Discontinued Operations - Schedule of Discontinued Operations (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Other income and expenses:
Total income from discontinued operations	$ 0	$ 540,485,000	$ 0	$ 539,538,000
Commercial Business [Member]
Revenues:
Product revenues, net				16,135,000
License and collaboration revenues				7,797,000
Other revenues				1,973,000
Total revenues				25,905,000
Costs and expenses:
Cost of revenues				3,890,000
Research and development expenses				3,700,000
Selling, general and administrative expenses				8,709,000
Restructuring expenses		4,216,000		9,535,000
Total costs and expenses		4,216,000		25,834,000
Other income and expenses:
Interest expense		(1,509,000)		(6,743,000)
Gain on sale of commercial business		598,120,000		598,120,000
Income from discontinued operations		592,395,000		591,448,000
Income tax expense		(51,910,000)		(51,910,000)
Total income from discontinued operations		$ 540,485,000		$ 539,538,000