Condensed Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Cash flows from operating activities:
Net loss	$ (43,971)	$ (36,892)
Adjustments to reconcile net loss to net cash used in operating activities:
Stock-based compensation expense	8,538	5,006
Depreciation and amortization	1,384	1,262
Non-cash lease expense	295	269
Non-cash interest expense	463	140
Accretion (amortization) of discount (premium) on investments, net	(1,550)	667
Provision for inventories	870	496
Other non-cash items	(18)	3
Changes in operating assets and liabilities:
Accounts receivable	(6,224)	(1,299)
Inventories	2,873	(4,184)
Prepaid expenses and other assets	569	137
Accounts payable	1,475	3,276
Accrued payroll and related benefits	(7,100)	(11,470)
Accrued expenses and other current liabilities	(2,337)	4,226
Accrued warranty liability	(51)	(76)
Deferred revenue	341	375
Operating lease liabilities	(313)	(271)
Net cash used in operating activities	(44,756)	(38,335)
Cash flows from investing activities:
Purchases of property and equipment	(810)	(1,478)
Purchases of investment securities	(68,147)	(64,712)
Sales and maturities of investment securities	71,600	32,800
Net cash provided by (used in) investing activities	2,643	(33,390)
Cash flows from financing activities:
Proceeds from stock option exercises and employee stock purchase plan purchases	5,277	3,723
Net cash provided by financing activities	5,277	3,723
Net decrease in cash, cash equivalents and restricted cash	(36,836)	(68,002)
Cash, cash equivalents and restricted cash as of beginning of period	76,533	215,659
Cash, cash equivalents and restricted cash as of end of period	39,697	147,657
Supplemental cash flow disclosures:
Cash paid for income taxes	201	205
Cash paid for interest	2,479	282
Cash paid for amounts included in the measurement of operating lease liabilities	313	271
Supplemental non-cash investing and financing activities:
Capital expenditures included in accounts payable and accrued expenses	$ 55	$ 907