CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Cash flows from operating activities:
Net loss	$ (35,615,000)	$ (27,674,000)
Adjustments to reconcile net loss to net cash used in operating activities:
Accretion of discount on investments	9,000	37,000
Amortization of right of use assets	307,000	132,000
Depreciation expense	676,000	741,000
Stock-based compensation including ESPP	3,786,000	2,756,000
Changes in operating assets and liabilities:
Other assets	3,620,000	277,000
Right of use assets	(278,000)
Accounts payable	740,000	(502,000)
Accrued liabilities	(6,071,000)	(4,239,000)
Operating lease liabilities	(47,000)	(303,000)
Other liabilities	1,000	(111,000)
Deferred revenue from collaborations	12,438,000	(910,000)
Net cash and cash equivalents used in operating activities	(20,434,000)	(29,796,000)
Activities in available-for-sale investments:
Purchase of short-term investments	(59,889,000)
Maturities of investments		10,000,000
Purchases of property and equipment	(515,000)	(307,000)
Net cash and cash equivalents (used in) provided by investing activities	(60,404,000)	9,693,000
Cash flows from financing activities:
Payments on finance lease	(31,000)	(18,000)
Proceeds from the exercise of common stock option	10,000	96,000
Net cash and cash equivalents (used in) provided by financing activities	(21,000)	78,000
Net decrease in cash, cash equivalents, and restricted cash	(80,859,000)	(20,025,000)
Cash, cash equivalents, and restricted cash, beginning of period	186,980,000	220,943,000
Cash, cash equivalents, and restricted cash, end of period	106,121,000	200,918,000
Reconciliation to amounts on the consolidated balance sheet:
Cash and cash equivalents	104,562,000	200,362,000
Restricted cash	1,559,000	556,000
Cash, cash equivalents, and restricted cash, end of period	106,121,000	200,918,000
Supplemental disclosures of noncash financing and investing activities:
Mark to market adjustment for available-for-sale investments	(248,000)	(41,000)
Acquisition of right of use asset through operating lease obligation		184,000
Vesting of early exercised options	$ 84,000	42,000
Change in pension obligation		$ 2,000