Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Cash flows used in operating activities:
Net loss	$ (70,702)	$ (59,032)
Adjustments to reconcile net loss to cash used in operating activities:
Stock-based compensation expense	12,676	17,086
Depreciation and amortization expense	1,003	740
Reduction in carrying amount of right-of-use asset	3,048	2,890
Net amortization (accretion) of premiums (discounts) on marketable securities	(1,724)	1,082
Amortization of debt discount − related party	354	354
Other	68	0
Changes in operating assets and liabilities:
Accounts receivable	445	4,007
Prepaid expenses and other current and long-term assets	2,096	1,722
Accounts payable	941	(564)
Accrued expenses and other current liabilities	(3,133)	(87)
Operating lease liability	(2,299)	(983)
Deferred revenue	5,105	(16,006)
Net cash used in operating activities	(52,122)	(48,791)
Cash flows provided by (used in) investing activities:
Proceeds from maturities of marketable securities	129,708	138,057
Purchases of marketable securities	(60,078)	(108,132)
Purchases of property and equipment, net	(951)	(701)
Net cash provided by investing activities	68,679	29,224
Cash flows (used in) provided by financing activities:
Payment of long-term debt − related party	(1,500)	0
Payments for repurchase of common stock for tax withholding	(94)	0
Proceeds from exercise of stock options	58	519
Other	106	220
Net cash (used in) provided by financing activities	(1,430)	739
Net change in cash, cash equivalents and restricted cash	15,127	(18,828)
Cash, cash equivalents and restricted cash at beginning of period	33,033	79,403
Cash, cash equivalents and restricted cash at end of period	48,160	60,575
Reconciliation of cash, cash equivalents and restricted cash:
Cash, cash equivalents and restricted cash at end of period	48,160	60,575
Less: restricted cash	(3,279)	(3,279)
Cash and cash equivalents at end of the period	44,881	57,296
Supplemental disclosures of cash flow information:
Cash paid for interest − related party	852	828
Cash paid for leases	4,271	2,996
Supplemental disclosures of non-cash investing and financing activities:
Capital expenditures in accounts payable and accrued expenses	223	3,270
Operating lease liabilities arising from obtaining right-of-use assets	$ 0	$ 44,067