v3.26.1
Segment Reporting - Schedule of Segment Expenses, Other Segment Items, and Segment Net Loss (Detail) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Research and development expense $ 46,140 $ 30,914
General and administrative expense 11,168 9,138
Other income, net 157 188
Condensed consolidated net loss (56,737) (39,282)
Operating segment [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Other segment items 8,301 7,642
Other income, net (571) (770)
Condensed consolidated net loss (56,737) (39,282)
Operating segment [Member] | SGT-003 [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Research and development expense 22,942 9,166
Operating segment [Member] | SGT-501 [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Research and development expense 1,407 4,466
Operating segment [Member] | SGT-212 [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Research and development expense 3,316 825
Operating segment [Member] | External Research and Development Other [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Research and development expense, other 2,857 2,770
Operating segment [Member] | Internal Research and Development Expense [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
Research and development expense 9,151 6,843
Operating segment [Member] | External General and Administrative Expense [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
General and administrative expense 5,468 4,877
Operating segment [Member] | Internal General and Administrative Expense [Member]    
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]    
General and administrative expense $ 3,866 $ 3,463