Consolidated Statements of Stockholders' Equity (Deficit) - USD ($) $ in Thousands	Total	Promissory Note	PIPE Investors	Former Stockholders of Aerpio Upon Merger	Preferred Stock Series Seed Preferred Stock	Preferred Stock Series A Preferred Stock	Common Stock	Common Stock Promissory Note	Common Stock PIPE Investors	Common Stock Former Stockholders of Aerpio Upon Merger	Additional Paid-In Capital	Additional Paid-In Capital Promissory Note	Additional Paid-In Capital PIPE Investors	Additional Paid-In Capital Former Stockholders of Aerpio Upon Merger	Accumulated Other Comprehensive Loss	Accumulated Deficit
Balance (in shares) at Dec. 31, 2020	$ (12,432)					$ 1	$ 1				$ 20,161				$ 0	$ (32,595)
Balance at Dec. 31, 2020					734,000	7,212,000	2,542,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)							73,000
Issuance of common stock upon exercise of stock options	833										833
Issuance of common stock (in shares)									11,853,000	3,209,000
Issuance of common stock			$ 145,384	$ 105,888					$ 1				$ 145,383	$ 105,888
Conversion of convertible promissory note/preferred stock in to common stock upon merger (in shares)					(734,000)	(7,212,000)	2,520,000	698,000
Conversion of convertible promissory note/preferred stock in to common stock upon merger	(1)	$ 9,130				$ (1)						$ 9,130
Share-based compensation expense	2,106										2,106
Cumulative dividends paid on Series A preferred stock	(4,412)										(4,412)
Net loss	(110,090)															(110,090)
Balance (in shares) at Dec. 31, 2021	$ 136,406					$ 0	$ 2				279,089				0	(142,685)
Balance at Dec. 31, 2021					0	0	20,895,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of common stock upon exercise of stock options (in shares)	132,084						132,000
Issuance of common stock upon exercise of stock options	$ 401										401
Issuance of common stock upon exercise of warrants (in shares)							7,000
Issuance of common stock upon exercise of warrants	55										55
Issuance of common stock (in shares)									3,374,000
Issuance of common stock			$ 72,178										$ 72,178
Share-based compensation expense	9,643										9,643
Issuance of shares under the employee stock purchase plan (in shares)							27,000
Issuance of shares under the employee stock purchase plan	323										323
Other comprehensive loss	(115)														(115)
Net loss	(60,513)															(60,513)
Balance (in shares) at Dec. 31, 2022	$ 158,378					$ 0	$ 2				$ 361,689				$ (115)	$ (203,198)
Balance at Dec. 31, 2022					0	0	24,435,000