UNAUDITED CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Cash flows from operating activities
Net loss	$ (15,592)	$ (28,831)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation and amortization	572	524
Amortization and accretion of investments, net	(973)	(194)
Noncash lease expense	78	302
Inventory write-down	0	231
Gain on disposal of assets	(572)	(2)
Share-based compensation	1,320	2,040
Carrying value adjustment to assets held for sale	5,564	0
Changes in operating assets and liabilities:
Accounts receivable	(82)	299
Inventory	0	(1,026)
Prepaid expenses and other assets	(7,382)	(5,313)
Accounts payable	(2,573)	215
Accrued expenses and other liabilities	(3,066)	(1,144)
Operating lease liabilities	4	(340)
Net cash used in operating activities	(22,702)	(33,239)
Cash flows from investing activities
Purchase of property and equipment and other	(2,818)	(2,988)
Proceeds from sale of property and equipment	572	2
Purchase of investments	(23,707)	(31,394)
Proceeds from sale and maturity of investments	53,861	33,533
Net cash provided by (used in) investing activities	27,908	(847)
Cash flows from financing activities
Proceeds from exercise of common stock options	48	19
Taxes paid related to net share settlement of equity awards	(295)	(195)
Repurchase of treasury stock	(11,043)	0
Net cash used in financing activities	(11,290)	(176)
Net decrease in cash and cash equivalents and restricted cash	(6,084)	(34,262)
Cash and cash equivalents and restricted cash, beginning of period	21,464	120,133
Cash and cash equivalents and restricted cash, end of period	15,380	85,871
Supplemental disclosure of noncash investing and financing activities:
Repurchase of treasury stock included in accrued expenses	294	0
Acquisitions of property and equipment included in accounts payable and other	$ 468	$ 255