Note 10 - Leases (Details Textual)	3 Months Ended
	Mar. 31, 2019 USD ($)
Operating Lease, Weighted Average Discount Rate, Percent	6.50%
Finance Lease, Weighted Average Discount Rate, Percent	8.10%
Operating Lease, Weighted Average Remaining Lease Term	2 years 109 days
Finance Lease, Weighted Average Remaining Lease Term	1 year 328 days
Operating Lease, Cost	$ 142,000
Operating Lease, Payments	$ 186,000
Bothell, Washington Headquarters [Member]
Lessee, Operating Lease, Renewal Term	5 years