Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
Net loss	$ (130,849)	$ (104,467)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	28,105	44,438
Impairment of other investments	12,923	0
Depreciation and amortization expense	10,089	8,358
Net amortization and accretion on marketable securities	(3,925)	706
Non-cash lease income	(816)	(655)
Change in fair value of success payment liabilities	(603)	(264)
Loss on property and equipment disposals	430	84
Change in fair value of equity warrant	0	(14)
Changes in operating assets and liabilities:
Prepaid expenses, other current assets and other assets	641	9
Accounts payable	2,449	1,170
Accrued liabilities and other current liabilities	(3,592)	(7,159)
Deferred revenue	0	(36,300)
Operating lease liabilities, non-current	0	2,135
Other non-current liabilities	(225)	(226)
Net cash used in operating activities	(85,373)	(92,185)
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of property and equipment	(2,466)	(16,903)
Purchases of marketable securities	(141,815)	(185,855)
Sales and maturities of marketable securities	329,347	201,655
Net cash provided by (used in) investing activities	185,066	(1,103)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from exercise of stock options	83	4,125
Proceeds from employee stock purchase plan	1,163	887
Taxes paid related to net share settlement of equity awards	(119)	0
Net cash provided by financing activities	1,127	5,012
Net increase (decrease) in cash, cash equivalents and restricted cash	100,820	(88,276)
Cash, cash equivalents and restricted cash at beginning of period	123,834	294,294
Cash, cash equivalents and restricted cash at end of period	224,654	206,018
Represented by:
Cash and cash equivalents	224,372	205,739
Restricted cash	282	279
Total	224,654	206,018
SUPPLEMENTAL CASH FLOW INFORMATION
Cash paid for amounts included in the measurement of lease liabilities	5,215	5,399
Cash received for amounts related to tenant improvement allowances	0	2,042
Non-cash investing and financing activities:
Purchases of property and equipment included in accounts payable and accrued liabilities	$ 33	$ 3,553