Summary of Significant Accounting Policies - Concentrations (Details) - item	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Total net revenue
Concentrations
Concentration risk (as a percentage)	100.00%	100.00%
Total net revenue | Customer 1
Concentrations
Concentration risk (as a percentage)	68.00%	20.00%
Total net revenue | Customer 2
Concentrations
Concentration risk (as a percentage)	30.00%
Total net revenue | Customer 3
Concentrations
Concentration risk (as a percentage)		21.00%
Total net revenue | Customer 4
Concentrations
Concentration risk (as a percentage)		21.00%
Total net revenue | Customer 5
Concentrations
Concentration risk (as a percentage)		18.00%
Total net revenue | Other
Concentrations
Concentration risk (as a percentage)	2.00%	20.00%
Total net revenue | Customer risk | One major pharmaceutical distributors
Concentrations
Number of major distributors	2
Total net revenue | Customer risk | Two major pharmaceutical distributors
Concentrations
Number of major distributors		4
Total net revenue | Customer risk | Two major pharmaceutical distributors | Minimum
Concentrations
Concentration risk (as a percentage)	10.00%
Total accounts receivable | Customer 1
Concentrations
Concentration risk (as a percentage)	75.00%
Total accounts receivable | Customer 2
Concentrations
Concentration risk (as a percentage)	24.00%	95.00%
Total accounts receivable | Customer 3
Concentrations
Concentration risk (as a percentage)	1.00%	5.00%