Accrued Liabilities - Summary of Accrued Liabilities (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accrued employee bonuses	$ 884,871	$ 2,150,418
Payroll and employee benefit accruals	399,728	698,969
Accrued professional fees	29,490	60,400
Accrued interest	221,284	156,492
Other accrued liabilities	259,756	292,186
Total accrued liabilities	$ 1,795,129	$ 3,358,465