General form of registration statement for all companies including face-amount certificate companies

Prepaid expenses and other current assets (FY) (Details)

v3.21.1
Prepaid expenses and other current assets (FY) (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2020
Aug. 28, 2020
Mar. 05, 2020
Aug. 28, 2019
Mar. 31, 2021
Dec. 31, 2020
Mar. 31, 2020
Dec. 31, 2020
Dec. 31, 2019
Prepaid Expenses and Other Current Assets [Line Items]                  
Prepaid advertising contract with iHeart $ 1,788       $ 2,500 $ 1,788   $ 1,788 $ 1,776
Other prepaid expenses and other current assets 2,286       1,758 2,286   2,286 865
Total Prepaid expenses and other current assets $ 4,074       4,258 4,074   4,074 2,641
Shares issued to third parties for services (in shares)       1,000,000          
Shares issued to third parties for services       $ 3,400 46   $ 125 1,372 3,477
IHeartMedia                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Committed usage amount of media inventory       $ 1,700          
Prepaid services agreement term   1 year              
Other Counterparty | Access to investment platform                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Prepaid services agreement term 1 year                
Other Noncurrent Assets | IHeartMedia                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Prepaid advertising contract with iHeart $ 1,200       $ 500 $ 1,200   $ 1,200 $ 1,100
Common Stock                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Shares issued to third parties for services (in shares)         30,000   125,000 1,160,000 1,008,500
Shares issued to third parties for services               $ 1 $ 1
Common Stock | IHeartMedia                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Shares issued to third parties for services (in shares)     125,000 1,000,000          
Shares issued to third parties for services     $ 100 $ 3,400          
Common Stock | Other Counterparty | Access to investment platform                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Shares issued to third parties for services (in shares) 500,000         500,000      
Shares issued to third parties for services $ 600         $ 500      
Common Stock | Other Counterparty | Marketing services                  
Prepaid Expenses and Other Current Assets [Line Items]                  
Shares issued to third parties for services (in shares) 500,000         500,000      
Shares issued to third parties for services $ 500         $ 500