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Revenue Recognition - Summarize Activity of the Net Product Revenue Allowance and Reserve Categories (Detail) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Valuation and Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | $ 65,244 | $ 48,093
Provision related to current period sales | 94,995 | 45,860
Provision related to prior period sales |  | (704)
Credits/payments made for current period sales | (28,009) | (13,161)
Credits/payments made for prior period sales | (47,659) | (24,651)
Ending balance | 84,571 | 55,437
Trade Allowances |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 19,495 | 12,035
Provision related to current period sales | 15,881 | 8,506
Provision related to prior period sales |  | (200)
Credits/payments made for current period sales | (2,624) | (875)
Credits/payments made for prior period sales | (8,760) | (1,336)
Ending balance | 23,992 | 18,130
Rebates, Chargebacks and Discounts |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 41,634 | 32,064
Provision related to current period sales | 70,410 | 32,947
Provision related to prior period sales |  | (435)
Credits/payments made for current period sales | (18,494) | (10,487)
Credits/payments made for prior period sales | (37,521) | (20,994)
Ending balance | 56,029 | 33,095
Product Returns |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 2,948 | 1,887
Provision related to current period sales | 418 | 222
Credits/payments made for prior period sales | (179) | (25)
Ending balance | 3,187 | 2,084
Other Incentives |  |
Valuation and Qualifying Accounts Disclosure [Line Items] |  |
Beginning balance | 1,167 | 2,107
Provision related to current period sales | 8,286 | 4,185
Provision related to prior period sales |  | (69)
Credits/payments made for current period sales | (6,891) | (1,799)
Credits/payments made for prior period sales | (1,199) | (2,296)
Ending balance | $ 1,363 | $ 2,128

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- Definition Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 4 -Subparagraph (SX 210.12-09) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690 + Details
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