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Fair Value of Financial Assets and Liabilities - Additional Information (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Nov. 30, 2019
Jun. 30, 2017
Mar. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Total cash $ 3,000,000 $ 5,400,000        
Fair value assets level 1 to level 2 transfers 0 0        
Fair value assets level 2 to level 1 transfers 0 0        
Fair value liabilities level 1 to level 2 transfers 0 0        
Fair value liabilities level 2 to level 1 transfers 0 0        
Transfer of financial asset into level 3 of fair value 0 0        
Transfer of financial liabilities into level 3 of fair value $ 0 $ 0        
Anti-dilution rights outstanding 5,730,178 5,517,810        
Spero Gyrase, Inc. [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Percentage of minority investor outstanding shares repurchased       100.00%    
Repurchase price per share $ 0.001     $ 0.001    
Anti-dilution rights outstanding 0          
Spero Gyrase, Inc. [Member] | Anti-dilution Rights [Member]            
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]            
Derivative liabilities         $ 200,000 $ 1,600,000
Increase (decrease) derivative liabilities     $ (1,400,000)