Revenue From Contracts With Customers - Summary of Information about Receivables and Contract Liabilities from Contracts with Customers (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Schedule Of Contract Balances [Line Items]
Accounts receivable, current	$ 2,105	$ 2,012
Notes receivable, current	427	444
Notes receivable, long-term	364	452
Contract liability, current	967	923
Notes and Other Receivables, Long-Term, Net
Schedule Of Contract Balances [Line Items]
Notes receivable, long-term	364	452
Deferred Revenue
Schedule Of Contract Balances [Line Items]
Contract liability, current	967	923
Other Long-Term Liabilities
Schedule Of Contract Balances [Line Items]
Contract liability, non-current	$ 97	$ 128