Accrued Expenses (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Accrued Expenses
Payroll and related costs	$ 381	$ 477
Clinical and nonclinical trial expenses	2,436	2,909
Professional and consulting fees	430	591
Other	95	111
Total accrued expenses	$ 3,342	$ 4,088