Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Cash flows from operating activities:
Net loss	$ (48,235)	$ (115,178)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation of property and equipment	48	105
Amortization of debt issuance costs	100	0
Amortization of discount/premium on investments	74	402
Share-based compensation	7,301	5,696
Fair value of common stock issued related to asset acquisition	0	43,445
Note payable related to asset acquisition	0	14,000
Gain on sale of investments	(1)	(2)
Lease-related amortization	46	292
Changes in operating assets and liabilities:
Accounts receivable	0	304
Inventories	(1,365)	0
Prepaid expenses and other assets	917	(1,832)
Accounts payable, accrued liabilities and deferred revenue	7,108	2,149
Net cash used in operating activities	(34,007)	(50,619)
Cash flows from investing activities:
Purchases of property and equipment	0	(188)
Purchases of short-term investments	(5,258)	(100,860)
Purchases of long-term investments	0	(7,554)
Proceeds from sales of short-term investments	7,699	2,007
Proceeds from maturities of short-term investments	57,726	23,850
Net cash provided by (used in) investing activities	60,167	(82,745)
Cash flows from financing activities:
Proceeds from exercise of stock options	102	3,648
Proceeds from employee stock purchase plan	556	330
Proceeds from issuance of common stock, net of commissions	0	107,842
Payments of debt issuance costs	(129)	0
Payment of note payable related to asset acquisition	(14,000)	0
Net cash (used in) provided by financing activities	(13,471)	111,820
Net increase (decrease) in cash and cash equivalents	12,689	(21,544)
Cash and cash equivalents:
Beginning of period	15,397	46,989
End of period	$ 28,086	$ 25,445