v3.24.0.1
Stockholders' Equity - Additional Information (Detail) - USD ($)
1 Months Ended 3 Months Ended 12 Months Ended
Feb. 28, 2023
Mar. 31, 2022
Sep. 30, 2021
Sep. 30, 2020
Mar. 31, 2022
Dec. 31, 2023
Dec. 31, 2022
Dec. 31, 2021
Apr. 30, 2022
Mar. 31, 2021
Nov. 30, 2020
May 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Commission Rate Equal To Gross Proceeds1                 3.00% 3.00%    
Number of common stock shares reserved for issuance           8,813,251            
Stock options granted           1,112,885            
Weighted average grant date fair value of options granted           $ 1.59 $ 2.49 $ 3.82        
Total grant date fair value of restricted stock units vested           $ 0 $ 597,000 $ 16,000        
Aggregate intrinsic value of stock options exercised           0 1,000 80,000        
Aggregate intrinsic value of restricted stock units           123,875 $ 6,000 $ 31,000        
Unrecognized share based compensation expense related to unvested stock options           4,600,000            
Unrecognized share based compensation expense related to restricted stock units           $ 200,000            
Inducement Pool Non Qualified Option [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of common stock shares reserved for issuance   300,000     300,000              
Employee Stock Option [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Unrecognized cost expected to be recognized over a weighted average period           2 years 3 months 18 days            
Restricted Stock Unit [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Unrecognized cost expected to be recognized over a weighted average period           2 years            
2014 Plan [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Maximum term for stock option plan grant           10 years            
Options vesting period           4 years            
2015 Stock Option and Incentive Plan [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Maximum term for stock option plan grant           10 years            
Options vesting period           4 years            
Options vesting period, description           For an initial grant to an employee, 25% of the options generally vest on the first anniversary of the original vesting date, with the balance vesting monthly over the remaining three years. For subsequent grants to an employee, the options generally vest monthly over a four-year term.            
2015 Stock Option and Incentive Plan [Member] | One Year Anniversary [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Option vesting percentage           25.00%            
Aspire Capital [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares issued and sold           0 0 3,000,000        
Shares Issued, Price Per Share               $ 5.09        
Proceeds from Issuance of Common Stock               $ 15,200,000        
Long-term purchase commitment, description       upon the terms and subject to the conditions and limitations set forth therein, Aspire Capital was committed to purchase up to an aggregate of $20.0 million of shares of our common stock at our request from time to time during the 30 month term of the Purchase Agreement.                
Commitment to purchase shares       $ 20,000,000                
Long-term purchase commitment, period       30 months                
Public Offerings [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Proceeds from Issuance of Common Stock $ 48,100,000   $ 80,600,000                  
ATM Offering Program [Member] | H.C. Wainwright & Co., LLC [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Proceeds from Issuance of Common Stock               $ 9,600,000        
Commission Rate Equal To Gross Proceeds1                       3.00%
ATM Offering Program [Member] | H.C. Wainwright & Co., LLC [Member] | Sale Agreement [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Agreed upon value of sale of common stock per transaction                   $ 20,000,000    
ATM Offering Program [Member] | H.C. Wainwright & Co., LLC [Member] | Sale Agreement [Member] | Maximum [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Agreed upon value of sale of common stock per transaction                     $ 20,000,000 $ 10,000,000
ATM Offering Program [Member] | Jefferies LLC [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Shares Issued, Price Per Share           $ 1.82 $ 3.09          
Proceeds from Issuance of Common Stock           $ 18,400,000 $ 4,000,000          
ATM Offering Program [Member] | Jefferies LLC [Member] | Sale Agreement [Member] | Maximum [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Agreed upon value of sale of common stock per transaction                 $ 65,000,000      
ATM Offering Program [Member] | Jones Trading Institutional Services LLC [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Shares Issued, Price Per Share   $ 6.07     $ 6.07     $ 4.75        
Proceeds from Issuance of Common Stock         $ 1,500,000     $ 4,400,000        
ATM Offering Program [Member] | Jones Trading Institutional Services LLC [Member] | Sale Agreement [Member] | Maximum [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Agreed upon value of sale of common stock per transaction                   $ 25,000,000    
IPO [Member] | 2015 Stock Option and Incentive Plan [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of common stock shares reserved for issuance           3,964,555            
IPO [Member] | 2015 Employee Stock Purchase Plan [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of common stock shares reserved for issuance           727,311            
Common Stock [Member] | Inducement Pool Non Qualified Option [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Options vesting period   4 years                    
Stock options granted           23,400            
Exercise price, granted           $ 2.26            
Common Stock [Member] | One Year Anniversary [Member] | Inducement Pool Non Qualified Option [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Options vesting period   1 year                    
Option vesting percentage   25.00%                    
Common Stock [Member] | Share-Based Payment Arrangement, Tranche Two [Member] | Inducement Pool Non Qualified Option [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Options vesting period   3 years                    
Option vesting percentage   75.00%                    
Common Stock [Member] | Maximum [Member] | Inducement Pool Non Qualified Option [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Options vesting period   10 years                    
Common Stock [Member] | Public Offerings [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares issued and sold 23,125,000   10,781,250                  
Shares Issued, Price Per Share $ 2.25   $ 8                  
Common Stock [Member] | ATM Offering Program [Member] | H.C. Wainwright & Co., LLC [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares issued and sold               1,988,254        
Shares Issued, Price Per Share               $ 4.99        
Common Stock [Member] | ATM Offering Program [Member] | Jefferies LLC [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares issued and sold           10,530,795 1,421,627          
Common Stock [Member] | ATM Offering Program [Member] | Jones Trading Institutional Services LLC [Member]                        
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                        
Number of shares issued and sold         260,455     986,267