Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES:
Net loss	$ (44,255)	$ (36,255)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	166	162
Stock-based compensation	8,860	7,742
Accretion/amortization of investments, net	(2,191)	161
Amortization of right-of-use assets – operating	427	411
Non-cash interest expense for the sale of future royalties	4,336	4,854
Changes in operating assets and liabilities:
Receivables from collaborative partners	(104)	(45)
Prepaid expenses and other assets	51	(1,221)
Accounts payable and other liabilities	8,533	3,536
Operating lease liabilities	(391)	(359)
Net cash used in operating activities	(24,568)	(21,014)
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchases of investments	(48,555)	(322,477)
Sales and maturities of investments	134,126	9,620
Purchases of property and equipment	(175)	(55)
Net cash provided by (used in) investing activities	85,396	(312,912)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from issuance of common stock	1,265	4,844
Repurchase and retirements of common stock	(37,526)	0
Repayment of liability for sale of future royalties	(1,270)	(233)
Payments for debt issuance costs	(43)	(2)
Net cash (used in) provided by financing activities	(37,574)	4,609
Net increase (decrease) in cash and cash equivalents	23,254	(329,317)
Cash, cash equivalents and restricted cash, beginning of period	71,308	495,729
Cash, cash equivalents and restricted cash, end of period	94,562	166,412
Non-cash investing and financing activities:
Amounts accrued for property and equipment	38	19
Amounts accrued for issuance costs related to the sale of future royalties	0	128
Amounts accrued for repurchases of common stock	1,290	0
Receivable related to issuance of common stock, upon exercise of stock options	$ (43)	$ 0