Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2023	Jun. 30, 2022
Cash flows from operating activities
Net loss	$ (82,717)	$ (10,380)
Adjustments to reconcile net loss to net cash (used in) provided by operating activities:
Depreciation and amortization	5,130	4,402
(Accretion of discount) amortization of premium on marketable debt securities	(4,345)	968
Stock-based compensation	26,162	23,408
Abandonment of capitalized intangible assets	594	1,047
Equity received in connection with license agreements	(10,000)	0
Change in fair value of equity securities	2,610	9,974
Impairment on equity securities	0	138
Loss on disposal of assets	1,379	125
Changes in operating assets and liabilities:
Accounts receivable and contract asset	8,978	12,100
Interest receivable from marketable debt securities	420	(448)
Prepaid expenses and other assets	1,127	4,183
Accounts payable	4,009	1,746
Accrued expenses	(288)	(3,095)
Lease liabilities and ROU assets	582	7,911
Deferred revenue	(22,455)	(1,995)
Net cash (used in) provided by operating activities	(68,814)	50,084
Cash flows from investing activities
Purchase of marketable securities	(276,715)	(206,148)
Purchase of intangible assets	(1,490)	(3,197)
Purchase of property and equipment	(14,636)	(14,443)
Proceeds from maturities and sale of marketable securities	339,580	76,390
Net cash provided by (used in) investing activities	46,739	(147,398)
Cash flows from financing activities
Proceeds from issuance of common stock upon exercise of stock awards	1,601	2,047
Proceeds from issuance of common stock under the Employee Stock Purchase Plan	1,242	1,197
Net cash provided by financing activities	2,843	3,244
Net decrease in cash and cash equivalents	(19,232)	(94,070)
Cash and cash equivalents, beginning of period	53,942	143,480
Cash and cash equivalents, end of period	34,710	49,410
Cash paid during the period for:
Interest	14	9
Supplemental disclosures of non-cash investing activities
Unrealized gain (loss) on marketable securities	$ 5,093	$ (7,435)

The sum of the periodic adjustments of the differences between securities' face values and purchase prices that are charged against earnings. This is called accretion if the security was purchased at a discount and amortization if it was purchased at premium. As a noncash item, this element is an adjustment to net income when calculating cash provided by or used in operations using the indirect method.

Name:	us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.