Discontinued Operations - Schedule of Discontinued Operations (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Other income and expenses:
Loss from discontinued operations	$ 0	$ (947,000)
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		3,730,000
Selling, general and administrative expenses		8,733,000
Restructuring expenses		5,265,000
Total costs and expenses		21,618,000
Other income and expenses:
Interest expense		(5,234,000)
Loss from discontinued operations		$ (947,000)