Revenue - (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) pharmacy	Jun. 30, 2019 USD ($)	Jun. 30, 2020 USD ($) pharmacy	Jun. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
CONCENTRATION
Number of specialty pharmacies | pharmacy	2		2
Allowance for doubtful accounts	$ 4,400		$ 4,400		$ 3,900
Change in estimate of uncollectible (percent)			0.50%
Change in revenue recognized due to 0.5% change in uncollectible percentage			$ 100
Increase (decrease) to revenues	20,014	$ 26,151	46,692	$ 47,961
Accounting Standards Update 2014-09 | Difference between Revenue Guidance in Effect before and after Topic 606
CONCENTRATION
Increase (decrease) to revenues	(248)	$ 87	1,095	$ 50
COVID-19 potential impacts
CONCENTRATION
Allowance for doubtful accounts	$ 100		$ 100