Summary of Other Current Assets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Jul. 31, 2016
Prepaid Expense And Other Assets Current [Abstract]
Manufacturing-related deposits and prepaids	$ 15,049	$ 18,650
Prepaid clinical and preclinical expenses	6,103	5,175
Prepaid maintenance and license fees	2,442	1,711
Prepaid research expenses	2,140	2,896
Prepaid commercial expenses	883	1,589
Asset held for sale		1,501	$ 1,500
Other prepaids	2,186	2,726
Other	2,400	2,263
Total other current assets	$ 31,203	$ 36,511