Note 15 - Restructuring Charges and (Reversals) - Restructuring Liabilities (Details) - USD ($)	1 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cumulative cost incurred		$ 4,071,000
Balance		3,648,000
Period charges		122,000	4,920,000
Cash paid, net of receipts		(2,799,000)	(1,272,000)	$ (41,000)
Period reversals		(971,000)
Balance			3,648,000
Contract Termination [Member]
Cumulative cost incurred		2,252,000
Balance		3,223,000
Period charges			3,223,000
Cash paid, net of receipts	$ (2,252,000)	(2,252,000)
Period reversals		(971,000)
Balance			3,223,000
Employee Severance [Member]
Cumulative cost incurred		368,000
Balance		368,000
Period charges			368,000
Cash paid, net of receipts		(368,000)
Period reversals
Balance			368,000
Impairment Charges [Member]
Cumulative cost incurred		1,272,000
Balance
Period charges			1,272,000
Cash paid, net of receipts			(1,272,000)
Period reversals
Balance
Other Restructuring [Member]
Cumulative cost incurred		179,000
Balance		57,000
Period charges		122,000	57,000
Cash paid, net of receipts		(179,000)
Period reversals
Balance			$ 57,000