Note 8 - Commitments and Contingencies (Details Textual) - USD ($)	3 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Operating Lease, Weighted Average Discount Rate, Percent	3.90%		5.50%
Operating Lease, Weighted Average Remaining Lease Term (Year)	3 years 292 days		1 year 36 days
Operating Lease, Expense	$ 291,000	$ 142,000
Cost of Sales [Member]
Operating Lease, Expense	212,000	73,000
General and Administrative Expense [Member]
Operating Lease, Expense	52,000	52,000
Research and Development Expense [Member]
Operating Lease, Expense	27,000	$ 17,000
Accounting Standards Update 2016-02 [Member]
Operating Lease, Right-of-Use Asset	3,336,000		$ 945,000
Operating Lease, Liability, Total	$ 3,336,000		$ 945,000