Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.2
Common Stock - Issued and Outstanding Shares - Additional Information (Detail) - USD ($)
 3 Months Ended 6 Months Ended 23 Months Ended
Jun. 30, 2019
Jun. 07, 2019
Oct. 03, 2018
Jun. 19, 2018
Jun. 15, 2018
May 22, 2018
Sep. 14, 2017
Jun. 30, 2019
Mar. 31, 2019
Jun. 30, 2018
Jun. 30, 2019
Jun. 30, 2018
Aug. 08, 2019
Dec. 31, 2018
May 23, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, par value $ 0.001             $ 0.001     $ 0.001     $ 0.001 $ 0.001
Exercise price per unit of warrant       $ 4.00                      
Initial purchase of units consisting of common stock and warrants issued                     $ 423,000 $ 1,280,000      
Common stock, shares issued 8,097,763             8,097,763     8,097,763     6,721,117  
Preferred stock, par value $ 0.001             $ 0.001     $ 0.001     $ 0.001  
Warrant exercisable period       5 years                      
Cancellation of warrant description                     Additionally, subject to certain exceptions, if, after June 19, 2018, (i) the volume weighted average price of our common stock for each of any 30 consecutive trading days, or the Measurement Period, which Measurement Period commences on June 19, 2018, 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 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                     1,600,000        
Net proceeds from issuance of warrants and units                     $ 12,200,000        
Preferred stock, shares outstanding 0             0     0     579  
Stock option exercises, Shares               0   0 0 0      
Restricted stock unit settlements               133   0 133 0      
Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Restricted stock unit settlements                 83            
Direct Offering [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Proceeds from issuance of common stock     $ 5,000,000                        
Gross proceeds from issuance of common stock     5,600,000                        
Placement agent fees and offering expenses     $ 600,000                        
Direct Offering [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, shares issued     1,789,258                        
Common stock, price     $ 3.1445                        
Private Placement [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Exercise price per unit of warrant     $ 3.1445                        
Warrant exercisable period     5 years                        
Maximum number of common shares issuable per warrant upon conversion     0.5                        
Series A Convertible Preferred Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Preferred stock, shares converted 9,158                            
Preferred stock, shares outstanding 0             0     0        
Series A Convertible Preferred Stock [Member] | Common Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Convertible preferred stock, shares issued upon conversion 2,289,500                            
Class A Units [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Issuance of new units in a public offering       710,500                      
Public offering, price per unit       $ 4.00                      
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]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Issuance of new units in a public offering       9,158                      
Public offering, price per unit       $ 1,000                      
Description of stock units issued                     Each Class B Unit consisted of one share of Series A Convertible Preferred Stock par value $0.001 per share, convertible at any time at the holder’s option into 250 shares of common stock and warrants to purchase 250 shares of common stock.        
Number of common shares issuable for each share of convertible preferred stock       250                      
Number of common shares issuable conversion of warrants       250                      
Class B Units [Member] | Series A Convertible Preferred Stock [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Preferred stock, par value       $ 0.001                      
LPC [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock value right to sell, maximum             $ 11,000,000                
Common stock, par value             $ 0.001                
Minimum percentage of common stock shares outstanding authorized to sell           20.00%                  
Common stock, shares issued             12,352                
Proceeds from issuance of common stock             $ 0                
Common stock, shares issued               124,000     124,000        
Gross proceeds               $ 400,000     $ 400,000        
Common stock remaining available for sale under offering $ 6,900,000             6,900,000     $ 6,900,000        
LPC [Member] | Subsequent Event [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Initial purchase of common stock                         32,895    
Common stock, shares issued                         307,378    
Gross proceeds                         $ 4,100,000    
Offering expenses                         $ 500,000    
LPC [Member] | Minimum [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, purchase price             $ 20.00                
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                
Additional purchase of common stock, maximum             8,000                
LPC [Member] | Units [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Initial purchase of common stock             32,895                
Common stock, purchase price             $ 30.40                
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 $34.96 per share, or Warrant. Each Warrant is 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             $ 34.96                
Initial purchase of units consisting of common stock and warrants issued             $ 1,000,000                
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] | Overallotment Option [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Additional purchase of common stock and warrants, maximum         450,000                    
Overallotment option exercise date         Jun. 18, 2018                    
H.C. Wainwright [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock, par value   $ 0.001                          
Common stock remaining available for sale under offering $ 6,000,000             $ 6,000,000     $ 6,000,000        
Percentage of commission on gross proceeds from sale of common stock   3.00%                          
H.C. Wainwright [Member] | Maximum [Member]                              
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                              
Common stock value right to sell, maximum   $ 6,000,000