Accrued Expenses and Other Current Liabilities - Schedule of Accrued Expenses and Other Current Liabilities (Detail) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Payables And Accruals [Abstract]
Research and development	$ 3,565	$ 1,856
Payroll and other employee-related expenses	6,301	10,674
Professional services fees	2,688	2,094
Accrued interest	3,145	1,464
Product revenue reserves	4,010	2,990
Accrual for employee stock purchase plan	733	235
Foreign withholding taxes payable	495	495
Other	516	200
Total accrued expenses and other current liabilities	$ 21,453	$ 20,008