Note 14 - Significant Customers / Concentration - Sales by Product Line (Details) - USD ($)	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016
Net Sales	$ 11,343,177	$ 13,906,394
Ceramic Diesel Particulate [Member]
Net Sales	7,230,416	5,820,793
Liquid Filters [Member]
Net Sales	3,987,424	7,731,079
Kiln Furniture [Member]
Net Sales	$ 125,337	$ 354,522

Aggregate revenue during the period from the sale of goods in the normal course of business, after deducting returns, allowances and discounts.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(a))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Name:	us-gaap_SalesRevenueGoodsNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration