Schedule of Adoption of New Revenue Guidance Impact on Condensed Consolidated Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues:
Net revenue - commercial product sales	$ 4,469	$ 2,043	$ 11,827	$ 7,215
Expenses:
Cost of goods sold	5,303	4,575	14,406	12,210
Net loss	(24,168)	(32,886)	(77,224)	(84,549)
Adjustments | Accounting Standards Update 2014-09
Expenses:
Cost of goods sold	(790)		(975)
Net loss	(137)		(196)
Balances Without Adoption of Topic 606 | Accounting Standards Update 2014-09
Expenses:
Cost of goods sold	4,513		13,431
Net loss	(24,305)		(77,420)
Net revenue - commercial product sales
Revenues:
Net revenue - commercial product sales	4,387	$ 1,981	11,542	$ 4,726
Net revenue - commercial product sales | Adjustments | Accounting Standards Update 2014-09
Revenues:
Net revenue - commercial product sales	(654)		(778)
Net revenue - commercial product sales | Balances Without Adoption of Topic 606 | Accounting Standards Update 2014-09
Revenues:
Net revenue - commercial product sales	$ 3,733		$ 10,764