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Key Assumptions Used to Value the Warrants (Detail)
Mar. 31, 2021
$ / shares
Dec. 31, 2020
$ / shares
May 31, 2016
$ / shares
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Stock price $ 7.32    
PIPE Warrants      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Stock price $ 7.32 $ 5.77 $ 8.90
PIPE Warrants | Measurement Input, Price Volatility      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Expected price volatility 159.96 56.79 76.25
PIPE Warrants | Measurement Input, Expected Term      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Expected term (in years) 3 months 6 months 5 years
PIPE Warrants | Measurement Input, Risk Free Interest Rate      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Expected price volatility 0.03 0.09 1.22
PIPE Warrants | Measurement Input, Expected Dividend Rate      
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]      
Expected price volatility 0 0 0