Summary of Significant Accounting Policies - Revenue Recognition (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Revenues	$ 99,538,000	$ 75,829,000	$ 189,967,000	$ 133,405,000
Sales return period prior to expiry date			6 months
Sales return period subsequent to expiry date			12 months
Milestone revenue	750,000	1,300,000	$ 750,000	1,300,000
Practical expedient
Revenue, Practical Expedient, Incremental Cost of Obtaining Contract [true/false]			true
License and collaboration agreements
Revenues
Guaranteed minimum amounts	0		$ 0
Royalty revenue agreements
Revenues
Guaranteed minimum amounts	0		0
Product
Revenues
Revenues	97,030,000	73,328,000	186,150,000	129,697,000
Oxtellar XR
Revenues
Revenues	20,556,000	17,339,000	39,121,000	31,699,000
Trokendi XR
Revenues
Revenues	76,474,000	55,989,000	147,029,000	97,998,000
Royalty
Revenues
Revenues	1,758,000	1,179,000	3,067,000	2,328,000
Licensing
Revenues
Revenues	$ 750,000	$ 1,322,000	$ 750,000	$ 1,380,000