XML 112 R98.htm IDEA: XBRL DOCUMENT v3.20.4
Schedule II - Valuation and Qualifying Accounts (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Accounts receivable allowance      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year $ 56 $ 229 $ 259
Provision (Release) for Bad Debts 191 (79) 142
Net Write-offs (94) (94) (172)
Balance at End of Year 153 56 229
Refund reserve      
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]      
Balance at Beginning of Year 554 396 282
Provision (Release) for Bad Debts 44,171 24,987 21,240
Net Write-offs (43,210) (24,829) (21,126)
Balance at End of Year $ 1,515 $ 554 $ 396