Schedule of Adoption of New Revenue Guidance Impact on Consolidated Statement of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues:
Net revenue - commercial product sales	$ 16,031	$ 4,469	$ 3,893	$ 3,465	$ 4,530	$ 2,043	$ 2,163	$ 3,009	$ 27,859	$ 11,745	$ 174,758
Expenses:
Cost of goods sold									19,402	17,228	17,121
Net loss	$ (9,747)	$ (24,168)	$ (22,675)	$ (30,385)	$ (32,784)	$ (32,886)	$ (35,339)	$ (16,324)	(86,975)	(117,333)	125,664
Commercial product sales
Revenues:
Net revenue - commercial product sales									17,276	$ 9,192	$ 1,895
Adjustments | Accounting Standards Update 2014-09
Expenses:
Cost of goods sold									(754)
Net loss									(267)
Adjustments | Commercial product sales | Accounting Standards Update 2014-09
Revenues:
Net revenue - commercial product sales									(486)
Balances Without Adoption of Topic 606 | Accounting Standards Update 2014-09
Expenses:
Cost of goods sold									18,648
Net loss									(87,242)
Balances Without Adoption of Topic 606 | Commercial product sales | Accounting Standards Update 2014-09
Revenues:
Net revenue - commercial product sales									$ 16,790