Annual report pursuant to Section 13 and 15(d)

Convertible Notes Payable - Additional Information (Detail)

v3.19.1
Convertible Notes Payable - Additional Information (Detail) - USD ($)
1 Months Ended 12 Months Ended
Jun. 25, 2018
Nov. 21, 2017
May 17, 2017
May 31, 2017
Apr. 30, 2017
Mar. 31, 2017
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
May 16, 2017
Debt Instrument [Line Items]                    
Common stock issued 1,955,000 1,121,250       120,000        
Warrants to purchase common stock             1,297,151 1,524,573    
Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Fair market value of warrants             $ 6,534,000      
Warrants to purchase common stock     313,440             240,000
Fully diluted shares outstanding percentage     1.50%              
Common Stock [Member]                    
Debt Instrument [Line Items]                    
Common stock issued             1,955,000 3,621,250    
Common Stock [Member] | Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Common stock issued         210,000 210,000        
Initial Public Offering [Member]                    
Debt Instrument [Line Items]                    
Common stock issued     2,500,000              
Primary Warrant [Member]                    
Debt Instrument [Line Items]                    
Fair market value of warrants                 $ 8,064,000  
Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Warrants to purchase common stock     313,440             240,000
Fully diluted shares outstanding percentage     1.50%              
Amortization of debt discount         $ 3,664,000 $ 3,664,000        
Bridge Loan [Member] | Common Stock [Member]                    
Debt Instrument [Line Items]                    
Common stock issued               300,000    
Bridge Loan [Member] | VLOC, LLC [Member] | Note Purchase Agreement [Member]                    
Debt Instrument [Line Items]                    
Line of credit, interest rate           8.00%        
Borrowing under line of credit           $ 2,000,000        
Acacia [Member] | Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Debt instrument principal balance     $ 4,000,000              
Common stock issued     90,000              
Warrants to purchase common stock     120,000              
Acacia [Member] | Primary Warrant [Member] | Maximum [Member]                    
Debt Instrument [Line Items]                    
Warrants exercise price value                 50,000,000  
Acacia [Member] | Convertible Notes Payable [Member]                    
Debt Instrument [Line Items]                    
Debt instrument principal balance     $ 20,000,000           $ 20,000,000  
Debt instrument interest rate                 6.00%  
Debt instrument maturity date                 Nov. 30, 2017  
Fair market value of warrants                 $ 841,000  
Accrued interest     737,000              
Acacia [Member] | Convertible Notes Payable [Member] | Initial Public Offering [Member]                    
Debt Instrument [Line Items]                    
Debt instrument principal balance     20,000,000              
Accrued interest     $ 737,000              
Debt instrument converted to common stock     1,523,746              
Conversion price per share     $ 13.6088              
Write off of unamortized balance of debt discounts associated with stock warrants               $ 4,347,000    
Acacia [Member] | Convertible Notes Payable [Member] | Initial Public Offering [Member] | Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Debt instrument principal balance     $ 8,000,000              
Accrued interest     $ 45,000              
Debt instrument converted to common stock     590,717              
Conversion price per share     $ 13.6088              
Borrowing under line of credit     $ 4,000,000              
Debt discounts associated with stock warrants               $ 2,915,000    
Acacia [Member] | Convertible Notes Payable [Member] | Initial Public Offering [Member] | Common Stock [Member] | Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Charges recorded on issuance of additional common stock and warrants     1,100,000              
Acacia [Member] | Convertible Notes Payable [Member] | Initial Public Offering [Member] | Warrant [Member] | Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Charges recorded on issuance of additional common stock and warrants     $ 1,770,000              
Acacia [Member] | Bridge Loan [Member]                    
Debt Instrument [Line Items]                    
Debt instrument principal balance       $ 8,000,000 8,000,000 $ 8,000,000        
Borrowing under line of credit       $ 4,000,000 $ 2,000,000          
Common stock issued     180,000