Note 15 - Income Taxes (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		21.00%	35.00%
Effective Income Tax Rate Reconciliation, Tax Expense (Benefit), Share-based Payment Arrangement, Amount		$ (2,828,000)	$ 415,000	$ 2,832,000
Effective Income Tax Rate Reconciliation, Change in Unrecognized Tax Benefits		(1,571,000)	4,680,000	75,000
Income Tax Expense (Benefit), Continuing Operations, Adjustment of Deferred Tax (Asset) Liability	$ 10,000,000.0
Deferred Tax Assets, Valuation Allowance, Total		6,498,000	7,598,000
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		(1,100,000)
Liability for Uncertainty in Income Taxes, Current		8,900,000	10,400,000
Unrecognized Tax Benefits that Would Impact Effective Tax Rate		3,300,000	3,500,000
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense, Total		(1,500,000)	$ 1,900,000	$ 0.0
Minimum [Member]
Decrease in Unrecognized Tax Benefits is Reasonably Possible		0.0
Maximum [Member]
Decrease in Unrecognized Tax Benefits is Reasonably Possible		200,000
Domestic Tax Authority [Member] | Internal Revenue Service (IRS) [Member]
Operating Loss Carryforwards, Total		$ 0
Open Tax Year		2016 2017 2018 2019
State and Local Jurisdiction [Member]
Operating Loss Carryforwards, Total		$ 10,100,000
Open Tax Year		2015 2016 2017 2018 2019