Accounts Payable and Accrued Expenses - Summary of Accounts Payable and Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Payables And Accruals [Abstract]
Accounts payable - trade	$ 492	$ 285
Payroll and benefits	1,290	1,096
Inventory	1,143	0
Research and development	629	433
Royalty fees due to unrelated parties	226	187
Consulting	397	92
Rent and utilities	23	91
Audit and tax fees	113	23
Legal	138	285
Other	234	153
Total accounts payable and accrued expenses	$ 4,685	$ 2,645