Summary of Accounting Policies - Summary of Balances of Contract Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Summary Of Accounting Policies [Line Items]
Total contract liabilities	$ 685	$ 843
Less: long-term portion	1	5
Contract liabilities – current	684	838
Extended Service Contracts
Summary Of Accounting Policies [Line Items]
Total contract liabilities	223	271
Subscription Software Licenses
Summary Of Accounting Policies [Line Items]
Total contract liabilities	$ 462	$ 572