Revenue - Revenue by Significant Customer (Details) - Net Product Revenue - Customer Concentration Risk	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Concentration Risk [Line Items]
Percentage of total revenue	100.00%	100.00%	100.00%	100.00%
McKesson
Concentration Risk [Line Items]
Percentage of total revenue	37.00%	42.00%	39.00%	43.00%
AmeriSource-Bergen Corp
Concentration Risk [Line Items]
Percentage of total revenue	38.00%	31.00%	37.00%	32.00%
Cardinal
Concentration Risk [Line Items]
Percentage of total revenue	23.00%	25.00%	22.00%	23.00%
Others
Concentration Risk [Line Items]
Percentage of total revenue	2.00%	2.00%	2.00%	2.00%

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://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592

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