Product Sales - Schedule of Concentration of Risk, by Risk Factor (Details) - Gross Sales Revenue - Customer concentration risk	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Besse Medical, a subsidiary of AmerisourceBergen Corporation
Concentration Risk [Line Items]
Concentration risk, percentage	56.00%	51.00%	55.00%
McKesson Corporation
Concentration Risk [Line Items]
Concentration risk, percentage	36.00%	29.00%	28.00%
Curascript SD Specialty Distribution, a subsidiary of Express Scripts
Concentration Risk [Line Items]
Concentration risk, percentage		19.00%	16.00%

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
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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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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