Note 6 - Income Taxes - Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Allowance for uncollectable accounts	$ 79	$ 53
Inventories reserve	348	267
Accrued vacation	112	145
Accrued bonus	171
Stock-based compensation and equity appreciation rights	62	54
Lease Accounting ASC 842 Lease Liability	1,230
Section 481(a) adjustment	716	(249)
Net operating loss carryforwards	97	175
Tax credit carryforwards	171	449
Other	7	76
Total	2,993	970
Valuation allowance	(1,403)	(614)
Deferred tax (liabilities) assets	1,590	356
Prepaid expenses		(40)
Lease Accounting ASC 842 Lease Asset	(1,158)
Property and equipment	(432)	(316)
Deferred tax liabilities	(1,590)	(356)
Net deferred tax assets