Annual report pursuant to Section 13 and 15(d)

Revenue (Detail)

v3.21.1
Revenue (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Deferred revenue $ 1,013 $ 1,217
Remaining performance obligation $ 1,000  
Four Customers | Customer Concentration | Revenue    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Concentration risk percentage 61.00%  
Three Customers | Customer Concentration | Revenue    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Concentration risk percentage   61.00%
Non-US | Geographic Concentration | Revenue    
Accounts, Notes, Loans and Financing Receivable [Line Items]    
Concentration risk percentage 39.00% 20.00%