Note 10 - Segment and Geographic Data - Summary of Operations by Geographic Area (Details) - USD ($)	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Product sales, net	$ 1,811,386	$ 1,915,909
Product sales, net	43,242
Dental Segment [Member]
Product sales, net	1,803,586	1,915,509
Medical Segment [Member]
Product sales, net	7,800	400
Domestic [Member]
Product sales, net	720,391	930,364
Domestic [Member] | Devices [Member]
Product sales, net	525	123,994
Domestic [Member] | Handpieces [Member]
Product sales, net	697,360	789,553
Domestic [Member] | Other Products [Member]
Product sales, net	22,506	16,817
Domestic [Member] | Dental Segment [Member]
Product sales, net	720,391	929,964
Domestic [Member] | Dental Segment [Member] | Devices [Member]
Product sales, net	525	123,994
Domestic [Member] | Dental Segment [Member] | Handpieces [Member]
Product sales, net	697,360	789,153
Domestic [Member] | Dental Segment [Member] | Other Products [Member]
Product sales, net	22,506	16,817
Domestic [Member] | Medical Segment [Member]
Product sales, net		400
Domestic [Member] | Medical Segment [Member] | Devices [Member]
Product sales, net
Domestic [Member] | Medical Segment [Member] | Handpieces [Member]
Product sales, net		400
Domestic [Member] | Medical Segment [Member] | Other Products [Member]
Product sales, net
Rest of World [Member]
Product sales, net	1,090,995	935,545
Rest of World [Member] | Devices [Member]
Product sales, net	250,104	285,345
Rest of World [Member] | Handpieces [Member]
Product sales, net	830,408	631,311
Rest of World [Member] | Other Products [Member]
Product sales, net	10,483	18,889
Rest of World [Member] | Dental Segment [Member]
Product sales, net	1,083,195	935,545
Rest of World [Member] | Dental Segment [Member] | Devices [Member]
Product sales, net	242,504	285,345
Rest of World [Member] | Dental Segment [Member] | Handpieces [Member]
Product sales, net	830,208	631,311
Rest of World [Member] | Dental Segment [Member] | Other Products [Member]
Product sales, net	10,483	18,889
Rest of World [Member] | Medical Segment [Member]
Product sales, net	7,800
Rest of World [Member] | Medical Segment [Member] | Devices [Member]
Product sales, net	7,600
Rest of World [Member] | Medical Segment [Member] | Handpieces [Member]
Product sales, net	200
Rest of World [Member] | Medical Segment [Member] | Other Products [Member]
Product sales, net
CHINA
Product sales, net		50,000
Product sales, net
CHINA | Devices [Member]
Product sales, net
CHINA | Handpieces [Member]
Product sales, net		50,000
CHINA | Other Products [Member]
Product sales, net
CHINA | Dental Segment [Member]
Product sales, net		50,000
Product sales, net
CHINA | Dental Segment [Member] | Devices [Member]
Product sales, net
CHINA | Dental Segment [Member] | Handpieces [Member]
Product sales, net		50,000
CHINA | Dental Segment [Member] | Other Products [Member]
Product sales, net
CHINA | Medical Segment [Member]
Product sales, net
Product sales, net
CHINA | Medical Segment [Member] | Devices [Member]
Product sales, net
CHINA | Medical Segment [Member] | Handpieces [Member]
Product sales, net
CHINA | Medical Segment [Member] | Other Products [Member]
Product sales, net