LICENSE, COLLABORATION AND OTHER REVENUE - CSL Vifor License Agreement (Details) $ / shares in Units, $ in Thousands		1 Months Ended	3 Months Ended		9 Months Ended
	Feb. 18, 2022 USD ($) $ / shares	May 31, 2017 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) shares	Sep. 30, 2022 USD ($)	Sep. 30, 2023 USD ($) performanceObligation shares	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($) shares	Mar. 18, 2022 USD ($)
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, issued (in shares) | shares			188,313,807		188,313,807		184,135,714
Deferred revenue, net of current portion			$ 43,296		$ 43,296		$ 43,296
Refund liability to customer, amortization of discount			700	$ 1,100	2,400	$ 2,300
Refund liability to customer, amortization of deferred gain			1,000	$ 900	3,000	$ 1,800
Refund liability to customer			40,346		40,346		$ 40,992
Vifor (International) Ltd.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract termination, prior written notice period	30 months
Private Placement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Sale of stock, price per share (in dollars per share) | $ / shares	$ 5.00
Vifor (International) Ltd.
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Contract termination, prior written notice period	6 months
Refund liability to customer, gross								$ 40,000
Refund liability to customer			40,300		40,300
Vifor (International) Ltd. | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Revenue, remaining performance obligation, profit share percentage	66.00%
Upfront payment	$ 25,000
Deferred revenue, net of current portion		$ 4,700	18,300		$ 18,300
Number of performance obligations | performanceObligation					1
Transaction price			43,300		$ 43,300
Refund liability, percentage								50.00%
Refund liability to customer, interest rate								15.00%
Vifor (International) Ltd. | License Agreement
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Common stock, issued (in shares) | shares		3,571,429
Sale of stock, price per share (in dollars per share) | $ / shares		$ 14.00
Proceeds from common stock sold		$ 50,000
Vifor International Limited, First Investment | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, net of current portion			4,700		4,700
Vifor International Limited, Second Investment | License
Collaborative Arrangement and Arrangement Other than Collaborative [Line Items]
Deferred revenue, net of current portion			$ 13,600		$ 13,600