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Significant Accounting Policies - Summary of Impact of Accounts Receivable Reserves on Gross Trade Accounts Receivable Balances (Detail) - USD ($) $ in Thousands | Sep. 30, 2020 | Dec. 31, 2019
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Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Gross trade accounts receivable | $ 223,579 | $ 149,567
Accounts receivable, net | 147,292 | 116,430
Trade Allowances |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Valuation allowances and reserves | (63,069) | (29,261)
Chargebacks |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Valuation allowances and reserves | (12,273) | $ (3,876)
Allowance for Doubtful Accounts |  |
Accounts, Notes, Loans and Financing Receivable [Line Items] |  |
Valuation allowances and reserves | $ (945) |

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