Quarterly report pursuant to Section 13 or 15(d)

Revenue (Contract Assets and Liabilities) (Details)

v3.21.2
Revenue (Contract Assets and Liabilities) (Details) - USD ($)
3 Months Ended 6 Months Ended
Jun. 30, 2021
Jun. 30, 2020
Jun. 30, 2021
Jun. 30, 2020
Dec. 31, 2020
Revenue from Contract with Customer [Abstract]          
Contract assets $ 229,000   $ 229,000   $ 467,000
Contract with customer, liability 12,700,000   12,700,000   $ 16,400,000
Deferred revenue, revenue recognized $ 4,600,000 $ 3,900,000 8,300,000 $ 6,600,000  
Contract with customer, performance obligation satisfied in previous period     $ 0 $ 0