Accrued Expenses and Other Liabilities - Schedule of Accrued Expenses and Other Liabilities (Detail) - USD ($)	Dec. 31, 2019	Dec. 31, 2018
Payables and Accruals [Abstract]
Accrued preclinical and clinical trial expenses	$ 1,183,513	$ 821,633
Accrued professional fees	1,241,526	1,311,061
Accrued compensation and benefits	3,064,645	1,941,449
Accrued license fees	8,751,991	3,000,000
Accrued purchases	1,313,310
Accrued contributions	1,535,000
Operating lease liability	300,518
Accrued variable consideration	884,764
Deferred rent and lease incentive	0	33,408
Income tax payable	1,533,696
Other	172,332	66,436
Current accrued expenses and other liabilities	19,981,295	7,173,987
Lease liability - non-current	647,532
Deferred rent and lease incentive - non-current	0	154,799
Non-current accrued expenses and other liabilities	647,532	154,799
Total accrued expenses and other liabilities	$ 20,628,827	$ 7,328,786