Accrued Expenses and Other Liabilities - Summary of Accrued Expenses and Other Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Payables And Accruals [Abstract]
Accrued contracted research and development costs	$ 2,946	$ 1,308
Accrued general and administrative costs	578	323
Accrued compensation	388	1,328
Other		7
Total accrued expenses and other liabilities	$ 3,912	$ 2,966

Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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