Customer, Supplier and Product Concentration - Disaggregation of Revenue by Customer (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Concentration Risk [Line Items]
Revenues, net	$ 204,693	$ 165,871
Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	100.00%	100.00%
Big 3 Wholesalers
Concentration Risk [Line Items]
Revenues, net	$ 101,161	$ 97,609
Big 3 Wholesalers | Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	49.40%	58.80%
Amerisource
Concentration Risk [Line Items]
Revenues, net	$ 32,718	$ 30,096
Amerisource | Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	16.00%	18.10%
Cardinal
Concentration Risk [Line Items]
Revenues, net	$ 25,390	$ 29,761
Cardinal | Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	12.40%	17.90%
McKesson
Concentration Risk [Line Items]
Revenues, net	$ 43,053	$ 37,752
McKesson | Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	21.00%	22.80%
All Others
Concentration Risk [Line Items]
Revenues, net	$ 103,532	$ 68,262
All Others | Net Revenue | Customer Concentration Risk
Concentration Risk [Line Items]
Concentration risk percentage	50.60%	41.20%