v3.19.3
Notes Payable - Schedule of Notes Payable (Detail) - USD ($)
Sep. 30, 2019
May 31, 2019
Dec. 31, 2018
Nov. 30, 2018
Oct. 31, 2018
Jan. 31, 2018
Debt Instrument [Line Items]            
Total face amount $ 24,215,000   $ 9,117,000      
Unamortized discount (4,956,000)   (1,780,000)     $ (271,000)
Total carrying value 19,259,000   7,337,000      
Amount classified as current 16,544,000   4,464,000      
Amount classified as long-term 2,715,000   2,873,000      
8% Secured Promissory Notes Due August 2018 [Member]            
Debt Instrument [Line Items]            
Total face amount     250,000      
0% Convertible Notes Due January 2021 [Member]            
Debt Instrument [Line Items]            
Total face amount 275,000   275,000      
4% Promissory Note Due April 2021 [Member]            
Debt Instrument [Line Items]            
Total face amount 704,000   847,000      
0% Promissory Note Due April 2019 [Member]            
Debt Instrument [Line Items]            
Total face amount     418,000      
8% Promissory Note Due March 2021 [Member]            
Debt Instrument [Line Items]            
Total face amount 2,107,000   2,107,000      
12% Convertible Notes Due October 2019 [Member]            
Debt Instrument [Line Items]            
Total face amount 4,000,000   4,000,000      
Unamortized discount         $ (1,942,000)  
12% Convertible Notes Due November 2019 [Member]            
Debt Instrument [Line Items]            
Total face amount 1,220,000   $ 1,220,000      
Unamortized discount       $ (118,000)    
12% Convertible Notes Due May 2020 [Member]            
Debt Instrument [Line Items]            
Total face amount 3,500,000          
Unamortized discount   $ (940,000)        
12% Convertible Notes Due July 2020 [Member]            
Debt Instrument [Line Items]            
Total face amount 350,000          
12% Convertible Notes Due August 2020 [Member]            
Debt Instrument [Line Items]            
Total face amount 350,000          
12% Convertible Notes Due September 2020 [Member]            
Debt Instrument [Line Items]            
Total face amount 3,851,000          
12% Secured Promissory Note Due September 2020 [Member]            
Debt Instrument [Line Items]            
Total face amount $ 7,858,000