v3.26.1
Net Loss Per Share - Schedule of Basic and Diluted Net Loss Per Share (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended 6 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2026
Jun. 30, 2025
Earnings Per Share [Abstract]        
Net loss attributable to System1, Inc. basic (in dollars per share) $ (1.54) $ (2.23) $ (7.34) $ (4.37)
Net loss attributable to System1, Inc. diluted (in dollars per share) $ (1.54) $ (2.23) $ (7.34) $ (4.37)
Numerator:        
Net loss attributable to System1, Inc. $ (12,599) $ (17,463) $ (59,666) $ (33,346)
Denominator:        
Weighted-average common shares outstanding used in computing basic net loss per share (in shares) 8,164 7,820 8,127 7,631
Weighted-average common shares outstanding used in computing diluted net loss per share (in shares) 8,164 7,820 8,127 7,631