Note 3 - Revenue Recognition

12 Months Ended

Dec. 31, 2020

Notes to Financial Statements

Revenue from Contract with Customer [Text Block]

3.

     REVENUE RECOGNITION

Disaggregated Revenue by Product Technology

The following table presents our revenues disaggregated by product technology:

	Twelve Months Ended December 31,
	2020		2019
Air Pollution Control
Technology solutions	$	5,668	$	10,640
Spare parts		906		1,031
Ancillary revenue		1,983		2,411
Total Air Pollution Control Technology		8,557		14,082
FUEL CHEM
FUEL CHEM technology solutions		13,993		16,385
Total Revenues	$	22,550	$	30,467

Disaggregated Revenue by Geography

The following table presents our revenues disaggregated by geography, based on the billing addresses of our customers:

	Twelve Months Ended December 31,
	2020		2019
United States	$	18,622	$	25,882
Foreign Revenues
Americas		549		777
Europe		1,656		2,322
Asia		1,723		1,486
Total Foreign Revenues		3,928		4,585
Total Revenues	$	22,550	$	30,467

Timing of Revenue Recognition

The following table presents the timing of our revenue recognition:

	Twelve Months Ended December 31,
	2020		2019
Products transferred at a point in time	$	15,787	$	19,827
Products and services transferred over time		6,763		10,640
Total Revenues	$	22,550	$	30,467

Contract Balances

The timing of revenue recognition, billings and cash collections results in billed accounts receivable, unbilled receivables (contract assets), and customer advances and deposits (contract liabilities) on the consolidated balance sheets. In our Air Pollution Control Technology segment, amounts are billed as work progresses in accordance with agreed-upon contractual terms. Generally, billing occurs subsequent to revenue recognition, resulting in contract assets. These assets are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. At

December 31, 2020

and

2019

, contract assets were approximately

$2,348

 and

$1,857,

respectively, and are included in accounts receivable on the consolidated balance sheets.

However, the Company will periodically bill in advance of costs incurred before revenue is recognized, resulting in contract liabilities. These liabilities are reported on the consolidated balance sheet on a contract-by-contract basis at the end of each reporting period. Contract liabilities were

$850

 and

$712

at

December 31, 2020

and

2019

, respectively, and are included in other accrued liabilities on the consolidated balance sheets.

As of

December 31, 2020

we had

one

 construction contract in progress that was identified as a loss contract and a provision for losses of

$176

was recorded in other accrued liabilities on the consolidated balance sheet. As of

December 31, 2019

, we had

three

construction contracts in progress that were identified as loss contracts and a provision for losses of

$26

 was recorded in other accrued liabilities on the consolidated balance sheet.

Remaining Performance Obligations

Remaining performance obligations, represents the transaction price of Air Pollution Control technology booked orders for which work has

not

been performed. As of

December 31, 2020

, the aggregate amount of the transaction price allocated to remaining performance obligations was

$5,268.

The Company expects to recognize revenue on approximately

$2,981

 of the remaining performance obligations over the next

12

months with the remaining recognized thereafter.

Practical Expedients and Exemptions

We generally expense sales commissions on a ratable basis when incurred because the amortization period would have been

one

year or less. These costs are recorded within selling, general and administrative expenses within the Consolidated Statements of Operations. A practical expedient was elected to

not

recognize shipping and handling costs as a separate performance obligation under ASC

606.

Accounts Receivable

The components of accounts receivable are as follows:

	As of
	December 31, 2020			December 31, 2019
Trade receivables	$	5,015		$	6,425
Unbilled receivables		2,348			1,857
Other short-term receivables		20			7
Allowance for doubtful accounts		(835	)		(1,816	)
Total accounts receivable	$	6,548		$	6,473