Note 15 - Share-based Compensation (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)	4,385,477	3,977,289	2,516,924
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value	$ 1,307	$ 5,728	$ 6,917
Share Price (in dollars per share)	$ 2.98
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.54	$ 4.64	$ 3.95
Equity Incentive Plan [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Award Vesting Period (Year)	4 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Expiration Period (Year)	10 years
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Authorized (in shares)	9,098,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Number of Shares Available for Grant (in shares)	4,629,538
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Intrinsic Value	$ 1,300,000
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 4.54
Share-Based Compensation Arrangement by Share-Based Payment Award, Option, Nonvested, Weighted Average Exercise Price (in dollars per share)	$ 3.01	$ 5.12
Equity Incentive Plan [Member] \| Performance Based Stock Options [Member]
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Number (in shares)	993,835
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount	$ 3.3
Equity Incentive Plan [Member] \| Non Performance Based Options [Member]
Share-Based Payment Arrangement, Nonvested Award, Option, Cost Not yet Recognized, Amount	$ 2,300,000
Share-Based Payment Arrangement, Nonvested Award, Cost Not yet Recognized, Period for Recognition (Year)	1 year 4 months 24 days

Harvard Apparatus Regenerative Technology, Inc. 10-K