Revenue from Contracts with Customers - Disaggregation of Revenue (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Disaggregation of Revenue [Line Items]
Revenues	$ 85,573,000	$ 88,837,000	$ 168,203,000	$ 170,196,000
Product revenue, net
Disaggregation of Revenue [Line Items]
Revenues	85,004,000		167,072,000
License and royalty revenues
Disaggregation of Revenue [Line Items]
Revenues	569,000		1,131,000
U.S.
Disaggregation of Revenue [Line Items]
Revenues	74,086,000	78,100,000	145,574,000	149,127,000
U.S. | Product revenue, net
Disaggregation of Revenue [Line Items]
Revenues	74,086,000		145,574,000
U.S. | License and royalty revenues
Disaggregation of Revenue [Line Items]
Revenues	0		0
International
Disaggregation of Revenue [Line Items]
Revenues	11,487,000	$ 10,737,000	22,629,000	$ 21,069,000
International | Product revenue, net
Disaggregation of Revenue [Line Items]
Revenues	10,918,000		21,498,000
International | License and royalty revenues
Disaggregation of Revenue [Line Items]
Revenues	$ 569,000		$ 1,131,000