Note 2 - Revenue Recognition - Contract Assets and Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Deferred revenue	$ 2,507	$ 871
Acquired in Dielectrics business combination		2,175
Increases due to consideration received from customers	3,216	4,188
Revenue recognized	(3,149)	(4,727)
Deferred revenue	2,574	2,507
Unbilled Receivables - beginning of period	65
Increases due to revenue recognized - not invoiced to customers	831	301
Decreases due to customer invoicing	(824)	(236)
Unbilled Receivables - end of period	$ 72	$ 65