Note 10 - Taxes on Income (Details Textual) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Effective Income Tax Rate Reconciliation, Percent, Total	1.80%	1275.00%		(143.30%)	22.90%
Effective Income Tax Rate Reconciliation, Tax Cuts and Jobs Act, Transition Tax on Accumulated Foreign Earnings, Amount	$ 1.7		$ 1.5
Effective Income Tax Rate Reconciliation, Tax Credit, Foreign, Percent	27.00%
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Payment Arrangement, Amount			$ 1.5	$ 2.1
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Percent, Total					39.30%

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Percentage of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations attributable to nondeductible expenses.

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