Balance Sheet Account Details - Contingent Liabilities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Revenue royalty payable on all Cydex-related revenue (as a percent)		20.00%
Cydex-related revenue amount that triggers royalty payments		$ 15,000,000.0
Additional revenue royalty payable when higher threshold of Cydex-related revenue met (percent)		10.00%
Cydex-related revenue amount that triggers additional royalty payments		$ 35,000,000.0
Contingent Liability [Roll Forward]
Commercial rights at beginning of period	$ 14,000,000	8,100,000
Payments	(4,925,000)	(5,000,000)
Fair Value Adjustment	3,426,000	2,500,000
Additions		8,400,000
Commercial rights at end of period	12,501,000	14,000,000
Cydex
Contingent Liability [Roll Forward]
Commercial rights at beginning of period	1,600,000	6,600,000
Payments	(25,000)	(5,000,000)
Fair Value Adjustment	(1,050,000)	0
Additions		0
Commercial rights at end of period	525,000	1,600,000
Metabasis
Contingent Liability [Roll Forward]
Commercial rights at beginning of period	4,000,000	1,500,000
Payments	(3,900,000)	0
Fair Value Adjustment	5,400,000	2,500,000
Additions		0
Commercial rights at end of period	5,500,000	4,000,000
Crystal
Contingent Liability [Roll Forward]
Commercial rights at beginning of period	8,400,000	0
Payments	(1,000,000)	0
Fair Value Adjustment	(924,000)	0
Additions		8,400,000
Commercial rights at end of period	$ 6,476,000	$ 8,400,000