Note 7 - Leases and Deferred Rent - Supplemental Cash Flow Information Related to Leases (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jan. 01, 2019	Dec. 31, 2018
Rent expense	$ 192	$ 227	$ 363	$ 473
Operating cash flows from operating leases			356
Operating leases
Operating Lease, Right-of-Use Asset	2,684		2,684		$ 2,966
Current portion of operating lease liabilities, included in accrued liabilities	551		551
Operating lease liabilities, net of current portion	2,269		2,269
Total operating lease liabilities	$ 2,820		$ 2,820		$ 3,101
Weighted average remaining lease term for operating leases (in years) (Year)	4 years 328 days		4 years 328 days
Weighted average discount rate for operating leases	6.10%		6.10%