Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity - Additional Information (Detail)

v3.21.1
Stockholders' Equity - Additional Information (Detail)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 17, 2020
USD ($)
$ / shares
shares
Jul. 17, 2020
shares
Jul. 16, 2020
shares
Apr. 10, 2020
USD ($)
d
$ / shares
shares
Dec. 12, 2019
USD ($)
$ / shares
shares
Mar. 08, 2018
$ / shares
shares
Sep. 30, 2016
$ / shares
shares
Jun. 21, 2016
$ / shares
shares
Dec. 31, 2020
USD ($)
$ / shares
shares
Dec. 31, 2019
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
shares
Jun. 18, 2019
shares
Jun. 17, 2019
shares
May 07, 2014
$ / shares
shares
Schedule Of Capitalization Equity [Line Items]                            
Common stock, par value (in dollars per share) | $ / shares                 $ 0.001 $ 0.001        
Common stock, shares authorized (in shares)   100,000,000 250,000,000           100,000,000 100,000,000   250,000,000 125,000,000  
Common stock, shares issued (in shares)   10,508,302 105,083,291           19,663,698 9,741,372        
Common stock, shares outstanding (in shares)   10,508,302 105,083,291           19,663,698 9,741,372        
Common stock, reverse stock split                 1-for-10          
Reverse stock split, ratio     0.1                      
Stock issued during period as result of reverse stock splits   0 0                      
Preferred stock, shares authorized (in shares)                 5,000,000 5,000,000       5,000,000
Preferred stock, par value (in dollars per share) | $ / shares                 $ 0.001 $ 0.001       $ 0.001
Preferred stock, shares issued (in shares)                 0 0        
Preferred stock, shares outstanding (in shares)                 0 0        
Common stock issued, net of expenses (in shares)           1,775,150   937,500            
Proceeds from common stock issued | $                 $ 90,554 $ 46,337        
Common stock issued, net of expenses | $                 57,184 30,530        
Warrant liabilities fair value adjustment | $                 5,214 $ 4,497        
Warrant liabilities | $                 $ 51,200          
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              
Aspire Capital | Common Stock Purchase Agreement                            
Schedule Of Capitalization Equity [Line Items]                            
Common stock issued, net of expenses (in shares)                 125,000          
Proceeds from common stock issued | $                 $ 600          
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%                    
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 | d       3                    
Stock purchase price number of consecutive trading days | d       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%                    
Option to Purchase Common Stock                            
Schedule Of Capitalization Equity [Line Items]                            
Options expiration date         2020-01                  
Maximum | Aspire Capital | Common Stock Purchase Agreement                            
Schedule Of Capitalization Equity [Line Items]                            
Public offering price | $ / shares       $ 0.25                    
Sale of common stock at sole discretion | $       $ 20,000                    
Stock purchase percentage on aggregate shares of common stock traded       30.00%                    
Maximum | Option to Purchase Common Stock                            
Schedule Of Capitalization Equity [Line Items]                            
Number of options not exercised         583,333                  
Series 1 Warrant                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares)                     11,550      
Warrants, expiration date           Mar. 14, 2019                
Proceeds from Warrant Exercises | $                     $ 200      
Common Stock                            
Schedule Of Capitalization Equity [Line Items]                            
Common stock, shares outstanding (in shares)                 19,663,698 9,741,372 4,797,198      
Common stock issued, net of expenses (in shares)                 9,156,304 4,773,692        
Common stock issued, net of expenses | $                 $ 9 $ 5        
Commitment Shares | Aspire Capital | Common Stock Purchase Agreement                            
Schedule Of Capitalization Equity [Line Items]                            
Common stock shares issued       70,910                    
Commitment Shares | Aspire Capital | Common Stock Purchase Agreement | Other Expense                            
Schedule Of Capitalization Equity [Line Items]                            
Fair value of shares | $                 600          
December 2020 Public Offering                            
Schedule Of Capitalization Equity [Line Items]                            
Common stock, par value (in dollars per share) | $ / shares $ 0.001                          
Common stock issued, net of expenses (in shares) 8,340,000                          
Exercise price of warrants (in dollars per share) | $ / shares $ 0.001                          
Number of shares received per warrant (in shares) 6,800,000                          
Proceeds from common stock issued | $ $ 79,500                          
Warrant liabilities fair value adjustment | $                 1,900          
December 2020 Public Offering | Pre-funded Warrants                            
Schedule Of Capitalization Equity [Line Items]                            
Common stock, par value (in dollars per share) | $ / shares $ 0.001                          
Number of warrants issued to purchase common stock (in shares) 5,260,000                          
Public offering price | $ / shares $ 6.249                          
December 2020 Public Offering | Series 1 Warrant                            
Schedule Of Capitalization Equity [Line Items]                            
Exercise price of warrants (in dollars per share) | $ / shares $ 7.33                          
Warrant term 1 year                          
December 2020 Public Offering | Series 1 Warrant | Maximum                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares) 13,600,000                          
December 2020 Public Offering | Series 2 Warrant                            
Schedule Of Capitalization Equity [Line Items]                            
Exercise price of warrants (in dollars per share) | $ / shares $ 8.25                          
Warrant term 3 years 6 months                          
December 2020 Public Offering | Series 2 Warrant | Minimum                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares) 5,260,000                          
December 2020 Public Offering | Common Stock                            
Schedule Of Capitalization Equity [Line Items]                            
Public offering price | $ / shares $ 6.25                          
December 2019 Public Offering                            
Schedule Of Capitalization Equity [Line Items]                            
Common stock issued, net of expenses (in shares)         3,888,888                  
Number of warrants issued to purchase common stock (in shares)         3,888,888                  
Exercise price of warrants (in dollars per share) | $ / shares         $ 11.0                  
Share price (in dollars per share) | $ / shares         $ 9.00                  
Common stock issued, net of expenses | $         $ 32,500                  
Warrants, expiration date         Jun. 12, 2023                  
Warrant liabilities fair value adjustment | $                 $ 1,000          
Underwriters | Maximum                            
Schedule Of Capitalization Equity [Line Items]                            
Option to purchase shares of common stock         583,333                  
Underwriters | Warrant liability                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares)         583,333                  
Number of warrants exercised         583,333                  
March 2018 Public Offering                            
Schedule Of Capitalization Equity [Line Items]                            
Public offering price | $ / shares           $ 16.90                
March 2018 Public Offering | Series 1 Warrant                            
Schedule Of Capitalization Equity [Line Items]                            
Exercise price of warrants (in dollars per share) | $ / shares           $ 18.5                
Number of shares received per warrant (in shares)           0.75                
Warrant term           371 days                
March 2018 Public Offering | Series 1 Warrant | Maximum                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares)           1,331,370                
March 2018 Public Offering | Series 2 Warrant                            
Schedule Of Capitalization Equity [Line Items]                            
Exercise price of warrants (in dollars per share) | $ / shares           $ 20.0                
Number of shares received per warrant (in shares)           0.45                
Warrant term           5 years                
March 2018 Public Offering | Series 2 Warrant | Maximum                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares)           798,810                
March 2018 Public Offering | Warrant liability | Maximum                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares)           2,130,180                
June 2016 Public Offering                            
Schedule Of Capitalization Equity [Line Items]                            
Exercise price of warrants (in dollars per share) | $ / shares               $ 30.0            
Number of shares received per warrant (in shares)               0.45            
Warrant expiration period               5 years            
June 2016 Public Offering | Warrant liability | Maximum                            
Schedule Of Capitalization Equity [Line Items]                            
Number of warrants issued to purchase common stock (in shares)               421,867