Registration of securities issued in business combination transactions

FAIR VALUE MEASUREMENTS - Changes in the fair value of warrant liabilitiesl (FY) (Details)

v3.21.4
FAIR VALUE MEASUREMENTS - Changes in the fair value of warrant liabilitiesl (FY) (Details) - USD ($)
3 Months Ended 12 Months Ended
Sep. 30, 2021
Jun. 30, 2021
Mar. 31, 2021
Dec. 31, 2020
Dec. 31, 2020
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Fair value at beginning     $ 13,365,500   $ 0
Initial measurement on August 18, 2020 and over-allotment on August 20, 2020         13,602,000
Change in valuation inputs or other assumptions         (236,500)
Fair value at ending       $ 13,365,500 13,365,500
Transfer from Level 3 to Level 1       13,255,000  
Public Warrants          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Fair value at beginning $ 10,925,000 $ 8,280,000 12,995,000   0
Initial measurement on August 18, 2020 and over-allotment on August 20, 2020         13,225,000
Change in valuation inputs or other assumptions (1,035,000) 2,645,000 (4,715,000)   (230,000)
Fair value at ending 9,890,000 10,925,000 8,280,000 12,995,000 12,995,000
Private Placement Warrants          
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]          
Fair value at beginning 321,750 237,250 370,500   0
Initial measurement on August 18, 2020 and over-allotment on August 20, 2020         377,000
Change in valuation inputs or other assumptions (35,750) 84,500 (133,250)   (6,500)
Fair value at ending $ 286,000 $ 321,750 $ 237,250 $ 370,500 $ 370,500