Basis of Presentation and Summary of Significant Accounting Policies - Revenue by Source (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Disaggregation of Revenue [Line Items]
Total revenue	$ 45,663	$ 33,375	$ 191,863	$ 90,638
Material Sales: Captisol
Disaggregation of Revenue [Line Items]
Total revenue	7,027	7,664	19,030	14,336
License fees, milestones and other
Disaggregation of Revenue [Line Items]
Total revenue	2,509	3,780	84,490	15,930
License Fees
Disaggregation of Revenue [Line Items]
Total revenue	265	738	75,201	4,276
Milestone
Disaggregation of Revenue [Line Items]
Total revenue	1,308	2,059	6,052	7,564
Other
Disaggregation of Revenue [Line Items]
Total revenue	$ 936	$ 983	$ 3,237	$ 4,090