Condensed Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Current assets:
Cash and cash equivalents	$ 22,991	$ 31,683
Marketable securities	121,203	149,242
Income tax receivable	697	1,507
Other receivables	20,350	557
Prepaid expenses	6,258	12,076
Total current assets	171,499	195,065
Operating lease right-of-use assets	3,310	4,279
Marketable securities, non-current	49,221	70,565
Property and equipment, net	654	840
Restricted cash	408	408
Total assets	225,092	271,157
Current liabilities:
Accounts payable and accrued expenses	13,812	16,881
Operating lease liabilities, current	1,716	1,602
Total current liabilities	15,528	18,483
Operating lease liabilities, non-current	2,373	3,673
Commitments and contingencies (Note 15)
Stockholders' equity:
Preferred stock; $0.001 par value; 5,000,000 shares authorized at September 30, 2021 and December 31, 2020, zero shares issued and outstanding at September 30, 2021 and December 31, 2020
Common stock; $0.001 par value; 100,000,000 shares authorized at September 30, 2021 and December 31, 2020, 50,175,988 shares 49,872,213 shares issued and outstanding at September 30, 2021 and December 31, 2021, respectively	50	50
Common stock subscribed in Vifor stock purchase, or Private Offering; $0.001 par value; 3,282,391 shares at September 30, 2021	3
Additional paid-in capital	699,482	641,195
Stock subscription receivable	(44,969)
Accumulated deficit	(447,376)	(392,317)
Accumulated other comprehensive income	1	73
Total stockholders' equity	207,191	249,001
Total liabilities and stockholders' equity	$ 225,092	$ 271,157