Annual report pursuant to Section 13 and 15(d)

Convertible Notes Payable - Additional Information (Detail)

v3.8.0.1
Convertible Notes Payable - Additional Information (Detail) - USD ($)
 1 Months Ended 3 Months Ended 12 Months Ended
May 17, 2017
Apr. 30, 2017
May 31, 2017
Apr. 30, 2017
Mar. 31, 2017
Mar. 31, 2017
Dec. 31, 2017
Dec. 31, 2016
May 16, 2017
Debt Instrument [Line Items]                  
Number of warrants issued             1,122,840 2,552,068  
Fair market value of warrants               $ 7,114,000  
Common stock issued             13,538,080    
Debt discounts associated with stock warrants               6,793,000  
Charges recorded on issuance of additional common stock and warrants               $ 159,000  
Common Stock [Member]                  
Debt Instrument [Line Items]                  
Common stock issued               106,420  
Bridge Loan [Member]                  
Debt Instrument [Line Items]                  
Fair market value of warrants             $ 6,534,000    
Accrued interest $ 45,000                
Warrants to purchase common stock 313,440               240,000
Fully diluted shares outstanding percentage 1.50%                
Shares converted to common stock 590,717                
Note Purchase Agreement [Member]                  
Debt Instrument [Line Items]                  
Common stock issued         120,000        
Primary Warrant [Member]                  
Debt Instrument [Line Items]                  
Fair market value of warrants               $ 8,064,000  
Bridge Loan [Member]                  
Debt Instrument [Line Items]                  
Debt instrument principal balance             $ 0    
Borrowing under line of credit         $ 2,000,000        
Common stock issued         90,000        
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        
Shares converted to common stock             590,717    
Bridge Loan [Member] | Common Stock [Member]                  
Debt Instrument [Line Items]                  
Common stock issued             300,000    
Shares converted to common stock             590,717    
Bridge Loan [Member] | Note Purchase Agreement [Member] | VLOC, LLC [Member]                  
Debt Instrument [Line Items]                  
Line of credit, interest rate         8.00%        
Borrowing under line of credit         $ 2,000,000        
Common stock issued           120,000      
Initial Public Offering [Member]                  
Debt Instrument [Line Items]                  
Common stock issued 2,500,000           2,500,000    
Acacia [Member]                  
Debt Instrument [Line Items]                  
Debt instrument principal balance             $ 0    
Warrants to purchase common stock             1,524,573    
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                
Shares converted to common stock 590,717                
Acacia [Member] | Primary Warrant [Member]                  
Debt Instrument [Line Items]                  
Warrants maturity period 5 years                
Warrants to purchase common stock 809,400                
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  
Number of warrants issued               3  
Warrants maturity period               4 years  
Fair market value of warrants               $ 841,000  
Accrued interest $ 737,000                
Shares converted to common stock 1,523,746           1,523,746    
Acacia [Member] | Bridge Loan [Member]                  
Debt Instrument [Line Items]                  
Debt instrument principal balance   $ 8,000,000 $ 8,000,000 $ 8,000,000 $ 8,000,000 $ 8,000,000      
Borrowing under line of credit   $ 2,000,000 $ 4,000,000            
Common stock issued 180,000                
Acacia [Member] | Initial Public Offering [Member]                  
Debt Instrument [Line Items]                  
Fair market value of warrants $ 5,790,000                
Acacia [Member] | Initial Public Offering [Member] | Convertible Notes Payable [Member]                  
Debt Instrument [Line Items]                  
Debt instrument principal balance 20,000,000                
Accrued interest $ 737,000                
Shares 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] | Initial Public Offering [Member] | Convertible Notes Payable [Member] | Bridge Loan [Member]                  
Debt Instrument [Line Items]                  
Debt instrument principal balance $ 8,000,000                
Accrued interest $ 45,000                
Shares converted to common stock 13.6088                
Borrowing under line of credit $ 4,000,000                
Debt discounts associated with stock warrants 2,915,000                
Acacia [Member] | Initial Public Offering [Member] | Convertible Notes Payable [Member] | Bridge Loan [Member] | Common Stock [Member]                  
Debt Instrument [Line Items]                  
Charges recorded on issuance of additional common stock and warrants 1,100,000                
Acacia [Member] | Initial Public Offering [Member] | Convertible Notes Payable [Member] | Bridge Loan [Member] | Warrant [Member]                  
Debt Instrument [Line Items]                  
Charges recorded on issuance of additional common stock and warrants $ 1,770,000