Quarterly report pursuant to Section 13 or 15(d)

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

v3.19.1
Common Stock - Issued and Outstanding Shares - Additional Information (Detail) - USD ($)
 3 Months Ended 19 Months Ended
Mar. 31, 2019
Oct. 03, 2018
Jun. 19, 2018
Jun. 15, 2018
May 22, 2018
Sep. 14, 2017
Mar. 31, 2019
Mar. 31, 2018
Mar. 31, 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               $ 1,105,000      
Common stock, shares issued 6,721,200           6,721,200   6,721,200 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 the June 19, 2018, (i) the volume weighted average price of our common stock for each of 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 579           579   579 579  
Stock option exercises, Shares             0 0      
Restricted stock unit settlements             133 0      
Common Stock                      
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                      
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 8,579                    
Preferred stock, shares outstanding 579           579   579    
Series A Convertible Preferred Stock [Member] | Common Stock                      
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]                      
Convertible preferred stock, shares issued upon conversion 2,144,750                    
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%            
Initial purchase of common stock                 32,895    
Common stock, shares issued           12,352          
Proceeds from issuance of common stock           $ 0          
Common stock, shares issued                 183,378    
Gross proceeds                 $ 3,600,000    
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