Revenue From Contracts With Customers - Summary of Information about Receivables and Contract Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Contract Balances [Line Items]
Accounts receivable, current	$ 2,429	$ 3,384
Notes receivable, current	451	502
Notes receivable, long-term	538	827
Contract liability, current	836	777
Notes and Other Receivables, Long-Term, Net
Schedule Of Contract Balances [Line Items]
Notes receivable, long-term	538	827
Deferred Revenue
Schedule Of Contract Balances [Line Items]
Contract liability, current	836	777
Other Long-Term Liabilities
Schedule Of Contract Balances [Line Items]
Contract liability, non-current	$ 47	$ 118