Significant Accounting Policies (Tables)

9 Months Ended

Feb. 29, 2020

Accounting Policies [Abstract]

Schedule of Inventory, Current [Table Text Block]

	February 29, 2020		May 31, 2019
Raw materials	$	1,102,000	$	1,208,000
Work in progress		900,000		771,000
Finished products		186,000		172,000
Total	$	2,188,000	$	2,151,000

Share-based Payment Arrangement, Option, Activity [Table Text Block]

		Exercise Price Weighted Average
	Option Shares
Outstanding May 31, 2019	1,476,209	$	2.07
Granted	356,000	$	2.79
Exercised	(80,375)	$	1.01
Cancelled or expired	(47,500)	$	3.25
Outstanding February 29, 2020	1,704,334	$	2.24

Disaggregation of Revenue [Table Text Block]

	Nine Months ended				Three Months ended
	February 29, 2020		February 28, 2019		February 29, 2020		February 28, 2019
Clinical lab	$	2,769,000	$	3,150,000	$	723,000	$	1,043,000
OTC		778,000		653,000		271,000		131,000
Physicians’ office		157,000		142,000		32,000		48,000
Contract Manufacturing		264,000		90,000		151,000		39,000
Total	$	3,968,000	$	4,035,000	$	1,177,000	$	1,261,000

Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]

	Nine Months Ended				Three Months Ended
	February 29,		February 28,		February 29,		February 28,
	2020		2019		2020		2019
Numerator:
Net loss	$	(1,852,482)	$	(1,607,730)	$	(860,926)		($678,746)
Denominator for basic loss   per common share		9,882,459		9,103,225		9,814,504		9,322,549
Effect of dilutive securities:
Options and warrants		--		--		--		--
Denominator for diluted loss per common share		9,882,459		9,103,225		9,814,504		9,322,549
Basic net loss per common share	$	(0.19)	$	(0.18)	$	(0.09)	$	(0.07)
Diluted net loss per common share	$	(0.19)	$	(0.18)	$	(0.09)	$	(0.07)