Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
Cash flows used in operating activities:
Net loss	$ (97,739)	$ (90,990)
Adjustments to reconcile net loss to cash used in operating activities:
Stock-based compensation expense	20,876	23,097
Depreciation and amortization expense	1,450	1,155
Reduction in carrying amount of right-of-use asset	4,596	4,394
Net (accretion) amortization of (discounts) premiums on marketable securities	(2,817)	1,118
Amortization of debt discount − related party	405	534
Loss on early extinguishment of debt	621	0
Other	120	0
Changes in operating assets and liabilities:
Accounts receivable	973	4,229
Prepaid expenses and other current and long-term assets	1,404	217
Accounts payable	104	(2,257)
Accrued expenses and other current liabilities	(3,866)	2,391
Operating lease liability	(3,489)	575
Deferred revenue	(5,467)	(21,274)
Net cash used in operating activities	(82,829)	(76,811)
Cash flows provided by investing activities:
Proceeds from maturities of marketable securities	219,975	216,382
Purchases of marketable securities	(92,020)	(163,238)
Purchases of property and equipment, net	(1,551)	(4,006)
Net cash provided by investing activities	126,404	49,138
Cash flows (used in) provided by financing activities:
Payment of long-term debt − related party	(12,500)	0
Payments for repurchase of common stock for tax withholding	(110)	0
Proceeds from exercise of stock options	58	730
Other	369	370
Net cash (used in) provided by financing activities	(12,183)	1,100
Net change in cash, cash equivalents and restricted cash	31,392	(26,573)
Cash, cash equivalents and restricted cash at beginning of period	33,033	79,403
Cash, cash equivalents and restricted cash at end of period	64,425	52,830
Reconciliation of cash, cash equivalents and restricted cash:
Cash, cash equivalents and restricted cash at end of period	64,425	52,830
Less: restricted cash	(3,454)	(3,279)
Cash and cash equivalents at end of the period	60,971	49,551
Supplemental disclosures of cash flow information:
Cash paid for income taxes	1,003	0
Cash paid for interest − related party	990	1,203
Cash paid for leases	6,421	5,083
Supplemental disclosures of non-cash investing and financing activities:
Capital expenditures in accounts payable and accrued expenses	54	1,455
Operating lease liabilities arising from obtaining right-of-use assets	$ 0	$ 44,067