Prepaid Expenses and Other Current Assets - Prepaid Expenses and Other Current Assets (Detail) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Deferred Costs, Capitalized, Prepaid, and Other Assets Disclosure [Abstract]
Prepaid manufacturing costs	$ 3,471,078	$ 1,526,013
Prepaid insurance	995,146	1,263,129
Prepaid subscriptions fees	492,716	501,251
Prepaid research fees	490,102	481,057
Prepaid commercialization expenses	287,083	62,959
Other	326,590	516,665
Total prepaid expenses and other current assets	$ 6,062,715	$ 4,351,074