SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration risks (Details)	12 Months Ended
	Dec. 31, 2025 USD ($) customer	Dec. 31, 2024 USD ($) customer	Dec. 31, 2023 USD ($) customer
Concentration risks
Aggregate dollar amount of net sales	$ 38,266,211	$ 33,049,533	$ 43,596,926
Other products
Concentration risks
Aggregate dollar amount of net sales	$ 43,627	$ 45,852	$ 266,273
Net Sales | Customer Concentration Risk
Concentration risks
Number of significant customers | customer	3	3	4
Net Sales | Customer Concentration Risk | Significant customers
Concentration risks
Aggregate dollar amount of net sales	$ 20,600,000	$ 17,800,000	$ 25,900,000
Concentration risk, percentage	53.90%	53.80%	61.30%
Cost of Sales, Manufacturing | Supplier Concentration Risk | China
Concentration risks
Concentration risk, percentage	62.60%	83.90%	88.40%