Riverbed, Inc. established a stock-appreciation rights (SARs) program on January 1, 2020, which entitles executives to receive cash at the date of exercise for the difference between the market price of the stock and the pre-established price of $21 on 5,100 SARs. The required service period is 2 years. The fair value of the SARs are determined to be $5 on December 31, 2020, and $10 on December 31, 2021. Compute Riverbed's compensation expense for 2020 and 2021. Riverbed's compensation expense 2020 Riverbed's compensation expense for 2021 LA $ $ LA