Annual report pursuant to Section 13 and 15(d)

Common Stock - Issued and Outstanding Shares - Additional Information (Detail)

v3.22.0.1
Common Stock - Issued and Outstanding Shares - Additional Information (Detail) - USD ($)
12 Months Ended 40 Months Ended
May 27, 2021
Dec. 07, 2020
Aug. 06, 2020
Jul. 01, 2020
Apr. 28, 2020
Mar. 12, 2020
Dec. 17, 2019
May 22, 2018
Sep. 14, 2017
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2020
Aug. 03, 2020
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, par value                   $ 0.001 $ 0.001     $ 0.001  
Common stock, shares issued                   9,453,542 6,111,735     6,111,735  
Preferred stock, par value                   $ 0.001          
Proceeds from exercise of warrants                   $ 338,000 $ 3,231,000 $ 4,199,000      
Shares issued                   $ 41,000          
Stock option exercises, Shares                   0 0        
Restricted stock unit settlements                   231 236        
Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued                   5,114          
Restricted stock unit settlements                   145 128   254    
December 2019 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant             $ 6.60                
Offering expenses                     $ 34,000        
Warrant exercisable period             5 years                
Cancellation of warrant description                   Additionally, subject to certain exceptions, if, after December 17, 2019, (i) the volume weighted average price of the common stock for each of 30 consecutive trading days, or the 2019 Measurement Period, which 2019 Measurement Period commences on the closing date, exceeds 300% of the exercise price (subject to adjustments for stock splits, recapitalizations, stock dividends and similar transactions), (ii) the average daily trading volume for such 2019 Measurement Period exceeds $500,000 per trading day and (iii) certain other equity conditions are met, and subject to a beneficial ownership limitation, then we may call for cancellation of all or any portion of the warrants then outstanding.          
Number of required consecutive days weighted average trading price for cancelation or recall of warrants             30 days                
Minimum required trading price percentage over exercise price for cancelation or recall of warrants             300.00%                
Minimum required trading volume value per day for cancelation or recall of warrants             $ 500,000                
Gross proceeds from sale of warrants and units                   $ 13,800,000          
Warrant and units offering cost including underwriting discounts and commissions                   1,500,000          
Net proceeds from issuance of warrants and units                   $ 12,300,000          
Gross proceeds from issuance of common stock   $ 17,300,000                          
Proceeds from issuance of common stock   15,800,000                          
Underwriting discounts and commissions and offering expenses   $ 1,500,000                          
December 2019 Public Offering [Member] | Representative's Warrant [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Number of common shares issuable conversion of warrants   50,000                          
Common stock, price per share   $ 8.75                          
Adjustments to additional paid in capital   $ 300,000                          
Warrant exercisable term   5 years                          
December 2019 Public Offering [Member] | Maximum [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant             $ 1.2                
April 2020 Private Placement [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued         280,782                    
Number of required consecutive days weighted average trading price for cancelation or recall of warrants                   30 days          
Warrants to purchase shares of common stock         0.75                    
Warrants to purchase shares of common stock, offering price per share         $ 6.60                    
Gross proceeds from issuance of common stock         $ 1,900,000                    
Proceeds from exercise of warrants         $ 1,600,000                    
Percentage of exercise price exceeds in measurement period                   300.00%          
Average daily trading volume for measurement period                   $ 500,000          
Shares issued                     $ 1,579,000        
April 2020 Private Placement [Member] | Placement Agent [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant         $ 7.59                    
Number of common shares issuable conversion of warrants         25,270                    
April 2020 Private Placement [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued                     280,782        
Shares issued                     $ 6,000        
July 2020 Registered Direct Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Gross proceeds from issuance of common stock       $ 6,000,000.0                      
Placement agent fees and offering expenses       700,000                      
Proceeds from issuance of common stock       $ 5,300,000                      
Shares issued                     $ 5,307,000        
July 2020 Registered Direct Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued       731,707             731,707        
Common stock, price per share       $ 8.20                      
Shares issued                     $ 15,000        
August 2020 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Gross proceeds from issuance of common stock     $ 7,500,000                        
Proceeds from issuance of common stock     6,800,000               6,822,000        
Underwriting discounts and commissions and offering expenses     $ 700,000                        
Shares issued                     $ 6,822,000        
August 2020 Public Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued     569,043               569,043        
Common stock, price per share                             $ 10.50
Shares issued                     $ 1,000        
Underwriters Over-Allotment Option Exercise [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued 428,571 322,500 92,856                        
December 2020 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Proceeds from issuance of common stock                     15,789,000        
Shares issued                     $ 15,789,000        
December 2020 Public Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued   2,472,500                 2,472,500        
Common stock, price per share   $ 7.00                          
Shares issued                     $ 2,000        
May 2021 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Gross proceeds from issuance of common stock $ 23,000,000.0                            
Proceeds from issuance of common stock 21,300,000                            
Underwriting discounts and commissions and offering expenses $ 1,700,000                            
May 2021 Public Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued 3,285,714                            
Common stock, price per share $ 7.00                            
At-the-Market Sales Agreement [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued                   0          
Shares issued                   $ 25,000,000          
Common stock available for sale under offering                   $ 25,000,000.0          
Series A Convertible Preferred Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Preferred stock, par value                   $ 0.001 $ 0.001     $ 0.001  
Preferred stock, shares outstanding                   0 0     0  
Series B Convertible Preferred Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Preferred stock, par value                   $ 0.001 $ 0.001     $ 0.001  
Preferred stock, shares outstanding                   0 0     0  
Series B Convertible Preferred Stock [Member] | December 2019 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Preferred stock, shares converted                   6,256          
Preferred stock, shares outstanding                   0          
Series B Convertible Preferred Stock [Member] | December 2019 Public Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Convertible preferred stock, shares issued upon conversion                   521,124          
Subscription Agreements Executed on April 27, 2020 [Member] | April 2020 Private Placement [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant                   $ 7.24          
Subscription Agreements Executed on April 28, 2020 [Member] | April 2020 Private Placement [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant                   $ 7.32          
Class A Units [Member] | December 2019 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Issuance of new units in a public offering             478,875                
Public offering, price per unit             $ 12.00                
Description of stock units issued                   Each Class A Unit consisted of one share of our common stock and a warrant to purchase one share of common stock.          
Class B Units [Member] | December 2019 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Issuance of new units in a public offering             6,256                
Public offering, price per unit             $ 999.60                
Description of stock units issued                   Each Class B Unit consisted of one share of Series B Convertible Preferred Stock, par value $0.001 per share, convertible at any time at the holder’s option into 83 shares of common stock, and warrants to purchase 83 shares of common stock.          
Number of common shares issuable for each share of convertible preferred stock             83                
Number of common shares issuable conversion of warrants             83                
Class B Units [Member] | Series A Convertible Preferred Stock [Member] | December 2019 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Preferred stock, par value             $ 0.001                
Pre Funded Warrants | August 2020 Public Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Number of common shares issuable conversion of warrants     142,857                        
Pre-funded warrant, offering price per share                             10.499
Pre Funded Warrants | August 2020 Public Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant                             $ 0.001
Number of days of prior notice to achieve not in excess percentage of common stock shares owned by warrant holder     61 days                        
Pre Funded Warrants | August 2020 Public Offering [Member] | Maximum [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Percentage of shares of common stock owned by warrant holder     19.99%                        
Pre Funded Warrants | August 2020 Public Offering [Member] | Minimum [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Percentage of shares of common stock owned by warrant holder     9.99%                        
LPC [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock value right to sell, maximum           $ 11,000,000.0                  
Common stock, par value           $ 0.001                  
Minimum percentage of common stock shares outstanding authorized to sell               20.00%              
Initial purchase of common stock                           1,644  
Common stock, shares issued                 617            
Payments related to expense reimbursement           $ 100,000                  
Common stock, shares issued                   0       27,868  
Gross proceeds                           $ 4,400,000  
Offering expenses                           $ 500,000  
Purchase agreement expired date                   Mar. 14, 2022          
LPC [Member] | Purchase Agreement [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, purchase price                 $ 1.00            
Additional common stock value right to sell, maximum                 $ 10,000,000.0            
Additional purchase of common stock, maximum                 7,500            
Offering expenses                     $ 14,000        
LPC [Member] | Units [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Initial purchase of common stock                 1,644            
Common stock, purchase price                 $ 608            
Purchase agreement, description                   Unit consisting of (a) one share of our common stock and (b) one warrant to purchase one-quarter of a share of common stock at an exercise price of $699.20 per share, or Warrant.  Each Warrant became exercisable six months following the issuance date until the date that is five years and six months after the issuance date and is subject to customary adjustments.          
Exercise price per unit of warrant                 $ 699.20            
Initial purchase of units consisting of common stock and warrants issued                 $ 1,000,000.0            
LPC [Member] | Other Units [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Number of warrants issued                 0            
Ladenburg Thalmann & Co. Inc [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Period granted for underwriting option             45 days                
Ladenburg Thalmann & Co. Inc [Member] | 2019 Overallotment Option [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Additional purchase of common stock and warrants, maximum             150,000                
Overallotment option exercise date             Dec. 17, 2019