Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021
Cash flows from operating activities:
Net income (loss)	$ (80,882)	$ 19,279
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	4,320	4,735
Stock-based compensation	35,183	28,079
Accretion of discounts on marketable securities	269	1,586
Amortization of right-of-use assets	2,039	1,434
Changes in operating assets and liabilities:
Receivable from collaboration partner	900	(1,584)
Prepaid expenses and other current assets	(3,095)	(382)
Other assets	(210)	(3,099)
Accounts payable	(383)	(347)
Accrued liabilities and accrued clinical supply costs	(7,287)	(5,488)
Deferred revenue	80,823	306,909
Lease liabilities	(3,156)	(2,992)
Other long-term liabilities	75	(314)
Net cash provided by operating activities	28,596	347,816
Cash flows from investing activities:
Purchase of property and equipment	(3,351)	(2,690)
Purchase of marketable securities	(394,345)	(139,716)
Maturities of marketable securities	220,301	228,800
Sale of marketable secuirities	0	10,696
Net cash provided by (used in) investing activities	(177,395)	97,090
Cash flows from financing activities:
Proceeds from the exercise of options to purchase common stock	3,013	20,688
Purchase of common stock under employee stock purchase plan	865	969
Net cash provided by financing activities	3,878	21,657
Net increase (decrease) in cash, cash equivalents, and restricted cash	(144,921)	466,563
Cash, cash equivalents, and restricted cash at beginning of period	330,624	51,441
Cash, cash equivalents, and restricted cash at end of period	185,703	518,004
Non-cash investing and financing activities:
Property and equipment purchases included in accounts payable and accrued liabilities	$ 633	$ 236