Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (34,734)	$ (107,318)
Adjustments to reconcile net income (loss) to net cash used in operating activities:
Depreciation and amortization	2,973	3,130
Stock-based compensation	24,417	17,878
Amortization of premiums and accretion of discounts on marketable securities	718	1,152
Amortization of right-of-use assets	1,343	938
Changes in operating assets and liabilities:
Receivable from collaboration partner	(1,425)	0
Prepaid expenses and other current assets	(2,279)	(1,557)
Other assets	(345)	(3,376)
Accounts payable	(530)	9,148
Accrued liabilities and accrued clinical supply costs	(6,175)	(4,225)
Deferred revenue	95,675	(10,678)
Lease liabilities	(2,064)	(2,014)
Other long-term liabilities	75	(314)
Net cash provided by (used in) operating activities	77,649	(97,236)
Cash flows from investing activities:
Purchase of property and equipment	(1,436)	(1,775)
Purchase of marketable securities	(321,290)	(5,081)
Maturities of marketable securities	84,801	173,000
Net cash provided by (used in) investing activities	(237,925)	166,144
Cash flows from financing activities:
Proceeds from the exercise of options to purchase common stock	2,524	5,867
Purchase of common stock under employee stock option plan	865	969
Net cash provided by financing activities	3,389	6,836
Net increase (decrease) in cash, cash equivalents, and restricted cash	(156,887)	75,744
Cash, cash equivalents, and restricted cash at beginning of period	330,624	51,441
Cash, cash equivalents, and restricted cash at end of period	173,737	127,185
Non-cash investing and financing activities:
Property and equipment purchases included in accounts payable and accrued liabilities	$ 945	$ 348