Revenues - Components of Deferred Revenue and Customer Liabilities (Detail) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Schedule of Deferred Revenue and Customer Liabilities [Line Items]
Deferred revenue and customer liabilities	$ 24,270	$ 24,802
Deferred Revenue and Customer Liabilities [Member]
Schedule of Deferred Revenue and Customer Liabilities [Line Items]
Deferred revenue	3,322	2,916
Customer arrangements with termination rights	15,479	15,771
Estimated refund liabilities	$ 5,469	$ 6,115