CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Cash flows from operating activities:
Net loss	$ (27,674,000)	$ (20,029,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of discount on investments	37,000	5,000
Amortization of right of use assets	132,000	129,000
Depreciation expense	741,000	331,000
Stock-based compensation	2,756,000	606,000
Change in fair value of derivative liability		(20,000)
Change in fair value of redeemable convertible preferred stock liabilities		(166,000)
Changes in operating assets and liabilities:
Other assets	277,000	(528,000)
Right of use assets		(249,000)
Accounts payable	(502,000)	(304,000)
Accrued liabilities	(4,239,000)	183,000
Operating lease liabilities	(303,000)	(277,000)
Other liabilities	(111,000)
Deferred revenue from collaborations	(910,000)
Net cash and cash equivalents used in operating activities	(29,796,000)	(20,319,000)
Activities in available-for-sale investments:
Purchase of short-term investments		(32,096,000)
Purchase of long term investments		(13,183,000)
Activities in held-to-maturity investments:
Maturities of investments	10,000,000	22,600,000
Purchases of property and equipment	(307,000)	(1,090,000)
Net cash and cash equivalents provided by (used in) investing activities	9,693,000	(23,769,000)
Cash flows from financing activities:
Proceeds from exercise of warrants for series A convertible preferred stock		350,000
Payment of Series B-1 redeemable convertible preferred stock issuance cost		(405,000)
Payments on finance lease	(18,000)	(11,000)
Proceeds from the exercise of common stock option	96,000	18,000
Net cash and cash equivalents provided by (used in) financing activities	78,000	(48,000)
Net decrease in cash, cash equivalents, and restricted cash	(20,025,000)	(44,136,000)
Cash, cash equivalents, and restricted cash, beginning of period	220,943,000	70,103,000
Cash, cash equivalents, and restricted cash, end of period	200,918,000	25,967,000
Reconciliation to amounts on the consolidated balance sheet:
Cash and cash equivalents	200,362,000	25,415,000
Restricted cash	556,000	552,000
Cash, cash equivalents, and restricted cash, end of period	200,918,000	25,967,000
Supplemental disclosures of cash flow information:
Interest paid		2,000
Supplemental disclosures of noncash financing and investing activities:
Leasehold improvement directly paid by landlord		79,000
Mark to market adjustment for available-for-sale investments	41,000	401,000
Acquisition of right of use asset through operating lease obligation	184,000
Change in fair value of derivative liability upon exercise of warrants		137,000
Vesting of early exercised options	42,000	63,000
Property and equipment purchases in accounts payable		399,000
Change in pension obligation	$ (2,000)	$ 166,000