Quarterly report pursuant to Section 13 or 15(d)

Stockholder's Equity - Additional Information (Detail)

v3.20.2
Stockholder's Equity - Additional Information (Detail)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Jul. 17, 2020
shares
Jul. 16, 2020
shares
Apr. 10, 2020
USD ($)
TradingDay
$ / shares
shares
Sep. 30, 2016
$ / shares
shares
Sep. 30, 2020
USD ($)
$ / shares
shares
Sep. 30, 2019
USD ($)
Sep. 30, 2020
USD ($)
$ / shares
shares
Sep. 30, 2019
USD ($)
Dec. 31, 2019
$ / shares
shares
Schedule Of Capitalization Equity [Line Items]                  
Common stock, par value (in dollars per share) | $ / shares         $ 0.001   $ 0.001   $ 0.001
Common stock, shares authorized (in shares) 100,000,000 250,000,000     100,000,000   100,000,000   100,000,000
Common stock, shares issued (in shares) 10,508,302 105,083,291     10,798,119   10,798,119   9,741,372
Common stock, shares outstanding (in shares) 10,508,302 105,083,291     10,798,119   10,798,119   9,741,372
Common stock, reverse stock split             1-for-10    
Common stock, reverse stock split ratio   0.1              
Number of fractional shares issued result of reverse stock split 0 0              
Proceeds from common stock issued | $             $ 4,702 $ 10,069  
Derivative liability fair value adjustment | $         $ 5,290 $ 2,324 6,683 223  
Warrant liabilities fair value adjustment | $         (7,786) (1,830) (16,114) 2,643  
Warrant liabilities | $         2,300   2,300    
Warrants to purchase common stock associated with Loan Agreement                  
Schedule Of Capitalization Equity [Line Items]                  
Number of warrants issued to purchase common stock (in shares)       12,243          
Exercise price of warrants (in dollars per share) | $ / shares       $ 36.754          
Warrant expiration period       5 years          
Other (Income) Expense | Senior Convertible Note Purchase Agreement                  
Schedule Of Capitalization Equity [Line Items]                  
Derivative liability fair value adjustment | $         $ 5,300 $ 2,300 $ 6,700 $ 200  
Aspire Capital | Common Stock Purchase Agreement                  
Schedule Of Capitalization Equity [Line Items]                  
Sale of common stock at sole discretion | $     $ 20,000            
Number of purchase aggregate shares of common stock     1,956,547            
Percentage of common stock outstanding     19.99%            
Number of shares committed     70,910            
Average purchase price of shares sold | $ / shares     $ 8.461            
Percentage of common stock owned     19.99%            
Common stock issued, net of expenses (in shares)         125,000   125,000    
Proceeds from common stock issued | $         $ 600   $ 600    
Sale of common stock maximum number of share sold per business day     25,000            
Stock purchase price average number of trading days lowest closing sales price out of consecutive trading days | TradingDay     3            
Stock purchase price number of consecutive trading days | TradingDay     10            
Increase in sale of common stock maximum number of share sold per business day     200,000            
Percentage of purchase price per share     97.00%            
Aspire Capital | Common Stock Purchase Agreement | Commitment Shares                  
Schedule Of Capitalization Equity [Line Items]                  
Common stock shares issued     70,910            
Aspire Capital | Common Stock Purchase Agreement | Commitment Shares | Other Expense                  
Schedule Of Capitalization Equity [Line Items]                  
Fair value of shares | $             $ 600    
Aspire Capital | Common Stock Purchase Agreement | Maximum                  
Schedule Of Capitalization Equity [Line Items]                  
Sale of common stock at sole discretion | $     $ 20,000            
Percentage of common stock outstanding     19.99%            
Stock purchase percentage on aggregate shares of common stock traded     30.00%            
Closing sale price of common stock | $ / shares     $ 0.25