Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Accumulated deficit	$ (419,716)	$ (446,252)
Accounting Standards Update 2016-13 | Revision of Prior Period Accounting Standards Update Adjustment
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Accumulated deficit	$ 1,000