Accrued Expenses and Other Current Liabilities - Summary of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Payables And Accruals [Abstract]
Development and manufacturing costs	$ 625	$ 598
Payroll and payroll-related costs	1,382	547
Professional fees	281	314
Facility and other	469	278
Total Accrued Expenses and Other Current Liabilities	$ 2,757	$ 1,737