Accrued Expenses - Schedule of Accrued Expensest (Detail) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Accrued Liabilities Current [Abstract]
Accrued wages and benefits	$ 6,277	$ 5,061
Accrued clinical expenses	2,848	2,653
Accrued operating expenses	5,994	8,128
Deferred revenue	20,071	190
Accrued R&D licensing fees	382	4,827
Accrued tax withholdings	256
Accrued selling fees and rebates	1,436	423
Accrued construction costs	32,730	16,436
Total accrued expenses	$ 69,994	$ 37,718