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Revenue Recognition - Summarize Activity of the Net Product Revenue Allowance and Reserve Categories (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | $ 128,557 | $ 65,244
Provision related to current period sales | 822,813 | 545,842
Provision related to prior period sales | (3,872) | (324)
Credits/payments made for current period sales | (637,999) | (419,489)
Credits/payments made for prior period sales | (118,675) | (62,716)
Ending balance | 190,824 | 128,557
Trade Allowances |  |
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 29,261 | 19,495
Provision related to current period sales | 132,881 | 92,378
Credits/payments made for current period sales | (96,834) | (63,288)
Credits/payments made for prior period sales | (29,066) | (19,324)
Ending balance | 36,242 | 29,261
Rebates, Chargebacks and Discounts |  |
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 90,997 | 41,634
Provision related to current period sales | 621,937 | 403,865
Provision related to prior period sales | (3,872) | (324)
Credits/payments made for current period sales | (482,254) | (312,790)
Credits/payments made for prior period sales | (85,608) | (41,388)
Ending balance | 141,200 | 90,997
Product Returns |  |
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 4,579 | 2,948
Provision related to current period sales | 3,543 | 2,430
Credits/payments made for current period sales |  | 5
Credits/payments made for prior period sales | (324) | (804)
Ending balance | 7,798 | 4,579
Other Incentives |  |
Valuation And Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 3,720 | 1,167
Provision related to current period sales | 64,452 | 47,169
Credits/payments made for current period sales | (58,911) | (43,416)
Credits/payments made for prior period sales | (3,677) | (1,200)
Ending balance | $ 5,584 | $ 3,720

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