Note 7 - Income Taxes - Reconciliation of the Statutory U.S. Federal Income Tax Rate to the Consolidated Effective Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Statutory U.S. federal income tax rate	21.00%	21.00%
Increase (decrease) in rate due to:
Non-U.S. income tax differential	0.20%	19.90%
U.S. state and local income taxes, net of related U.S. federal income taxes	0.30%	22.60%
U.S. federal credits	1.40%	(9.80%)
Permanent adjustments	(1.90%)	27.70%
Foreign withholding taxes	(1.00%)	75.90%
Valuation allowances	(9.60%)	143.50%
Unrecognized tax benefits	0.70%	48.40%
Impact of foreign exchange	(1.60%)	71.60%
Asset impairments	(17.60%)
Other	(6.40%)	25.60%
Consolidated effective income tax rate	(14.50%)	446.40%