The lower R&D expenses in 2020 were principally due to a net decrease in costs associated with clinical trials and travel costs, partially offset by a $2.5 million milestone payment made in connection with a license agreement within tariffs, increase in payroll and related costs, and increases in stock compensation expense.

Feb 25, 2021 / CFO / receipt, needs a key / Thomas Riley, CFO | earnings call 2021-02-25 | transcript ebf3fe3e-cdf5-4ad4-b55e-3bf7ee440a31 | chars 11586-11911 | segment 11