Note 11 - Income Taxes - Reconciliation of Income Tax Rate (Details)
12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Dec. 31, 2019
Federal statutory rate 21.00% 21.00% 21.00%
Foreign rate differential (0.10%) (0.90%) (2.90%)
State income taxes, net of federal benefit (3.50%) (2.90%) 2.90%
Nondeductible transaction costs 0.00% 0.00% 0.70%
Tax indemnification charges 1.00% 1.00% 7.90%
Stock Compensation 1.40% 1.00% 1.00%
Other differences 0.10% 0.60% 4.10%
Withholding tax 1.20% 0.20% 3.30%
Rate changes (6.40%) 0.00% 0.00%
Tax credits (5.20%) 3.10% (2.40%)
Uncertain tax positions (5.80%) (2.80%) (26.00%)
Valuation allowance 29.40% 15.30% 0.30%
Effective tax rate (8.90%) (6.40%) (32.10%)