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
Mar. 31, 2026
Mar. 31, 2025
Earnings Per Share [Abstract]    
Net loss attributable to System1, Inc. basic (in dollars per share) $ (5.82) $ (2.14)
Net loss attributable to System1, Inc. diluted (in dollars per share) $ (5.82) $ (2.14)
Numerator:    
Net loss attributable to System1, Inc. $ (47,067) $ (15,883)
Denominator:    
Weighted-average common shares outstanding used in computing basic net loss per share (in shares) 8,090 7,439
Weighted-average common shares outstanding used in computing diluted net loss per share (in shares) 8,090 7,439