Note 1 - Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Notes Tables

Financing Receivable, Allowance for Credit Loss [Table Text Block]

	2019			2018
Allowance for doubtful accounts at the beginning of the period	$	971,772		$	660,581
Bad debt expense		25,044			353,562
Receivables written off during the periods		(362,244	)		-
Effect of currency translation		(22,138	)		(42,371	)
Allowance for doubtful accounts at the end of the period	$	612,434		$	971,772

Schedule of Revenue from External Customers Attributed to Foreign Countries by Geographic Area [Table Text Block]

	For the Year Ended December 31
	2019		2018
United States and Canada	$	1,600,298	$	922,245
Australia		425,560		597,214
South America		-		49,861
Asia		5,991,440		1,369,735
Europe		24,620,186		9,293,033
	$	32,637,484	$	12,232,088

Reconciliation of Revenue from Segments to Consolidated [Table Text Block]

	For the Year Ended December 31
	2019		2018
Ceramic diesel particulate	$	5,652,686	$	6,536,085
Liquid filters and systems		25,464,614		5,264,663
Plastics		895,203		-
Development projects		625,981		431,340
	$	32,637,484	$	12,232,088

Contract with Customer, Asset and Liability [Table Text Block]

	2019			2018
Cost incurred	$	3,960,199		$	2,066,982
Prepayments		(1,732,231	)		(1,959,042	)
Deferred Revenue		(876,286	)		(98,781	)
Allowance for doubtful accounts at the end of the period	$	1,351,682		$	9,159
Distributed as follows:
Contract Assets		2,773,058			624,275
Contract Liabilities		(1,421,376	)		(615,116	)
		1,351,682			9,159