Annual report pursuant to Section 13 and 15(d)

Stock Based Compensation - Summary of Stock-based Compensation Reflected within Statements of Operations (Detail)

v3.20.1
Stock Based Compensation - Summary of Stock-based Compensation Reflected within Statements of Operations (Detail) - USD ($)
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Share-based Compensation, Total $ 10,646,580 $ 16,753,754
Research and Development Expense [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Allocated share-based compensation expense 5,419,627 9,676,156
Selling and Marketing Expense [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Allocated share-based compensation expense 1,561,319 1,416,136
General and Administrative Expense [Member]    
Share-based Compensation Arrangement by Share-based Payment Award, Compensation Cost [Line Items]    
Allocated share-based compensation expense $ 3,665,634 $ 5,661,462