Revenue Recognition - Narrative (Details) - USD ($)	3 Months Ended	6 Months Ended	9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Adjustments related to prior period sales. Medicaid rebates	$ (1,438,000)	$ 15,134,000	$ 13,700,000
Adjustments related to prior period sales, contractual adjustments	4,475,000	$ 4,200,000	8,700,000
Deferred revenue	6,300,000		6,300,000	$ 6,400,000
Current portion of deferred revenue	1,128,000		1,128,000		$ 0
Perosphere Pharmaceuticals Inc.
Disaggregation of Revenue [Line Items]
Potential milestone payment receivable, subject to FDA clearance	$ 34,800,000		34,800,000
Milestone payment received			$ 0