Note 10 - Activity of Business Segments - Reconciliation of Total Segment Income to Total Consolidated Net Income (Details) - USD ($)	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consolidated net income	$ 508,000	$ 550,000
Provision for income taxes	92,000	222,000
Operating Segments [Member]
Consolidated net income	2,017,000	2,016,000
Operating Segments [Member] | Building Supply [Member]
Consolidated net income	994,000	962,000
Operating Segments [Member] | Disposable Protective Apparel [Member]
Consolidated net income	290,000	458,000
Operating Segments [Member] | Infection Control [Member]
Consolidated net income	733,000	596,000
Corporate, Non-Segment [Member]
Consolidated net income	$ 1,417,000	$ 1,244,000