Quarterly report pursuant to Section 13 or 15(d)

Fair Value Measurements - Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail)

v3.19.3
Fair Value Measurements - Information about Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)
Sep. 30, 2019
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Marketable securities   $ 22,131,936
Warrant liabilities $ (2,159,192) (20,781,663)
Fair Value, Measurements, Recurring [Member] | Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Cash equivalents 8,688,134 6,850,772
Marketable securities   22,131,936
Total assets (liabilities) 8,688,134 28,982,708
Fair Value, Measurements, Recurring [Member] | Level 3 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]    
Warrant liabilities 2,159,192 20,781,663
Total assets (liabilities) $ 2,159,192 $ 20,781,663