REVENUE RECOGNITION - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) pharmacy	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Disaggregation of Revenue [Line Items]
Number of direct-to-patient pharmacies sold to | pharmacy	3
Revenue, performance obligation, description of timing	For FILSPARI, sales are recognized upon delivery of the product to the specialty pharmacies. The Company receives payments from its FILSPARI sales based on terms that are generally 30 days from shipment of the product to the specialty pharmacy. For the Company's other products, product sales are recognized upon delivery to the patient. The Company receives payments from sales of its other products, primarily through third party payers, based on terms that generally are within 30 days of delivery of product to the patient
Revenue increase in performance obligations satisfied in previous period | $	$ 0.4	$ 0.2	$ 0.2
United States | Revenue Benchmark | Geographic Concentration Risk
Disaggregation of Revenue [Line Items]
Concentration risk, percentage	99.00%