Note 6 - Earnings Per Share - Amounts Used in Computing Earnings Per Share (Details) - USD ($)	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Income (Loss) attributable to LiqTech International Inc.	$ (3,873,419)	$ (2,563,811)	$ 303,499	$ 656,357	$ 146,786	$ 34,244	$ (6,133,731)	$ 837,387
Weighted average number of common shares used in basic earnings per share (in shares)	21,653,514			20,547,667			21,059,251	19,350,533
Effect of dilutive securities, stock options, RSUs, and warrants (in shares)							0	16,012
Weighted average number of common shares and potential dilutive common shares outstanding used in dilutive earnings per share (in shares)	21,653,514			20,563,540			21,059,251	19,366,545