Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flow from operating activities
Net loss	$ (40,406)	$ (51,769)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	4,809	7,592
Depreciation	4,016	2,459
Amortization of premiums and discounts on marketable securities	2	213
Other non-cash items	(2,469)	(2,460)
Changes in operating assets and liabilities:
Related party collaboration receivable	581	6,254
Prepaid expenses and other current assets	6	893
Operating lease, right-of-use asset	2,556	1,922
Other non-current assets		69
Accounts payable	644	156
Accrued expenses	(3,652)	(3,357)
Operating lease liabilities	(2,647)	(1,891)
Other non-current liabilities	(287)
Deferred revenue	52,787	(4,092)
Net cash provided by (used in) operating activities	15,941	(44,011)
Cash flow from investing activities
Purchases of property and equipment	(1,280)	(602)
Purchases of marketable securities	(54,848)
Proceeds from sales and maturities of marketable securities		57,632
Net cash (used in) provided by investing activities	(56,128)	57,030
Cash flow from financing activities
Proceeds from the exercise of stock options	587	28
Proceeds from the purchase of common stock under ESPP	232	357
Net cash provided by financing activities	819	385
Net (decrease) increase in cash, cash equivalents, and restricted cash	(39,368)	13,404
Cash, cash equivalents, and restricted cash beginning of period	119,212	106,219
Cash, cash equivalents, and restricted cash end of period	79,844	119,623
Supplemental disclosure of cash and non-cash activities
Capital expenditures incurred but not yet paid	$ 113	$ 111