Note 7 - Notes Payable - New Credit Facility (Details) - USD ($)	Dec. 31, 2018	Dec. 03, 2018	Dec. 31, 2017	Feb. 17, 2016
Debt issuance cost, current		$ (2,100,000)
Debt issuance cost				$ (15,000)
Notes payable, net of debt issuance cost, current	$ 3,904,000		$ 3,891,000
Notes payable, net of debt issuance cost, long-term	69,107,000		80,058,000
Notes payable, net of debt issuance cost	74,562,000
New Credit Facility [Member]
Notes payable, current	4,350,000
Notes payable, long-term	70,212,000
Notes payable, face amount	74,562,000		85,912,000
Debt issuance cost, current	(446,000)
Debt issuance cost, long-term	(1,105,000)
Debt issuance cost	(1,551,000)		(1,963,000)
Notes payable, net of debt issuance cost, current	3,904,000
Notes payable, net of debt issuance cost, long-term	69,107,000
Notes payable, net of debt issuance cost	$ 73,011,000		$ 83,949,000