase of shares | shares   4,411,180                  
Common stock with an exercise price | $ / shares   $ 0.001                  
January 2026 Private Placement | Purchasers | Securities purchase agreement | January 2026 Warrants                      
Private Placement                      
Warrants to purchase of shares | shares   6,288,857                  
Common stock with an exercise price | $ / shares   $ 0.765                  
Stock issuance anniversary period   2 years                  
March 2026 Private Placement                      
Private Placement                      
Subscription receivable | $           $ 500,000     $ 500,000    
March 2026 Private Placement | Purchasers | Securities purchase agreement                      
Shelf Registration Statement                      
Common stock issuance costs | $ $ 2,300,000                    
Private Placement                      
Common stock issuance costs | $ 2,300,000                    
Issuance of gross proceeds | $ $ 30,000,000                    
March 2026 Private Placement | Purchasers | Securities purchase agreement | Pre-funded Warrants                      
Private Placement                      
Offering price per share | $ / shares $ 0.807                    
Warrants to purchase of shares | shares 37,174,713                    
Common stock with an exercise price | $ / shares $ 0.001                    
March 2026 Private Placement | Purchasers | Securities purchase agreement | March 2026 Warrants                      
Private Placement                      
Warrants to purchase of shares | shares 37,174,713                    
Common stock with an exercise price | $ / shares $ 0.683                    
2024 Shelf Registration Statement                      
Shelf Registration Statement                      
Maximum amount to be issued under universal shelf registration statement | $                     $ 150,000,000
Maximum amount to be issued under at-the-market offering program | $                     1,000,000
Maximum amount to be issued under at-the-market offering program, supplement | $                   $ 3,000,000 $ 2,000,000
2024 Shelf Registration Statement | HCW                      
Shelf Registration Statement                      
Maximum amount to be issued under at-the-market offering program | $                   $ 3,000,000  
2024 ATM offering                      
Shelf Registration Statement                      
Shares issued | shares               1,337,948      
Proceeds from issuance of common stock | $               $ 1,900,000      
Common stock issuance costs | $               $ 76,000      
Private Placement                      
Issuance of common stock (in shares) | shares               1,337,948      
Common stock issuance costs | $               $ 76,000