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

Revenue (Details)

v3.21.2
Revenue (Details) - USD ($)
$ in Thousands
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2021
Sep. 30, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Disaggregation of revenue              
Total revenue $ 83,098 $ 61,037 $ 227,208 $ 165,276 $ 243,917 $ 182,663 $ 104,304
Unbilled receivable 36,100   36,100   44,900 25,100  
Revenue concession         4,600    
Advertiser - direct              
Disaggregation of revenue              
Total revenue 34,057 27,582 93,260 73,476 106,422 84,423 60,122
Advertiser - programmatic              
Disaggregation of revenue              
Total revenue 41,902 28,044 113,694 76,023 116,115 83,475 36,866
Supply - side customer              
Disaggregation of revenue              
Total revenue $ 7,139 $ 5,411 $ 20,254 $ 15,777 $ 21,380 $ 14,765 $ 7,316