Quarterly report pursuant to Section 13 or 15(d)

Stock Warrants - Schedule of Warrants Outstanding (Detail)

v3.21.2
Stock Warrants - Schedule of Warrants Outstanding (Detail) - $ / shares
6 Months Ended
Jun. 30, 2021
Dec. 31, 2020
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 12,327,304 12,350,293
Weighted-average exercise price per share $ 9.14 $ 9.14
Other Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants [1] 2,138 2,567
Pfizer [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 505,617 505,617
Exercise Price Less Than or Equal to $10.00 [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 9,326,092  
Expiration Start Date Sep. 01, 2021  
Expiration End Date May 27, 2023  
Exercise Price Greater Than $10.00 Lesser Than Equal To $20.00 [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,599,645  
Expiration End Date Jul. 25, 2022  
Exercise Price Greater Than or Equal to $ 20.00 [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,401,567  
Expiration Start Date Jul. 27, 2021  
Expiration End Date Jan. 05, 2022  
Minimum [Member] | Exercise Price Less Than or Equal to $10.00 [Member]    
Class of Warrant or Right [Line Items]    
Exercise Prices $ 10.00  
Minimum [Member] | Exercise Price Greater Than $10.00 Lesser Than Equal To $20.00 [Member]    
Class of Warrant or Right [Line Items]    
Exercise Prices 10.00  
Maximum [Member] | Exercise Price Greater Than $10.00 Lesser Than Equal To $20.00 [Member]    
Class of Warrant or Right [Line Items]    
Exercise Prices 20.00  
Maximum [Member] | Exercise Price Greater Than or Equal to $ 20.00 [Member]    
Class of Warrant or Right [Line Items]    
Exercise Prices $ 20.00  
2016 Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,400,000 1,400,000
2017 Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 1,599,645 1,599,645
2020 Warrants [Member]    
Class of Warrant or Right [Line Items]    
Shares Underlying Outstanding Warrants 8,819,904 8,842,464
[1] Other warrants are comprised of warrants issued prior to the Company’s initial public offering (“IPO”), generally in exchange for services rendered to the Company.