Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2021	May 03, 2021
Document Information [Line Items]
Entity Registrant Name	ALPHA PRO TECH LTD
Entity Central Index Key	0000884269
Trading Symbol	apt
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity Small Business	true
Entity Interactive Data Current	Yes
Entity Common Stock, Shares Outstanding (in shares)		13,332,251
Entity Shell Company	false
Document Type	10-Q
Document Period End Date	Mar. 31, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	Q1
Amendment Flag	false
Title of 12(b) Security	Common Stock, $0.01 par value