| Summary of Significant Accounting Policies - Summary of Customers Whose Revenue and Accounts Receivable Balances (Parenthetical) (Detail) - Customer Concentration Risk [Member] - Revenue [Member] | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
| Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020 | |
| Concentration Risk [Line Items] | ||||
| Concentration risk percentage | 100.00% | 100.00% | 100.00% | 100.00% | 
| Maximum [Member] | ||||
| Concentration Risk [Line Items] | ||||
| Concentration risk percentage | 10.00% | |||
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. No definition available. 
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- Definition For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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