Product Revenue and Reserves for Variable Consideration - Summary of Product Revenue Allowance and Reserve Categories (Details) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	$ 31,543	$ 23,737
Current provisions related to sales in current year	74,087	49,610
Adjustments related to prior year sales	651	457
Credits/payments made	(62,177)	(51,114)
Ending balance	44,104	22,690
Chargebacks and Discounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	738	516
Current provisions related to sales in current year	5,055	3,306
Adjustments related to prior year sales	(31)	(22)
Credits/payments made	(4,995)	(3,320)
Ending balance	767	480
Rebates, Fees and other Deductions
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	30,552	22,861
Current provisions related to sales in current year	66,348	44,708
Adjustments related to prior year sales	638	479
Credits/payments made	(54,945)	(46,131)
Ending balance	42,593	21,917
Returns
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Beginning balance	253	360
Current provisions related to sales in current year	2,684	1,596
Adjustments related to prior year sales	44	0
Credits/payments made	(2,237)	(1,663)
Ending balance	$ 744	$ 293

Valuation allowances and reserves adjustments related to prior period sales.

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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- Definition

Amount of valuation and qualifying accounts and reserves.

+ 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(Column B))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

Reference 2: 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(Column E))
-URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e24092-122690

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- Definition

Amount of increase in valuation and qualifying accounts and reserves from charge to cost and expense.

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Amount of decrease in valuation and qualifying accounts and reserves.

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