v3.26.1
Segments - Schedule of Segment Reporting Information, by Segment (Details) - USD ($)
$ in Thousands
3 Months Ended 6 Months Ended
Jun. 30, 2026
Mar. 31, 2026
Jun. 30, 2025
Mar. 31, 2025
Jun. 30, 2026
Jun. 30, 2025
Segment Reporting [Line Items]            
Stock-based compensation expenses $ 3,554   $ 2,005   $ 6,378 $ 3,973
Direct external program expenses: 22,108   13,124   42,402 23,098
Net loss (27,638) $ (26,237) (17,706) $ (15,169) (53,875) (32,875)
Reportable segment            
Segment Reporting [Line Items]            
Personnel expenses excluding stock-based compensation 6,019   5,685   12,268 11,468
Stock-based compensation expenses 3,554   2,005   6,378 3,973
Other research and development 3,182   4,050   4,380 5,179
General and administrative 3,904   2,938   7,995 5,982
Net loss 29,129   18,682   56,267 34,358
Reportable segment | ALTO-100            
Segment Reporting [Line Items]            
Direct external program expenses: 2,044   1,501   3,808 2,625
Reportable segment | ALTO-300            
Segment Reporting [Line Items]            
Direct external program expenses: 1,754   653   3,261 1,575
Reportable segment | ALTO-101            
Segment Reporting [Line Items]            
Direct external program expenses: 1,874   893   7,230 1,862
Reportable segment | ALTO-203            
Segment Reporting [Line Items]            
Direct external program expenses: 54   599   60 1,336
Reportable segment | ALTO-207            
Segment Reporting [Line Items]            
Direct external program expenses: $ 6,744   $ 358   $ 10,887 $ 358