v3.24.4
Stock-based Compensation - Schedule of Options Activity (Q3) (Details) - USD ($)
$ / shares in Units, $ in Thousands
 9 Months Ended 12 Months Ended
Sep. 30, 2024
Dec. 31, 2023
Total Options    
Beginning balance (in shares) 23,912 51,166
Forfeitures (in shares) (4,502) (17,173)
Ending balance (in shares) 19,410 23,912
Total options exercisable (in shares) 17,478 18,705
Weighted- Average Exercise Price Per Share    
Options outstanding, weighted-average exercise price per share, beginning balance (in dollars per share) $ 68.39 $ 60.69
Forfeitures (in dollars per share) 11.96 77.95
Options outstanding, weighted-average exercise price per share, ending balance (in dollars per share) 81.48 68.39
Options exercisable, weighted-average exercise price per share (in dollars per share) $ 76.44 $ 54.36
Stock Options Additional Disclosures    
Options outstanding, weighted-average remaining contractual term (in years) 6 years 7 months 6 days 7 years 1 month 6 days
Options exercisable, weighted-average remaining contractual term (in years) 6 years 6 months 6 years 9 months 18 days
Options outstanding, aggregate intrinsic value $ 0 $ 0
Options exercisable, aggregate intrinsic value $ 0 $ 0
Vested and Expected to Vest    
Total options vested and expected to vest (in shares) 19,410 23,912
Options vested and expected to vest, weighted-average exercise price per share (in dollars per share) $ 81.48 $ 68.39
Options vested and expected to vest, weighted-average remaining contractual term (in years) 6 years 7 months 6 days 7 years 1 month 6 days
Options vested and expected to vest, aggregate intrinsic value $ 0 $ 0