Summary of Significant Accounting Policies - Concentrations (Details) - item	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Total net revenue | Customer 1
Concentrations
Concentration risk (as a percentage)	100.00%	34.00%	89.00%	33.00%
Total net revenue | Customer 2
Concentrations
Concentration risk (as a percentage)		29.00%		30.00%
Total net revenue | Customer 3
Concentrations
Concentration risk (as a percentage)		27.00%		28.00%
Total net revenue | Customer risk | One major pharmaceutical distributors
Concentrations
Number of major distributors	1		1
Total net revenue | Customer risk | Three major pharmaceutical distributors
Concentrations
Number of major distributors		3		3
Total net revenue | Customer risk | Three major pharmaceutical distributors | Minimum
Concentrations
Concentration risk (as a percentage)			10.00%
Total accounts receivable | Customer 1
Concentrations
Concentration risk (as a percentage)			99.60%