3. REVENUE FROM CONTRACTS WITH CUSTOMERS (Details - Contract balances) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Billings In Excess Of Costs And Estimated Earnings On Uncompleted Contracts And Deferred Revenues
Costs incurred on uncompleted contracts	$ 2,098	$ 1,687
Estimated earnings on uncompleted contracts	3,153	2,294
Gross costs and estimated earnings	5,251	3,981
Less: Billings to date on uncompleted contracts	(5,792)	(3,790)
Costs incurred plus estimated earning less billings on uncompleted contracts, net	(541)	191
Included in the accompanying condensed consolidated balance sheets under the following captions:
Contract Assets	189	814
Contract Liabilities	(730)	(623)
Costs incurred plus estimated earning less billings on uncompleted contracts	$ (541)	$ 191