CONDENSED STATEMENTS OF CASH FLOWS $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)
Operating activities
Net loss	$ (55,135)	$ (55,059)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	13,933	12,001
Depreciation and amortization	187	186
Amortization expense component of lease expense	1,055	969
Amortization of available-for-sale marketable securities, net	498	590
Realized gain on sale of available-for-sale marketable securities		(39)
Realized gain on sale of property and equipment		(70)
Changes in operating assets and liabilities:
Accounts receivable, net - related party	(9,623)
Inventory, net	749
Income tax receivable		810
Other receivables	4	(19,793)
Prepaid expenses	(16,043)	5,818
Accounts payable and accrued expenses	10,455	(3,069)
Operating lease liabilities	(1,300)	(1,186)
Net cash used in operating activities	(55,220)	(58,842)
Investing activities
Proceeds from maturities of available-for-sale marketable securities	162,185	134,220
Proceeds from redemptions of available-for-sale marketable securities, at par		13,500
Proceeds from sale of available-for-sale marketable securities	0	10,029
Purchases of available-for-sale marketable securities	(77,858)	(108,989)
Purchases of property and equipment	(43)
Proceeds from sale of property and equipment		70
Net cash provided by investing activities	84,284	48,830
Financing activities
Proceeds from the exercise of stock options	289	1,320
Net cash provided by financing activities	289	1,320
Net increase (decrease) in cash, cash equivalents and restricted cash	29,353	(8,692)
Cash, cash equivalents and restricted cash at beginning of period	13,861	32,091
Cash, cash equivalents and restricted cash at end of period	$ 43,214	23,399
Noncash investing and financing activities
Stock subscription receivable from Vifor International		$ 44,969