Note 7 - Income Taxes - Deferred Tax Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Net operating loss carryforwards	$ 14,507	$ 11,227
Stock-based compensation	1,111	1,040
Other accruals and reserves	2,202	1,924
Credits	11,888	10,857
Foreign		457
Accrued warranty	924	1,863
Depreciation and amortization	2,354	2,024
Other	897	282
Operating Lease Asset	3,949
Deferred tax asset before valuation allowance	37,831	29,674
Valuation allowance	(32,350)	(27,865)
Deferred tax asset after valuation allowance	5,482	1,809
Deferred tax liability on Accrued commissions 606 cost	(1,076)	(1,269)
Deferred tax liability on goodwill	(97)	(83)
Operating Lease Liability	(3,885)
Net deferred tax asset	$ 424	$ 457