Note 8 - Commitments and Contingencies - Supplemental Lease Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Right-of-use asset, net and lease liabilities (in thousands)	$ 3,170		$ 3,170		$ 945
Cash paid for operating lease liabilities (in thousands)			$ 754		$ 563
Weighted average remaining lease term (years) (Year)	3 years 219 days		3 years 219 days		1 year 36 days
Weighted average discount rate	3.90%		3.90%		5.50%
Lease expense	$ 300	$ 148	$ 754	$ 413
Cost of Sales [Member]
Lease expense	218	78	508	201
General and Administrative Expense [Member]
Lease expense	52	52	157	157
Research and Development Expense [Member]
Lease expense	$ 30	$ 18	$ 89	$ 55