Share-Based Compensation - Summary of Share-based Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
2016 Employee Stock Purchase Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 14	$ 719
2016 Employee Stock Purchase Plan | Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	8	306
2016 Employee Stock Purchase Plan | General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	6	413
Stock Options | 2011 Stock Incentive Plan, 2016 Equity Incentive Plan
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	799	719
Stock Options | 2011 Stock Incentive Plan, 2016 Equity Incentive Plan | Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	377	306
Stock Options | 2011 Stock Incentive Plan, 2016 Equity Incentive Plan | General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	422	413
Restricted Stock Units (RSUs)
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	341	719
Restricted Stock Units (RSUs) | Research and Development
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	171	306
Restricted Stock Units (RSUs) | General and Administrative
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Share-based compensation expense	$ 170	$ 413