Development and License Agreements - Summary of Prepaid R&D Asset and Manufacturing Efficiency Asset (Detail) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Other current assets
Deferred Costs Capitalized Prepaid And Other Assets [Line Items]
Prepaid R&D asset - current	[1]	$ 114	$ 923
Other assets
Deferred Costs Capitalized Prepaid And Other Assets [Line Items]
Prepaid R&D asset - current	[2]	2,162	1,984
Manufacturing efficiency asset	[2]	$ 1,839	$ 2,085

[1] Included in “Other current assets” in the Company's consolidated balance sheets.

[2] Included in “Other assets” in the Company's consolidated balance sheets.