DEFERRED REVENUE, REFUND LIABILITY AND LIABILITY RELATED TO SALE OF FUTURE ROYALTIES - Summary of Deferred Revenue Balances (Details) - USD ($) $ in Thousands	Mar. 31, 2024	Dec. 31, 2023
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Short-term deferred revenue	$ 695	$ 0
Deferred revenue, net of current portion	43,296	$ 43,296
Contract with Customer, Liability, Total	43,991
Mitsubishi Tanabe Pharma Corporation
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Short-term deferred revenue	695
Deferred revenue, net of current portion	0
Contract with Customer, Liability, Total	695
Vifor (International) Ltd.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Short-term deferred revenue	0
Deferred revenue, net of current portion	43,296
Contract with Customer, Liability, Total	$ 43,296