CONDENSED STATEMENTS OF STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Common Stock Common Stock Subscribed in Private Offering	Common Stock	Additional Paid-In Capital	Stock Subscription Receivable	Accumulated Deficit	Accumulated Other Comprehensive Income (Loss)	Total
Balance, Value at Dec. 31, 2020		$ 50	$ 641,195		$ (392,317)	$ 73	$ 249,001
Balance, Shares at Dec. 31, 2020		49,872,213
Stock-based compensation expense			2,744				2,744
Shares issued upon exercise of stock options, value			688				688
Shares issued upon exercise of stock options, shares		45,035
Shares issued upon vesting of restricted stock units, value			1,388				1,388
Shares issued upon vesting of restricted stock units, shares		109,419
Net loss					(23,301)		(23,301)
Other comprehensive loss						(61)	(61)
Balance, Value at Mar. 31, 2021		$ 50	646,015		(415,618)	12	230,459
Balance, Shares at Mar. 31, 2021		50,026,667
Balance, Value at Dec. 31, 2020		$ 50	641,195		(392,317)	73	249,001
Balance, Shares at Dec. 31, 2020		49,872,213
Net loss							(55,059)
Other comprehensive loss						(72)
Balance, Value at Sep. 30, 2021	$ 3	$ 50	699,482	$ (44,969)	(447,376)	1	207,191
Balance, Shares at Sep. 30, 2021	3,282,391	50,175,988
Balance, Value at Mar. 31, 2021		$ 50	646,015		(415,618)	12	230,459
Balance, Shares at Mar. 31, 2021		50,026,667
Stock-based compensation expense			3,376				3,376
Shares issued upon exercise of stock options, value			293				293
Shares issued upon exercise of stock options, shares		25,494
Shares issued upon vesting of restricted stock units, value			100				100
Shares issued upon vesting of restricted stock units, shares		36,000
Net loss					(30,745)		(30,745)
Other comprehensive loss						(17)	(17)
Balance, Value at Jun. 30, 2021		$ 50	649,784		(446,363)	(5)	203,466
Balance, Shares at Jun. 30, 2021		50,088,161
Subscription of common stock in Vifor stock purchase, value	$ 3		44,966	(44,969)
Subscription of common stock in Vifor stock purchase, shares	3,282,391
Stock-based compensation expense			3,487				3,487
Shares issued upon exercise of stock options, value			339				339
Shares issued upon exercise of stock options, shares		43,825
Shares issued upon vesting of restricted stock units, value			906				906
Shares issued upon vesting of restricted stock units, shares		44,002
Net loss					(1,013)		(1,013)
Other comprehensive loss						6	6
Balance, Value at Sep. 30, 2021	$ 3	$ 50	699,482	$ (44,969)	(447,376)	1	207,191
Balance, Shares at Sep. 30, 2021	3,282,391	50,175,988
Balance, Value at Dec. 31, 2021		$ 53	708,585		(480,758)	(358)	227,522
Balance, Shares at Dec. 31, 2021		53,480,812
Stock-based compensation expense			4,266				4,266
Shares issued upon exercise of stock options, value			3				3
Shares issued upon exercise of stock options, shares		470
Shares issued upon vesting of restricted stock units, value			1,438				1,438
Shares issued upon vesting of restricted stock units, shares		109,943
Net loss					(27,749)		(27,749)
Other comprehensive loss						(1,365)	(1,365)
Balance, Value at Mar. 31, 2022		$ 53	714,292		(508,507)	(1,723)	204,115
Balance, Shares at Mar. 31, 2022		53,591,225
Balance, Value at Dec. 31, 2021		$ 53	708,585		(480,758)	(358)	227,522
Balance, Shares at Dec. 31, 2021		53,480,812
Net loss							(55,135)
Other comprehensive loss						(1,790)
Balance, Value at Sep. 30, 2022		$ 53	722,808		(535,893)	(2,148)	184,820
Balance, Shares at Sep. 30, 2022		53,733,607
Balance, Value at Mar. 31, 2022		$ 53	714,292		(508,507)	(1,723)	204,115
Balance, Shares at Mar. 31, 2022		53,591,225
Stock-based compensation expense			4,232				4,232
Shares issued upon exercise of stock options, value			182				182
Shares issued upon exercise of stock options, shares		30,000
Shares issued upon vesting of restricted stock units, value			423				423
Shares issued upon vesting of restricted stock units, shares		89,075
Net loss					(4,206)		(4,206)
Other comprehensive loss						(324)	(324)
Balance, Value at Jun. 30, 2022		$ 53	719,129		(512,713)	(2,047)	204,422
Balance, Shares at Jun. 30, 2022		53,710,300
Stock-based compensation expense			3,520				3,520
Shares issued upon exercise of stock options, value			104				104
Shares issued upon exercise of stock options, shares		15,807
Shares issued upon vesting of restricted stock units, value			55				55
Shares issued upon vesting of restricted stock units, shares		7,500
Net loss					(23,180)		(23,180)
Other comprehensive loss						(101)	(101)
Balance, Value at Sep. 30, 2022		$ 53	$ 722,808		$ (535,893)	$ (2,148)	$ 184,820
Balance, Shares at Sep. 30, 2022		53,733,607